akkartik/spell-cards.love - Change LXTTOB33N2HCUZFIUDRQGGBVHK2HODRG4NBLH6RXRQZDCHF27BSAC

extract a couple of files

Created by Kartik K. Agaram on June 3, 2022

LXTTOB33N2HCUZFIUDRQGGBVHK2HODRG4NBLH6RXRQZDCHF27BSAC

Dependencies

In channels

main

Change contents

File addition: text_tests.lua (----------)

[8.2]

-- major tests for text editing flows
-- This still isn't quite as thorough as I'd like.
function test_draw_text()
  io.write('\ntest_draw_text')
  App.screen.init{width=120, height=60}
  Lines = load_array{'abc', 'def', 'ghi'}
  Line_width = App.screen.width
  Cursor1 = {line=1, pos=1}
  Screen_top1 = {line=1, pos=1}
  Screen_bottom1 = {}
  App.draw()
  local y = Margin_top
  App.screen.check(y, 'abc', 'F - test_draw_text/screen:1')
  y = y + Line_height
  App.screen.check(y, 'def', 'F - test_draw_text/screen:2')
  y = y + Line_height
  App.screen.check(y, 'ghi', 'F - test_draw_text/screen:3')
end
function test_draw_wrapping_text()
  io.write('\ntest_draw_wrapping_text')
  App.screen.init{width=50, height=60}
  Lines = load_array{'abc', 'defgh', 'xyz'}
  Line_width = App.screen.width
  Cursor1 = {line=1, pos=1}
  Screen_top1 = {line=1, pos=1}
  Screen_bottom1 = {}
  App.draw()
  local y = Margin_top
  App.screen.check(y, 'abc', 'F - test_draw_wrapping_text/screen:1')
  y = y + Line_height
  App.screen.check(y, 'def', 'F - test_draw_wrapping_text/screen:2')
  y = y + Line_height
  App.screen.check(y, 'gh', 'F - test_draw_wrapping_text/screen:3')
end
function test_draw_word_wrapping_text()
  io.write('\ntest_draw_word_wrapping_text')
  App.screen.init{width=60, height=60}
  Lines = load_array{'abc def ghi', 'jkl'}
  Line_width = App.screen.width
  Cursor1 = {line=1, pos=1}
  Screen_top1 = {line=1, pos=1}
  Screen_bottom1 = {}
  App.draw()
  local y = Margin_top
  App.screen.check(y, 'abc ', 'F - test_draw_word_wrapping_text/screen:1')
  y = y + Line_height
  App.screen.check(y, 'def ', 'F - test_draw_word_wrapping_text/screen:2')
  y = y + Line_height
  App.screen.check(y, 'ghi', 'F - test_draw_word_wrapping_text/screen:3')
end
function test_draw_text_wrapping_within_word()
  -- arrange a screen line that needs to be split within a word
  io.write('\ntest_draw_text_wrapping_within_word')
  App.screen.init{width=60, height=60}
  Lines = load_array{'abcd e fghijk', 'xyz'}
  Line_width = App.screen.width
  Cursor1 = {line=1, pos=1}
  Screen_top1 = {line=1, pos=1}
  Screen_bottom1 = {}
  App.draw()
  local y = Margin_top
  App.screen.check(y, 'abcd ', 'F - test_draw_text_wrapping_within_word/screen:1')
  y = y + Line_height
  App.screen.check(y, 'e fghi', 'F - test_draw_text_wrapping_within_word/screen:2')
  y = y + Line_height
  App.screen.check(y, 'jk', 'F - test_draw_text_wrapping_within_word/screen:3')
end
function test_edit_wrapping_text()
  io.write('\ntest_edit_wrapping_text')
  App.screen.init{width=50, height=60}
  Lines = load_array{'abc', 'def', 'xyz'}
  Line_width = App.screen.width
  Cursor1 = {line=2, pos=4}
  Screen_top1 = {line=1, pos=1}
  Screen_bottom1 = {}
  App.run_after_textinput('g')
  App.run_after_textinput('h')
  App.run_after_textinput('i')
  App.run_after_textinput('j')
  App.run_after_textinput('k')
  App.run_after_textinput('l')
  local y = Margin_top
  App.screen.check(y, 'abc', 'F - test_edit_wrapping_text/screen:1')
  y = y + Line_height
  App.screen.check(y, 'def', 'F - test_edit_wrapping_text/screen:2')
  y = y + Line_height
  App.screen.check(y, 'ghij', 'F - test_edit_wrapping_text/screen:3')
end
function test_insert_newline()
  io.write('\ntest_insert_newline')
  -- display a few lines with cursor on bottom line
  App.screen.init{width=25+30, height=60}
  Lines = load_array{'abc', 'def', 'ghi', 'jkl'}
  Line_width = App.screen.width
  Cursor1 = {line=1, pos=2}
  Screen_top1 = {line=1, pos=1}
  Screen_bottom1 = {}
  App.draw()
  local y = Margin_top
  App.screen.check(y, 'abc', 'F - test_insert_newline/baseline/screen:1')
  y = y + Line_height
  App.screen.check(y, 'def', 'F - test_insert_newline/baseline/screen:2')
  y = y + Line_height
  App.screen.check(y, 'ghi', 'F - test_insert_newline/baseline/screen:3')
  -- after hitting the enter key the screen scrolls down
  App.run_after_keychord('return')
  check_eq(Screen_top1.line, 1, 'F - test_insert_newline/screen_top')
  check_eq(Cursor1.line, 2, 'F - test_insert_newline/cursor:line')
  check_eq(Cursor1.pos, 1, 'F - test_insert_newline/cursor:pos')
  y = Margin_top
  App.screen.check(y, 'a', 'F - test_insert_newline/screen:1')
  y = y + Line_height
  App.screen.check(y, 'bc', 'F - test_insert_newline/screen:2')
  y = y + Line_height
  App.screen.check(y, 'def', 'F - test_insert_newline/screen:3')
end
function test_insert_from_clipboard()
  io.write('\ntest_insert_from_clipboard')
  -- display a few lines with cursor on bottom line
  App.screen.init{width=25+30, height=60}
  Lines = load_array{'abc', 'def', 'ghi', 'jkl'}
  Line_width = App.screen.width
  Cursor1 = {line=1, pos=2}
  Screen_top1 = {line=1, pos=1}
  Screen_bottom1 = {}
  App.draw()
  local y = Margin_top
  App.screen.check(y, 'abc', 'F - test_insert_from_clipboard/baseline/screen:1')
  y = y + Line_height
  App.screen.check(y, 'def', 'F - test_insert_from_clipboard/baseline/screen:2')
  y = y + Line_height
  App.screen.check(y, 'ghi', 'F - test_insert_from_clipboard/baseline/screen:3')
  -- after hitting the enter key the screen scrolls down
  App.clipboard = 'xy\nz'
  App.run_after_keychord('C-v')
  check_eq(Screen_top1.line, 1, 'F - test_insert_from_clipboard/screen_top')
  check_eq(Cursor1.line, 2, 'F - test_insert_from_clipboard/cursor:line')
  check_eq(Cursor1.pos, 2, 'F - test_insert_from_clipboard/cursor:pos')
  y = Margin_top
  App.screen.check(y, 'axy', 'F - test_insert_from_clipboard/screen:1')
  y = y + Line_height
  App.screen.check(y, 'zbc', 'F - test_insert_from_clipboard/screen:2')
  y = y + Line_height
  App.screen.check(y, 'def', 'F - test_insert_from_clipboard/screen:3')
end
function test_move_cursor_using_mouse()
  io.write('\ntest_move_cursor_using_mouse')
  App.screen.init{width=50, height=60}
  Lines = load_array{'abc', 'def', 'xyz'}
  Line_width = App.screen.width
  Cursor1 = {line=1, pos=1}
  Screen_top1 = {line=1, pos=1}
  Screen_bottom1 = {}
  App.draw()  -- populate line.y for each line in Lines
  local screen_left_margin = 25  -- pixels
  App.run_after_mouserelease(screen_left_margin+8,Margin_top+5, '1')
  check_eq(Cursor1.line, 1, 'F - test_move_cursor_using_mouse/cursor:line')
  check_eq(Cursor1.pos, 2, 'F - test_move_cursor_using_mouse/cursor:pos')
end
function test_pagedown()
  io.write('\ntest_pagedown')
  App.screen.init{width=120, height=45}
  Lines = load_array{'abc', 'def', 'ghi'}
  Line_width = App.screen.width
  Cursor1 = {line=1, pos=1}
  Screen_top1 = {line=1, pos=1}
  Screen_bottom1 = {}
  -- initially the first two lines are displayed
  App.draw()
  local y = Margin_top
  App.screen.check(y, 'abc', 'F - test_pagedown/baseline/screen:1')
  y = y + Line_height
  App.screen.check(y, 'def', 'F - test_pagedown/baseline/screen:2')
  -- after pagedown the bottom line becomes the top
  App.run_after_keychord('pagedown')
  check_eq(Screen_top1.line, 2, 'F - test_pagedown/screen_top')
  check_eq(Cursor1.line, 2, 'F - test_pagedown/cursor')
  y = Margin_top
  App.screen.check(y, 'def', 'F - test_pagedown/screen:1')
  y = y + Line_height
  App.screen.check(y, 'ghi', 'F - test_pagedown/screen:2')
end
function test_pagedown_skips_drawings()
  io.write('\ntest_pagedown_skips_drawings')
  -- some lines of text with a drawing intermixed
  App.screen.init{width=50, height=80}
  Lines = load_array{'abc',               -- height 15
                     '```lines', '```',   -- height 25
                     'def',               -- height 15
                     'ghi'}               -- height 15
  check_eq(Lines[2].mode, 'drawing', 'F - test_pagedown_skips_drawings/baseline/lines')
  Line_width = App.screen.width
  Cursor1 = {line=1, pos=1}
  Screen_top1 = {line=1, pos=1}
  Screen_bottom1 = {}
  local drawing_height = 20 + App.screen.width / 2  -- default
  -- initially the screen displays the first line and the drawing
  -- 15px margin + 15px line1 + 10px margin + 25px drawing + 10px margin = 75px < screen height 80px
  App.draw()
  local y = Margin_top
  App.screen.check(y, 'abc', 'F - test_pagedown_skips_drawings/baseline/screen:1')
  -- after pagedown the screen draws the drawing up top
  -- 15px margin + 10px margin + 25px drawing + 10px margin + 15px line3 = 75px < screen height 80px
  App.run_after_keychord('pagedown')
  check_eq(Screen_top1.line, 2, 'F - test_pagedown_skips_drawings/screen_top')
  check_eq(Cursor1.line, 3, 'F - test_pagedown_skips_drawings/cursor')
  y = Margin_top + drawing_height
  App.screen.check(y, 'def', 'F - test_pagedown_skips_drawings/screen:1')
end
function test_pagedown_shows_one_screen_line_in_common()
  io.write('\ntest_pagedown_shows_one_screen_line_in_common')
  -- some lines of text with a drawing intermixed
  App.screen.init{width=50, height=60}
  Lines = load_array{'abc', 'def ghi jkl', 'mno'}
  Line_width = App.screen.width
  Cursor1 = {line=1, pos=1}
  Screen_top1 = {line=1, pos=1}
  Screen_bottom1 = {}
  App.draw()
  local y = Margin_top
  App.screen.check(y, 'abc', 'F - test_pagedown_shows_one_screen_line_in_common/baseline/screen:1')
  y = y + Line_height
  App.screen.check(y, 'def ', 'F - test_pagedown_shows_one_screen_line_in_common/baseline/screen:2')
  y = y + Line_height
  App.screen.check(y, 'ghi ', 'F - test_pagedown_shows_one_screen_line_in_common/baseline/screen:3')
  -- after pagedown the bottom screen line becomes the top
  App.run_after_keychord('pagedown')
  check_eq(Screen_top1.line, 2, 'F - test_pagedown_shows_one_screen_line_in_common/screen_top:line')
  check_eq(Screen_top1.pos, 5, 'F - test_pagedown_shows_one_screen_line_in_common/screen_top:pos')
  check_eq(Cursor1.line, 2, 'F - test_pagedown_shows_one_screen_line_in_common/cursor:line')
  check_eq(Cursor1.pos, 5, 'F - test_pagedown_shows_one_screen_line_in_common/cursor:pos')
  y = Margin_top
  App.screen.check(y, 'ghi ', 'F - test_pagedown_shows_one_screen_line_in_common/screen:1')
  y = y + Line_height
  App.screen.check(y, 'jkl', 'F - test_pagedown_shows_one_screen_line_in_common/screen:2')
  y = y + Line_height
  App.screen.check(y, 'mn', 'F - test_pagedown_shows_one_screen_line_in_common/screen:3')
end
function test_down_arrow_moves_cursor()
  io.write('\ntest_down_arrow_moves_cursor')
  App.screen.init{width=120, height=60}
  Lines = load_array{'abc', 'def', 'ghi', 'jkl'}
  Line_width = App.screen.width
  Cursor1 = {line=1, pos=1}
  Screen_top1 = {line=1, pos=1}
  Screen_bottom1 = {}
  -- initially the first three lines are displayed
  App.draw()
  local y = Margin_top
  App.screen.check(y, 'abc', 'F - test_down_arrow_moves_cursor/baseline/screen:1')
  y = y + Line_height
  App.screen.check(y, 'def', 'F - test_down_arrow_moves_cursor/baseline/screen:2')
  y = y + Line_height
  App.screen.check(y, 'ghi', 'F - test_down_arrow_moves_cursor/baseline/screen:3')
  -- after hitting the down arrow, the cursor moves down by 1 line
  App.run_after_keychord('down')
  check_eq(Screen_top1.line, 1, 'F - test_down_arrow_moves_cursor/screen_top')
  check_eq(Cursor1.line, 2, 'F - test_down_arrow_moves_cursor/cursor')
  -- the screen is unchanged
  y = Margin_top
  App.screen.check(y, 'abc', 'F - test_down_arrow_moves_cursor/screen:1')
  y = y + Line_height
  App.screen.check(y, 'def', 'F - test_down_arrow_moves_cursor/screen:2')
  y = y + Line_height
  App.screen.check(y, 'ghi', 'F - test_down_arrow_moves_cursor/screen:3')
end
function test_down_arrow_scrolls_down_by_one_line()
  io.write('\ntest_down_arrow_scrolls_down_by_one_line')
  -- display the first three lines with the cursor on the bottom line
  App.screen.init{width=120, height=60}
  Lines = load_array{'abc', 'def', 'ghi', 'jkl'}
  Line_width = App.screen.width
  Cursor1 = {line=3, pos=1}
  Screen_top1 = {line=1, pos=1}
  Screen_bottom1 = {}
  App.draw()
  local y = Margin_top
  App.screen.check(y, 'abc', 'F - test_down_arrow_scrolls_down_by_one_line/baseline/screen:1')
  y = y + Line_height
  App.screen.check(y, 'def', 'F - test_down_arrow_scrolls_down_by_one_line/baseline/screen:2')
  y = y + Line_height
  App.screen.check(y, 'ghi', 'F - test_down_arrow_scrolls_down_by_one_line/baseline/screen:3')
  -- after hitting the down arrow the screen scrolls down by one line
  App.run_after_keychord('down')
  check_eq(Screen_top1.line, 2, 'F - test_down_arrow_scrolls_down_by_one_line/screen_top')
  check_eq(Cursor1.line, 4, 'F - test_down_arrow_scrolls_down_by_one_line/cursor')
  y = Margin_top
  App.screen.check(y, 'def', 'F - test_down_arrow_scrolls_down_by_one_line/screen:1')
  y = y + Line_height
  App.screen.check(y, 'ghi', 'F - test_down_arrow_scrolls_down_by_one_line/screen:2')
  y = y + Line_height
  App.screen.check(y, 'jkl', 'F - test_down_arrow_scrolls_down_by_one_line/screen:3')
end
function test_down_arrow_scrolls_down_by_one_screen_line()
  io.write('\ntest_down_arrow_scrolls_down_by_one_screen_line')
  -- display the first three lines with the cursor on the bottom line
  App.screen.init{width=25+30, height=60}
  Lines = load_array{'abc', 'def', 'ghi jkl', 'mno'}
  Line_width = App.screen.width
  Cursor1 = {line=3, pos=1}
  Screen_top1 = {line=1, pos=1}
  Screen_bottom1 = {}
  App.draw()
  local y = Margin_top
  App.screen.check(y, 'abc', 'F - test_down_arrow_scrolls_down_by_one_screen_line/baseline/screen:1')
  y = y + Line_height
  App.screen.check(y, 'def', 'F - test_down_arrow_scrolls_down_by_one_screen_line/baseline/screen:2')
  y = y + Line_height
  App.screen.check(y, 'ghi ', 'F - test_down_arrow_scrolls_down_by_one_screen_line/baseline/screen:3')  -- line wrapping includes trailing whitespace
  -- after hitting the down arrow the screen scrolls down by one line
  App.run_after_keychord('down')
  check_eq(Screen_top1.line, 2, 'F - test_down_arrow_scrolls_down_by_one_screen_line/screen_top')
  check_eq(Cursor1.line, 3, 'F - test_down_arrow_scrolls_down_by_one_screen_line/cursor:line')
  check_eq(Cursor1.pos, 5, 'F - test_down_arrow_scrolls_down_by_one_screen_line/cursor:pos')
  y = Margin_top
  App.screen.check(y, 'def', 'F - test_down_arrow_scrolls_down_by_one_screen_line/screen:1')
  y = y + Line_height
  App.screen.check(y, 'ghi ', 'F - test_down_arrow_scrolls_down_by_one_screen_line/screen:2')
  y = y + Line_height
  App.screen.check(y, 'jkl', 'F - test_down_arrow_scrolls_down_by_one_screen_line/screen:3')
end
function test_down_arrow_scrolls_down_by_one_screen_line_after_splitting_within_word()
  io.write('\ntest_down_arrow_scrolls_down_by_one_screen_line_after_splitting_within_word')
  -- display the first three lines with the cursor on the bottom line
  App.screen.init{width=25+30, height=60}
  Lines = load_array{'abc', 'def', 'ghijkl', 'mno'}
  Line_width = App.screen.width
  Cursor1 = {line=3, pos=1}
  Screen_top1 = {line=1, pos=1}
  Screen_bottom1 = {}
  App.draw()
  local y = Margin_top
  App.screen.check(y, 'abc', 'F - test_down_arrow_scrolls_down_by_one_screen_line_after_splitting_within_word/baseline/screen:1')
  y = y + Line_height
  App.screen.check(y, 'def', 'F - test_down_arrow_scrolls_down_by_one_screen_line_after_splitting_within_word/baseline/screen:2')
  y = y + Line_height
  App.screen.check(y, 'ghijk', 'F - test_down_arrow_scrolls_down_by_one_screen_line_after_splitting_within_word/baseline/screen:3')
  -- after hitting the down arrow the screen scrolls down by one line
  App.run_after_keychord('down')
  check_eq(Screen_top1.line, 2, 'F - test_down_arrow_scrolls_down_by_one_screen_line_after_splitting_within_word/screen_top')
  check_eq(Cursor1.line, 3, 'F - test_down_arrow_scrolls_down_by_one_screen_line_after_splitting_within_word/cursor:line')
  check_eq(Cursor1.pos, 6, 'F - test_down_arrow_scrolls_down_by_one_screen_line_after_splitting_within_word/cursor:pos')
  y = Margin_top
  App.screen.check(y, 'def', 'F - test_down_arrow_scrolls_down_by_one_screen_line_after_splitting_within_word/screen:1')
  y = y + Line_height
  App.screen.check(y, 'ghijk', 'F - test_down_arrow_scrolls_down_by_one_screen_line_after_splitting_within_word/screen:2')
  y = y + Line_height
  App.screen.check(y, 'l', 'F - test_down_arrow_scrolls_down_by_one_screen_line_after_splitting_within_word/screen:3')
end
function test_page_down_followed_by_down_arrow_does_not_scroll_screen_up()
  io.write('\ntest_page_down_followed_by_down_arrow_does_not_scroll_screen_up')
  App.screen.init{width=25+30, height=60}
  Lines = load_array{'abc', 'def', 'ghijkl', 'mno'}
  Line_width = App.screen.width
  Cursor1 = {line=3, pos=1}
  Screen_top1 = {line=1, pos=1}
  Screen_bottom1 = {}
  App.draw()
  local y = Margin_top
  App.screen.check(y, 'abc', 'F - test_page_down_followed_by_down_arrow_does_not_scroll_screen_up/baseline/screen:1')
  y = y + Line_height
  App.screen.check(y, 'def', 'F - test_page_down_followed_by_down_arrow_does_not_scroll_screen_up/baseline/screen:2')
  y = y + Line_height
  App.screen.check(y, 'ghijk', 'F - test_page_down_followed_by_down_arrow_does_not_scroll_screen_up/baseline/screen:3')
  -- after hitting pagedown the screen scrolls down to start of a long line
  App.run_after_keychord('pagedown')
  check_eq(Screen_top1.line, 3, 'F - test_page_down_followed_by_down_arrow_does_not_scroll_screen_up/baseline2/screen_top')
  check_eq(Cursor1.line, 3, 'F - test_page_down_followed_by_down_arrow_does_not_scroll_screen_up/baseline2/cursor:line')
  check_eq(Cursor1.pos, 1, 'F - test_page_down_followed_by_down_arrow_does_not_scroll_screen_up/baseline2/cursor:pos')
  -- after hitting down arrow the screen doesn't scroll down further, and certainly doesn't scroll up
  App.run_after_keychord('down')
  check_eq(Screen_top1.line, 3, 'F - test_page_down_followed_by_down_arrow_does_not_scroll_screen_up/screen_top')
  check_eq(Cursor1.line, 3, 'F - test_page_down_followed_by_down_arrow_does_not_scroll_screen_up/cursor:line')
  check_eq(Cursor1.pos, 6, 'F - test_page_down_followed_by_down_arrow_does_not_scroll_screen_up/cursor:pos')
  y = Margin_top
  App.screen.check(y, 'ghijk', 'F - test_page_down_followed_by_down_arrow_does_not_scroll_screen_up/screen:1')
  y = y + Line_height
  App.screen.check(y, 'l', 'F - test_page_down_followed_by_down_arrow_does_not_scroll_screen_up/screen:2')
  y = y + Line_height
  App.screen.check(y, 'mno', 'F - test_page_down_followed_by_down_arrow_does_not_scroll_screen_up/screen:3')
end
function test_up_arrow_moves_cursor()
  io.write('\ntest_up_arrow_moves_cursor')
  -- display the first 3 lines with the cursor on the bottom line
  App.screen.init{width=120, height=60}
  Lines = load_array{'abc', 'def', 'ghi', 'jkl'}
  Line_width = 120
  Cursor1 = {line=3, pos=1}
  Screen_top1 = {line=1, pos=1}
  Screen_bottom1 = {}
  App.draw()
  local y = Margin_top
  App.screen.check(y, 'abc', 'F - test_up_arrow_moves_cursor/baseline/screen:1')
  y = y + Line_height
  App.screen.check(y, 'def', 'F - test_up_arrow_moves_cursor/baseline/screen:2')
  y = y + Line_height
  App.screen.check(y, 'ghi', 'F - test_up_arrow_moves_cursor/baseline/screen:3')
  -- after hitting the up arrow the cursor moves up by 1 line
  App.run_after_keychord('up')
  check_eq(Screen_top1.line, 1, 'F - test_up_arrow_moves_cursor/screen_top')
  check_eq(Cursor1.line, 2, 'F - test_up_arrow_moves_cursor/cursor')
  -- the screen is unchanged
  y = Margin_top
  App.screen.check(y, 'abc', 'F - test_up_arrow_moves_cursor/screen:1')
  y = y + Line_height
  App.screen.check(y, 'def', 'F - test_up_arrow_moves_cursor/screen:2')
  y = y + Line_height
  App.screen.check(y, 'ghi', 'F - test_up_arrow_moves_cursor/screen:3')
end
function test_up_arrow_scrolls_up_by_one_line()
  io.write('\ntest_up_arrow_scrolls_up_by_one_line')
  -- display the lines 2/3/4 with the cursor on line 2
  App.screen.init{width=120, height=60}
  Lines = load_array{'abc', 'def', 'ghi', 'jkl'}
  Line_width = 120
  Cursor1 = {line=2, pos=1}
  Screen_top1 = {line=2, pos=1}
  Screen_bottom1 = {}
  App.draw()
  local y = Margin_top
  App.screen.check(y, 'def', 'F - test_up_arrow_scrolls_up_by_one_line/baseline/screen:1')
  y = y + Line_height
  App.screen.check(y, 'ghi', 'F - test_up_arrow_scrolls_up_by_one_line/baseline/screen:2')
  y = y + Line_height
  App.screen.check(y, 'jkl', 'F - test_up_arrow_scrolls_up_by_one_line/baseline/screen:3')
  -- after hitting the up arrow the screen scrolls up by one line
  App.run_after_keychord('up')
  check_eq(Screen_top1.line, 1, 'F - test_up_arrow_scrolls_up_by_one_line/screen_top')
  check_eq(Cursor1.line, 1, 'F - test_up_arrow_scrolls_up_by_one_line/cursor')
  y = Margin_top
  App.screen.check(y, 'abc', 'F - test_up_arrow_scrolls_up_by_one_line/screen:1')
  y = y + Line_height
  App.screen.check(y, 'def', 'F - test_up_arrow_scrolls_up_by_one_line/screen:2')
  y = y + Line_height
  App.screen.check(y, 'ghi', 'F - test_up_arrow_scrolls_up_by_one_line/screen:3')
end
function test_up_arrow_scrolls_up_by_one_screen_line()
  io.write('\ntest_up_arrow_scrolls_up_by_one_screen_line')
  -- display lines starting from second screen line of a line
  App.screen.init{width=25+30, height=60}
  Lines = load_array{'abc', 'def', 'ghi jkl', 'mno'}
  Line_width = App.screen.width
  Cursor1 = {line=3, pos=6}
  Screen_top1 = {line=3, pos=5}
  Screen_bottom1 = {}
  App.draw()
  local y = Margin_top
  App.screen.check(y, 'jkl', 'F - test_up_arrow_scrolls_up_by_one_screen_line/baseline/screen:1')
  y = y + Line_height
  App.screen.check(y, 'mno', 'F - test_up_arrow_scrolls_up_by_one_screen_line/baseline/screen:2')
  -- after hitting the up arrow the screen scrolls up to first screen line
  App.run_after_keychord('up')
  y = Margin_top
  App.screen.check(y, 'ghi ', 'F - test_up_arrow_scrolls_up_by_one_screen_line/screen:1')
  y = y + Line_height
  App.screen.check(y, 'jkl', 'F - test_up_arrow_scrolls_up_by_one_screen_line/screen:2')
  y = y + Line_height
  App.screen.check(y, 'mno', 'F - test_up_arrow_scrolls_up_by_one_screen_line/screen:3')
  check_eq(Screen_top1.line, 3, 'F - test_up_arrow_scrolls_up_by_one_screen_line/screen_top')
  check_eq(Screen_top1.pos, 1, 'F - test_up_arrow_scrolls_up_by_one_screen_line/screen_top')
  check_eq(Cursor1.line, 3, 'F - test_up_arrow_scrolls_up_by_one_screen_line/cursor:line')
  check_eq(Cursor1.pos, 1, 'F - test_up_arrow_scrolls_up_by_one_screen_line/cursor:pos')
end
function test_up_arrow_scrolls_up_to_final_screen_line()
  io.write('\ntest_up_arrow_scrolls_up_to_final_screen_line')
  -- display lines starting just after a long line
  App.screen.init{width=25+30, height=60}
  Lines = load_array{'abc def', 'ghi', 'jkl', 'mno'}
  Line_width = App.screen.width
  Cursor1 = {line=2, pos=1}
  Screen_top1 = {line=2, pos=1}
  Screen_bottom1 = {}
  App.draw()
  local y = Margin_top
  App.screen.check(y, 'ghi', 'F - test_up_arrow_scrolls_up_to_final_screen_line/baseline/screen:1')
  y = y + Line_height
  App.screen.check(y, 'jkl', 'F - test_up_arrow_scrolls_up_to_final_screen_line/baseline/screen:2')
  y = y + Line_height
  App.screen.check(y, 'mno', 'F - test_up_arrow_scrolls_up_to_final_screen_line/baseline/screen:3')
  -- after hitting the up arrow the screen scrolls up to final screen line of previous line
  App.run_after_keychord('up')
  y = Margin_top
  App.screen.check(y, 'def', 'F - test_up_arrow_scrolls_up_to_final_screen_line/screen:1')
  y = y + Line_height
  App.screen.check(y, 'ghi', 'F - test_up_arrow_scrolls_up_to_final_screen_line/screen:2')
  y = y + Line_height
  App.screen.check(y, 'jkl', 'F - test_up_arrow_scrolls_up_to_final_screen_line/screen:3')
  check_eq(Screen_top1.line, 1, 'F - test_up_arrow_scrolls_up_to_final_screen_line/screen_top')
  check_eq(Screen_top1.pos, 5, 'F - test_up_arrow_scrolls_up_to_final_screen_line/screen_top')
  check_eq(Cursor1.line, 1, 'F - test_up_arrow_scrolls_up_to_final_screen_line/cursor:line')
  check_eq(Cursor1.pos, 5, 'F - test_up_arrow_scrolls_up_to_final_screen_line/cursor:pos')
end
function test_up_arrow_scrolls_up_to_empty_line()
  io.write('\ntest_up_arrow_scrolls_up_to_empty_line')
  -- display a screenful of text with an empty line just above it outside the screen
  App.screen.init{width=120, height=60}
  Lines = load_array{'', 'abc', 'def', 'ghi', 'jkl'}
  Line_width = 120
  Cursor1 = {line=2, pos=1}
  Screen_top1 = {line=2, pos=1}
  Screen_bottom1 = {}
  App.draw()
  local y = Margin_top
  App.screen.check(y, 'abc', 'F - test_up_arrow_scrolls_up_to_empty_line/baseline/screen:1')
  y = y + Line_height
  App.screen.check(y, 'def', 'F - test_up_arrow_scrolls_up_to_empty_line/baseline/screen:2')
  y = y + Line_height
  App.screen.check(y, 'ghi', 'F - test_up_arrow_scrolls_up_to_empty_line/baseline/screen:3')
  -- after hitting the up arrow the screen scrolls up by one line
  App.run_after_keychord('up')
  check_eq(Screen_top1.line, 1, 'F - test_up_arrow_scrolls_up_to_empty_line/screen_top')
  check_eq(Cursor1.line, 1, 'F - test_up_arrow_scrolls_up_to_empty_line/cursor')
  y = Margin_top
  -- empty first line
  y = y + Line_height
  App.screen.check(y, 'abc', 'F - test_up_arrow_scrolls_up_to_empty_line/screen:2')
  y = y + Line_height
  App.screen.check(y, 'def', 'F - test_up_arrow_scrolls_up_to_empty_line/screen:3')
end
function test_pageup()
  io.write('\ntest_pageup')
  App.screen.init{width=120, height=45}
  Lines = load_array{'abc', 'def', 'ghi'}
  Line_width = App.screen.width
  Cursor1 = {line=2, pos=1}
  Screen_top1 = {line=2, pos=1}
  Screen_bottom1 = {}
  -- initially the last two lines are displayed
  App.draw()
  local y = Margin_top
  App.screen.check(y, 'def', 'F - test_pageup/baseline/screen:1')
  y = y + Line_height
  App.screen.check(y, 'ghi', 'F - test_pageup/baseline/screen:2')
  -- after pageup the cursor goes to first line
  App.run_after_keychord('pageup')
  check_eq(Screen_top1.line, 1, 'F - test_pageup/screen_top')
  check_eq(Cursor1.line, 1, 'F - test_pageup/cursor')
  y = Margin_top
  App.screen.check(y, 'abc', 'F - test_pageup/screen:1')
  y = y + Line_height
  App.screen.check(y, 'def', 'F - test_pageup/screen:2')
end
function test_pageup_scrolls_up_by_screen_line()
  io.write('\ntest_pageup_scrolls_up_by_screen_line')
  -- display the first three lines with the cursor on the bottom line
  App.screen.init{width=25+30, height=60}
  Lines = load_array{'abc def', 'ghi', 'jkl', 'mno'}
  Line_width = App.screen.width
  Cursor1 = {line=2, pos=1}
  Screen_top1 = {line=2, pos=1}
  Screen_bottom1 = {}
  App.draw()
  local y = Margin_top
  App.screen.check(y, 'ghi', 'F - test_pageup_scrolls_up_by_screen_line/baseline/screen:1')
  y = y + Line_height
  App.screen.check(y, 'jkl', 'F - test_pageup_scrolls_up_by_screen_line/baseline/screen:2')
  y = y + Line_height
  App.screen.check(y, 'mno', 'F - test_pageup_scrolls_up_by_screen_line/baseline/screen:3')  -- line wrapping includes trailing whitespace
  -- after hitting the page-up key the screen scrolls up to top
  App.run_after_keychord('pageup')
  check_eq(Screen_top1.line, 1, 'F - test_pageup_scrolls_up_by_screen_line/screen_top')
  check_eq(Cursor1.line, 1, 'F - test_pageup_scrolls_up_by_screen_line/cursor:line')
  check_eq(Cursor1.pos, 1, 'F - test_pageup_scrolls_up_by_screen_line/cursor:pos')
  y = Margin_top
  App.screen.check(y, 'abc ', 'F - test_pageup_scrolls_up_by_screen_line/screen:1')
  y = y + Line_height
  App.screen.check(y, 'def', 'F - test_pageup_scrolls_up_by_screen_line/screen:2')
  y = y + Line_height
  App.screen.check(y, 'ghi', 'F - test_pageup_scrolls_up_by_screen_line/screen:3')
end
function test_pageup_scrolls_up_from_middle_screen_line()
  io.write('\ntest_pageup_scrolls_up_from_middle_screen_line')
  -- display a few lines starting from the middle of a line (Cursor1.pos > 1)
  App.screen.init{width=25+30, height=60}
  Lines = load_array{'abc def', 'ghi jkl', 'mno'}
  Line_width = App.screen.width
  Cursor1 = {line=2, pos=5}
  Screen_top1 = {line=2, pos=5}
  Screen_bottom1 = {}
  App.draw()
  local y = Margin_top
  App.screen.check(y, 'jkl', 'F - test_pageup_scrolls_up_from_middle_screen_line/baseline/screen:2')
  y = y + Line_height
  App.screen.check(y, 'mno', 'F - test_pageup_scrolls_up_from_middle_screen_line/baseline/screen:3')  -- line wrapping includes trailing whitespace
  -- after hitting the page-up key the screen scrolls up to top
  App.run_after_keychord('pageup')
  check_eq(Screen_top1.line, 1, 'F - test_pageup_scrolls_up_from_middle_screen_line/screen_top')
  check_eq(Cursor1.line, 1, 'F - test_pageup_scrolls_up_from_middle_screen_line/cursor:line')
  check_eq(Cursor1.pos, 1, 'F - test_pageup_scrolls_up_from_middle_screen_line/cursor:pos')
  y = Margin_top
  App.screen.check(y, 'abc ', 'F - test_pageup_scrolls_up_from_middle_screen_line/screen:1')
  y = y + Line_height
  App.screen.check(y, 'def', 'F - test_pageup_scrolls_up_from_middle_screen_line/screen:2')
  y = y + Line_height
  App.screen.check(y, 'ghi ', 'F - test_pageup_scrolls_up_from_middle_screen_line/screen:3')
end
function test_enter_on_bottom_line_scrolls_down()
  io.write('\ntest_enter_on_bottom_line_scrolls_down')
  -- display a few lines with cursor on bottom line
  App.screen.init{width=25+30, height=60}
  Lines = load_array{'abc', 'def', 'ghi', 'jkl'}
  Line_width = App.screen.width
  Cursor1 = {line=3, pos=2}
  Screen_top1 = {line=1, pos=1}
  Screen_bottom1 = {}
  App.draw()
  local y = Margin_top
  App.screen.check(y, 'abc', 'F - test_enter_on_bottom_line_scrolls_down/baseline/screen:1')
  y = y + Line_height
  App.screen.check(y, 'def', 'F - test_enter_on_bottom_line_scrolls_down/baseline/screen:2')
  y = y + Line_height
  App.screen.check(y, 'ghi', 'F - test_enter_on_bottom_line_scrolls_down/baseline/screen:3')
  -- after hitting the enter key the screen scrolls down
  App.run_after_keychord('return')
  check_eq(Screen_top1.line, 2, 'F - test_enter_on_bottom_line_scrolls_down/screen_top')
  check_eq(Cursor1.line, 4, 'F - test_enter_on_bottom_line_scrolls_down/cursor:line')
  check_eq(Cursor1.pos, 1, 'F - test_enter_on_bottom_line_scrolls_down/cursor:pos')
  y = Margin_top
  App.screen.check(y, 'def', 'F - test_enter_on_bottom_line_scrolls_down/screen:1')
  y = y + Line_height
  App.screen.check(y, 'g', 'F - test_enter_on_bottom_line_scrolls_down/screen:2')
  y = y + Line_height
  App.screen.check(y, 'hi', 'F - test_enter_on_bottom_line_scrolls_down/screen:3')
end
function test_enter_on_final_line_avoids_scrolling_down_when_not_at_bottom()
  io.write('\ntest_enter_on_final_line_avoids_scrolling_down_when_not_at_bottom')
  -- display just the bottom line on screen
  App.screen.init{width=25+30, height=60}
  Lines = load_array{'abc', 'def', 'ghi', 'jkl'}
  Line_width = App.screen.width
  Cursor1 = {line=4, pos=2}
  Screen_top1 = {line=4, pos=1}
  Screen_bottom1 = {}
  App.draw()
  local y = Margin_top
  App.screen.check(y, 'jkl', 'F - test_enter_on_final_line_avoids_scrolling_down_when_not_at_bottom/baseline/screen:1')
  -- after hitting the enter key the screen does not scroll down
  App.run_after_keychord('return')
  check_eq(Screen_top1.line, 4, 'F - test_enter_on_final_line_avoids_scrolling_down_when_not_at_bottom/screen_top')
  check_eq(Cursor1.line, 5, 'F - test_enter_on_final_line_avoids_scrolling_down_when_not_at_bottom/cursor:line')
  check_eq(Cursor1.pos, 1, 'F - test_enter_on_final_line_avoids_scrolling_down_when_not_at_bottom/cursor:pos')
  y = Margin_top
  App.screen.check(y, 'j', 'F - test_enter_on_final_line_avoids_scrolling_down_when_not_at_bottom/screen:1')
  y = y + Line_height
  App.screen.check(y, 'kl', 'F - test_enter_on_final_line_avoids_scrolling_down_when_not_at_bottom/screen:2')
end
function test_position_cursor_on_recently_edited_wrapping_line()
  -- draw a line wrapping over 2 screen lines
  io.write('\ntest_position_cursor_on_recently_edited_wrapping_line')
  App.screen.init{width=120, height=200}
  Lines = load_array{'abc def ghi jkl mno pqr ', 'xyz'}
  Line_width = 100
  Cursor1 = {line=1, pos=25}
  Screen_top1 = {line=1, pos=1}
  Screen_bottom1 = {}
  App.draw()
  local y = Margin_top
  -- I don't understand why 120px fits so much on a fake screen, but whatever..
  App.screen.check(y, 'abc def ghi ', 'F - test_position_cursor_on_recently_edited_wrapping_line/baseline1/screen:1')
  y = y + Line_height
  App.screen.check(y, 'jkl mno pqr ', 'F - test_position_cursor_on_recently_edited_wrapping_line/baseline1/screen:2')
  y = y + Line_height
  App.screen.check(y, 'xyz', 'F - test_position_cursor_on_recently_edited_wrapping_line/baseline1/screen:3')
  -- add to the line until it's wrapping over 3 screen lines
  App.run_after_textinput('s')
  App.run_after_textinput('t')
  App.run_after_textinput('u')
  check_eq(Cursor1.pos, 28, 'F - test_move_cursor_using_mouse/cursor:pos')
  y = Margin_top
  App.screen.check(y, 'abc def ghi ', 'F - test_position_cursor_on_recently_edited_wrapping_line/baseline2/screen:1')
  y = y + Line_height
  App.screen.check(y, 'jkl mno pqr ', 'F - test_position_cursor_on_recently_edited_wrapping_line/baseline2/screen:2')
  y = y + Line_height
  App.screen.check(y, 'stu', 'F - test_position_cursor_on_recently_edited_wrapping_line/baseline2/screen:3')
  -- try to move the cursor earlier in the third screen line by clicking the mouse
  local screen_left_margin = 25  -- pixels
  App.run_after_mouserelease(screen_left_margin+8,Margin_top+Line_height*2+5, '1')
  -- cursor should move
  check_eq(Cursor1.line, 1, 'F - test_move_cursor_using_mouse/cursor:line')
  check_eq(Cursor1.pos, 26, 'F - test_move_cursor_using_mouse/cursor:pos')
end
function test_backspace_can_scroll_up()
  io.write('\ntest_backspace_can_scroll_up')
  -- display the lines 2/3/4 with the cursor on line 2
  App.screen.init{width=120, height=60}
  Lines = load_array{'abc', 'def', 'ghi', 'jkl'}
  Line_width = 120
  Cursor1 = {line=2, pos=1}
  Screen_top1 = {line=2, pos=1}
  Screen_bottom1 = {}
  App.draw()
  local y = Margin_top
  App.screen.check(y, 'def', 'F - test_backspace_can_scroll_up/baseline/screen:1')
  y = y + Line_height
  App.screen.check(y, 'ghi', 'F - test_backspace_can_scroll_up/baseline/screen:2')
  y = y + Line_height
  App.screen.check(y, 'jkl', 'F - test_backspace_can_scroll_up/baseline/screen:3')
  -- after hitting backspace the screen scrolls up by one line
  App.run_after_keychord('backspace')
  check_eq(Screen_top1.line, 1, 'F - test_backspace_can_scroll_up/screen_top')
  check_eq(Cursor1.line, 1, 'F - test_backspace_can_scroll_up/cursor')
  y = Margin_top
  App.screen.check(y, 'abcdef', 'F - test_backspace_can_scroll_up/screen:1')
  y = y + Line_height
  App.screen.check(y, 'ghi', 'F - test_backspace_can_scroll_up/screen:2')
  y = y + Line_height
  App.screen.check(y, 'jkl', 'F - test_backspace_can_scroll_up/screen:3')
end
function test_backspace_can_scroll_up_screen_line()
  io.write('\ntest_backspace_can_scroll_up_screen_line')
  -- display lines starting from second screen line of a line
  App.screen.init{width=25+30, height=60}
  Lines = load_array{'abc', 'def', 'ghi jkl', 'mno'}
  Line_width = App.screen.width
  Cursor1 = {line=3, pos=5}
  Screen_top1 = {line=3, pos=5}
  Screen_bottom1 = {}
  App.draw()
  local y = Margin_top
  App.screen.check(y, 'jkl', 'F - test_backspace_can_scroll_up_screen_line/baseline/screen:1')
  y = y + Line_height
  App.screen.check(y, 'mno', 'F - test_backspace_can_scroll_up_screen_line/baseline/screen:2')
  -- after hitting backspace the screen scrolls up by one screen line
  App.run_after_keychord('backspace')
  y = Margin_top
  App.screen.check(y, 'ghijk', 'F - test_backspace_can_scroll_up_screen_line/screen:1')
  y = y + Line_height
  App.screen.check(y, 'l', 'F - test_backspace_can_scroll_up_screen_line/screen:2')
  y = y + Line_height
  App.screen.check(y, 'mno', 'F - test_backspace_can_scroll_up_screen_line/screen:3')
  check_eq(Screen_top1.line, 3, 'F - test_backspace_can_scroll_up_screen_line/screen_top')
  check_eq(Screen_top1.pos, 1, 'F - test_backspace_can_scroll_up_screen_line/screen_top')
  check_eq(Cursor1.line, 3, 'F - test_backspace_can_scroll_up_screen_line/cursor:line')
  check_eq(Cursor1.pos, 4, 'F - test_backspace_can_scroll_up_screen_line/cursor:pos')
end
-- some tests for operating over selections created using Shift- chords
-- we're just testing delete_selection, and it works the same for all keys
function test_backspace_over_selection()
  io.write('\ntest_backspace_over_selection')
  -- select just one character within a line with cursor before selection
  App.screen.init{width=25+30, height=60}
  Lines = load_array{'abc', 'def', 'ghi', 'jkl', 'mno'}
  Line_width = App.screen.width
  Cursor1 = {line=1, pos=1}
  Selection1 = {line=1, pos=2}
  -- backspace deletes the selected character, even though it's after the cursor
  App.run_after_keychord('backspace')
  check_eq(Lines[1].data, 'bc', "F - test_backspace_over_selection/data")
  -- cursor (remains) at start of selection
  check_eq(Cursor1.line, 1, "F - test_backspace_over_selection/cursor:line")
  check_eq(Cursor1.pos, 1, "F - test_backspace_over_selection/cursor:pos")
  -- selection is cleared
  check_nil(Selection1.line, "F - test_backspace_over_selection/selection")
end
function test_backspace_over_selection_reverse()
  io.write('\ntest_backspace_over_selection_reverse')
  -- select just one character within a line with cursor after selection
  App.screen.init{width=25+30, height=60}
  Lines = load_array{'abc', 'def', 'ghi', 'jkl', 'mno'}
  Line_width = App.screen.width
  Cursor1 = {line=1, pos=2}
  Selection1 = {line=1, pos=1}
  -- backspace deletes the selected character
  App.run_after_keychord('backspace')
  check_eq(Lines[1].data, 'bc', "F - test_backspace_over_selection_reverse/data")
  -- cursor moves to start of selection
  check_eq(Cursor1.line, 1, "F - test_backspace_over_selection_reverse/cursor:line")
  check_eq(Cursor1.pos, 1, "F - test_backspace_over_selection_reverse/cursor:pos")
  -- selection is cleared
  check_nil(Selection1.line, "F - test_backspace_over_selection_reverse/selection")
end
function test_backspace_over_multiple_lines()
  io.write('\ntest_backspace_over_multiple_lines')
  -- select just one character within a line with cursor after selection
  App.screen.init{width=25+30, height=60}
  Lines = load_array{'abc', 'def', 'ghi', 'jkl', 'mno'}
  Line_width = App.screen.width
  Cursor1 = {line=1, pos=2}
  Selection1 = {line=4, pos=2}
  -- backspace deletes the region and joins the remaining portions of lines on either side
  App.run_after_keychord('backspace')
  check_eq(Lines[1].data, 'akl', "F - test_backspace_over_multiple_lines/data:1")
  check_eq(Lines[2].data, 'mno', "F - test_backspace_over_multiple_lines/data:2")
  -- cursor remains at start of selection
  check_eq(Cursor1.line, 1, "F - test_backspace_over_multiple_lines/cursor:line")
  check_eq(Cursor1.pos, 2, "F - test_backspace_over_multiple_lines/cursor:pos")
  -- selection is cleared
  check_nil(Selection1.line, "F - test_backspace_over_multiple_lines/selection")
end
function test_backspace_to_end_of_line()
  io.write('\ntest_backspace_to_end_of_line')
  -- select region from cursor to end of line
  App.screen.init{width=25+30, height=60}
  Lines = load_array{'abc', 'def', 'ghi', 'jkl', 'mno'}
  Line_width = App.screen.width
  Cursor1 = {line=1, pos=2}
  Selection1 = {line=1, pos=4}
  -- backspace deletes rest of line without joining to any other line
  App.run_after_keychord('backspace')
  check_eq(Lines[1].data, 'a', "F - test_backspace_to_start_of_line/data:1")
  check_eq(Lines[2].data, 'def', "F - test_backspace_to_start_of_line/data:2")
  -- cursor remains at start of selection
  check_eq(Cursor1.line, 1, "F - test_backspace_to_start_of_line/cursor:line")
  check_eq(Cursor1.pos, 2, "F - test_backspace_to_start_of_line/cursor:pos")
  -- selection is cleared
  check_nil(Selection1.line, "F - test_backspace_to_start_of_line/selection")
end
function test_backspace_to_start_of_line()
  io.write('\ntest_backspace_to_start_of_line')
  -- select region from cursor to start of line
  App.screen.init{width=25+30, height=60}
  Lines = load_array{'abc', 'def', 'ghi', 'jkl', 'mno'}
  Line_width = App.screen.width
  Cursor1 = {line=2, pos=1}
  Selection1 = {line=2, pos=3}
  -- backspace deletes beginning of line without joining to any other line
  App.run_after_keychord('backspace')
  check_eq(Lines[1].data, 'abc', "F - test_backspace_to_start_of_line/data:1")
  check_eq(Lines[2].data, 'f', "F - test_backspace_to_start_of_line/data:2")
  -- cursor remains at start of selection
  check_eq(Cursor1.line, 2, "F - test_backspace_to_start_of_line/cursor:line")
  check_eq(Cursor1.pos, 1, "F - test_backspace_to_start_of_line/cursor:pos")
  -- selection is cleared
  check_nil(Selection1.line, "F - test_backspace_to_start_of_line/selection")
end
function test_undo_insert_text()
  io.write('\ntest_undo_insert_text')
  App.screen.init{width=120, height=60}
  Lines = load_array{'abc', 'def', 'xyz'}
  Line_width = App.screen.width
  Cursor1 = {line=2, pos=4}
  Screen_top1 = {line=1, pos=1}
  Screen_bottom1 = {}
  -- insert a character
  App.run_after_textinput('g')
  check_eq(Cursor1.line, 2, 'F - test_undo_insert_text/baseline/cursor:line')
  check_eq(Cursor1.pos, 5, 'F - test_undo_insert_text/baseline/cursor:pos')
  check_nil(Selection1.line, 'F - test_undo_insert_text/baseline/selection:line')
  check_nil(Selection1.pos, 'F - test_undo_insert_text/baseline/selection:pos')
  local y = Margin_top
  App.screen.check(y, 'abc', 'F - test_undo_insert_text/baseline/screen:1')
  y = y + Line_height
  App.screen.check(y, 'defg', 'F - test_undo_insert_text/baseline/screen:2')
  y = y + Line_height
  App.screen.check(y, 'xyz', 'F - test_undo_insert_text/baseline/screen:3')
  -- undo
  App.run_after_keychord('C-z')
  check_eq(Cursor1.line, 2, 'F - test_undo_insert_text/cursor:line')
  check_eq(Cursor1.pos, 4, 'F - test_undo_insert_text/cursor:pos')
  check_nil(Selection1.line, 'F - test_undo_insert_text/selection:line')
  check_nil(Selection1.pos, 'F - test_undo_insert_text/selection:pos')
  y = Margin_top
  App.screen.check(y, 'abc', 'F - test_undo_insert_text/screen:1')
  y = y + Line_height
  App.screen.check(y, 'def', 'F - test_undo_insert_text/screen:2')
  y = y + Line_height
  App.screen.check(y, 'xyz', 'F - test_undo_insert_text/screen:3')
end
function test_undo_delete_text()
  io.write('\ntest_undo_delete_text')
  App.screen.init{width=120, height=60}
  Lines = load_array{'abc', 'defg', 'xyz'}
  Line_width = App.screen.width
  Cursor1 = {line=2, pos=5}
  Screen_top1 = {line=1, pos=1}
  Screen_bottom1 = {}
  -- delete a character
  App.run_after_keychord('backspace')
  check_eq(Cursor1.line, 2, 'F - test_undo_delete_text/baseline/cursor:line')
  check_eq(Cursor1.pos, 4, 'F - test_undo_delete_text/baseline/cursor:pos')
  check_nil(Selection1.line, 'F - test_undo_delete_text/baseline/selection:line')
  check_nil(Selection1.pos, 'F - test_undo_delete_text/baseline/selection:pos')
  local y = Margin_top
  App.screen.check(y, 'abc', 'F - test_undo_delete_text/baseline/screen:1')
  y = y + Line_height
  App.screen.check(y, 'def', 'F - test_undo_delete_text/baseline/screen:2')
  y = y + Line_height
  App.screen.check(y, 'xyz', 'F - test_undo_delete_text/baseline/screen:3')
  -- undo
--?   -- after undo, the backspaced key is selected
  App.run_after_keychord('C-z')
  check_eq(Cursor1.line, 2, 'F - test_undo_delete_text/cursor:line')
  check_eq(Cursor1.pos, 5, 'F - test_undo_delete_text/cursor:pos')
  check_nil(Selection1.line, 'F - test_undo_delete_text/selection:line')
  check_nil(Selection1.pos, 'F - test_undo_delete_text/selection:pos')
--?   check_eq(Selection1.line, 2, 'F - test_undo_delete_text/selection:line')
--?   check_eq(Selection1.pos, 4, 'F - test_undo_delete_text/selection:pos')
  y = Margin_top
  App.screen.check(y, 'abc', 'F - test_undo_delete_text/screen:1')
  y = y + Line_height
  App.screen.check(y, 'defg', 'F - test_undo_delete_text/screen:2')
  y = y + Line_height
  App.screen.check(y, 'xyz', 'F - test_undo_delete_text/screen:3')
end

Replacement in text.lua at line 1 [9.1]

B:BD[9.1] → [9.2:33]

-- primitives for editing text

[9.1]

[9.33]

-- text editor, particularly text drawing, horizontal wrap, vertical scrolling

Insertion in text.lua at line 6 [9.1]
[10.2775]
[10.2775]
```
require 'search'
require 'select'
```
Insertion in text.lua at line 9 [9.1]
[10.2790]
[11.1567]
```
require 'text_tests'
```

Deletion in text.lua at line 109 [9.1]

B:BD[11.2728] → [12.764:797]

B:BD[12.797] → [13.472:498]

∅:D[13.498] → [12.831:1313]

B:BD[12.831] → [12.831:1313]

B:BD[12.1313] → [13.499:539]

∅:D[13.539] → [12.1362:1497]

B:BD[12.1362] → [12.1362:1497]

B:BD[12.1497] → [13.540:607]

∅:D[13.607] → [12.1581:2104]

B:BD[12.1581] → [12.1581:2104]

B:BD[12.2104] → [14.2:130]

B:BD[14.130] → [7.2:194]

∅:D[7.194] → [14.220:709]

B:BD[14.220] → [14.220:709]

∅:D[14.709] → [12.2104:2232]

B:BD[12.2104] → [12.2104:2232]

B:BD[12.2232] → [14.710:941]

B:BD[14.941] → [7.195:387]

∅:D[7.387] → [12.2322:2539]

B:BD[12.2322] → [12.2322:2539]

∅:D[12.2539] → [15.1067:1068]

B:BD[11.2728] → [15.1067:1068]

B:BD[15.1068] → [14.942:1240]

B:BD[14.1240] → [6.2:270]

∅:D[6.270] → [15.1224:1556]

B:BD[15.1224] → [15.1224:1556]

B:BD[15.1556] → [6.271:409]

∅:D[6.409] → [15.1601:2613]

B:BD[15.1601] → [15.1601:2613]

B:BD[15.2613] → [6.410:826]

∅:D[6.826] → [15.2613:2619]

B:BD[15.2613] → [15.2613:2619]

B:BD[15.2619] → [6.827:872]

∅:D[6.872] → [15.2619:2624]

B:BD[15.2619] → [15.2619:2624]

B:BD[15.2624] → [6.873:1098]

∅:D[6.1098] → [15.2624:2657]

B:BD[15.2624] → [15.2624:2657]

B:BD[15.2657] → [16.920:1173]

∅:D[16.1173] → [15.2657:3719]

B:BD[15.2657] → [15.2657:3719]

∅:D[15.3719] → [17.100:101]

B:BD[11.2796] → [17.100:101]

B:BD[17.101] → [18.1:850]


function Text.draw_search_bar()
  local h = Line_height+2
  local y = App.screen.height-h
  love.graphics.setColor(0.9,0.9,0.9)
  love.graphics.rectangle('fill', 0, y-10, App.screen.width-1, h+8)
  love.graphics.setColor(0.6,0.6,0.6)
  love.graphics.line(0, y-10, App.screen.width-1, y-10)
  love.graphics.setColor(1,1,1)
  love.graphics.rectangle('fill', 20, y-6, App.screen.width-40, h+2, 2,2)
  love.graphics.setColor(0.6,0.6,0.6)
  love.graphics.rectangle('line', 20, y-6, App.screen.width-40, h+2, 2,2)
  love.graphics.setColor(0,0,0)
  App.screen.print(Search_term, 25,y-5)
  love.graphics.setColor(1,0,0)
  if Search_text == nil then
    Search_text = App.newText(love.graphics.getFont(), Search_term)
  end
  love.graphics.circle('fill', 25+App.width(Search_text),y-5+h, 2)
  love.graphics.setColor(0,0,0)
end
function Text.search_next()
  -- search current line
  local pos = Lines[Cursor1.line].data:find(Search_term, Cursor1.pos)
  if pos then
    Cursor1.pos = pos
  end
  if pos == nil then
    for i=Cursor1.line+1,#Lines do
      pos = Lines[i].data:find(Search_term)
      if pos then
        Cursor1.line = i
        Cursor1.pos = pos
        break
      end
    end
  end
  if pos == nil then
    -- wrap around
    for i=1,Cursor1.line-1 do
      pos = Lines[i].data:find(Search_term)
      if pos then
        Cursor1.line = i
        Cursor1.pos = pos
        break
      end
    end
  end
  if pos == nil then
    Cursor1.line = Search_backup.cursor.line
    Cursor1.pos = Search_backup.cursor.pos
    Screen_top1.line = Search_backup.screen_top.line
    Screen_top1.pos = Search_backup.screen_top.pos
  end
  if Text.lt1(Cursor1, Screen_top1) or Text.lt1(Screen_bottom1, Cursor1) then
    Screen_top1.line = Cursor1.line
    local _, pos = Text.pos_at_start_of_cursor_screen_line()
    Screen_top1.pos = pos
  end
end
function Text.search_previous()
  -- search current line
  local pos = rfind(Lines[Cursor1.line].data, Search_term, Cursor1.pos)
  if pos then
    Cursor1.pos = pos
  end
  if pos == nil then
    for i=Cursor1.line-1,1,-1 do
      pos = rfind(Lines[i].data, Search_term)
      if pos then
        Cursor1.line = i
        Cursor1.pos = pos
        break
      end
    end
  end
  if pos == nil then
    -- wrap around
    for i=#Lines,Cursor1.line+1,-1 do
      pos = rfind(Lines[i].data, Search_term)
      if pos then
        Cursor1.line = i
        Cursor1.pos = pos
        break
      end
    end
  end
  if pos == nil then
    Cursor1.line = Search_backup.cursor.line
    Cursor1.pos = Search_backup.cursor.pos
    Screen_top1.line = Search_backup.screen_top.line
    Screen_top1.pos = Search_backup.screen_top.pos
  end
  if Text.lt1(Cursor1, Screen_top1) or Text.lt1(Screen_bottom1, Cursor1) then
    Screen_top1.line = Cursor1.line
    local _, pos = Text.pos_at_start_of_cursor_screen_line()
    Screen_top1.pos = pos
  end
end
function rfind(s, pat, i)
  local rs = s:reverse()
  local rpat = pat:reverse()
  if i == nil then i = #s end
  local ri = #s - i + 1
  local rendpos = rs:find(rpat, ri)
  if rendpos == nil then return nil end
  local endpos = #s - rendpos + 1
  assert (endpos >= #pat)
  return endpos-#pat+1
end
-- Return any intersection of the region from Selection1 to Cursor1 (or
-- current mouse, if mouse is pressed; or recent mouse if mouse is pressed and
-- currently over a drawing) with the region between {line=line_index, pos=apos}
-- and {line=line_index, pos=bpos}.
-- apos must be less than bpos. However Selection1 and Cursor1 can be in any order.
-- Result: positions spos,epos between apos,bpos.
function Text.clip_selection(line_index, apos, bpos)
  if Selection1.line == nil then return nil,nil end
  -- min,max = sorted(Selection1,Cursor1)
  local minl,minp = Selection1.line,Selection1.pos
  local maxl,maxp
  if love.mouse.isDown('1') then
    maxl,maxp = Text.mouse_pos()
  else
    maxl,maxp = Cursor1.line,Cursor1.pos
  end
  if minl > maxl then
    minl,maxl = maxl,minl
    minp,maxp = maxp,minp
  elseif minl == maxl then
    if minp > maxp then
      minp,maxp = maxp,minp
    end
  end
  -- check if intervals are disjoint
  if line_index < minl then return nil,nil end
  if line_index > maxl then return nil,nil end
  if line_index == minl and bpos <= minp then return nil,nil end
  if line_index == maxl and apos >= maxp then return nil,nil end
  -- compare bounds more carefully (start inclusive, end exclusive)
  local a_ge = Text.le1({line=minl, pos=minp}, {line=line_index, pos=apos})
  local b_lt = Text.lt1({line=line_index, pos=bpos}, {line=maxl, pos=maxp})
--?   print(minl,line_index,maxl, '--', minp,apos,bpos,maxp, '--', a_ge,b_lt)
  if a_ge and b_lt then
    -- fully contained
    return apos,bpos
  elseif a_ge then
    assert(maxl == line_index)
    return apos,maxp
  elseif b_lt then
    assert(minl == line_index)
    return minp,bpos
  else
    assert(minl == maxl and minl == line_index)
    return minp,maxp
  end
end
-- inefficient for some reason, so don't do it on every frame
function Text.mouse_pos()
  local time = love.timer.getTime()
  if Recent_mouse.time and Recent_mouse.time > time-0.1 then
    return Recent_mouse.line, Recent_mouse.pos
  end
  Recent_mouse.time = time
  local line,pos = Text.to_pos(love.mouse.getX(), love.mouse.getY())
  if line then
    Recent_mouse.line = line
    Recent_mouse.pos = pos
  end
  return Recent_mouse.line, Recent_mouse.pos
end
function Text.to_pos(x,y)
  for line_index,line in ipairs(Lines) do
    if line.mode == 'text' then
      if Text.in_line(line, x,y) then
        return line_index, Text.to_pos_on_line(line, x,y)
      end
    end
  end
end
function Text.delete_selection()
  local minl,maxl = minmax(Selection1.line, Cursor1.line)
  local before = snapshot(minl, maxl)
  Text.delete_selection_without_undo()
  record_undo_event({before=before, after=snapshot(Cursor1.line)})
end
function Text.delete_selection_without_undo()
  if Selection1.line == nil then return end
  -- min,max = sorted(Selection1,Cursor1)
  local minl,minp = Selection1.line,Selection1.pos
  local maxl,maxp = Cursor1.line,Cursor1.pos
  if minl > maxl then
    minl,maxl = maxl,minl
    minp,maxp = maxp,minp
  elseif minl == maxl then
    if minp > maxp then
      minp,maxp = maxp,minp
    end
  end
  -- update Cursor1 and Selection1
  Cursor1.line = minl
  Cursor1.pos = minp
  Selection1 = {}
  -- delete everything between min (inclusive) and max (exclusive)
  Lines[minl].fragments = nil
  Lines[minl].screen_line_starting_pos = nil
  local min_offset = utf8.offset(Lines[minl].data, minp)
  local max_offset = utf8.offset(Lines[maxl].data, maxp)
  if minl == maxl then
--?     print('minl == maxl')
    Lines[minl].data = Lines[minl].data:sub(1, min_offset-1)..Lines[minl].data:sub(max_offset)
    return
  end
  assert(minl < maxl)
  local rhs = Lines[maxl].data:sub(max_offset)
  for i=maxl,minl+1,-1 do
    table.remove(Lines, i)
  end
  Lines[minl].data = Lines[minl].data:sub(1, min_offset-1)..rhs
end
function Text.selection()
  if Selection1.line == nil then return end
  -- min,max = sorted(Selection1,Cursor1)
  local minl,minp = Selection1.line,Selection1.pos
  local maxl,maxp = Cursor1.line,Cursor1.pos
  if minl > maxl then
    minl,maxl = maxl,minl
    minp,maxp = maxp,minp
  elseif minl == maxl then
    if minp > maxp then
      minp,maxp = maxp,minp
    end
  end
  local min_offset = utf8.offset(Lines[minl].data, minp)
  local max_offset = utf8.offset(Lines[maxl].data, maxp)
  if minl == maxl then
    return Lines[minl].data:sub(min_offset, max_offset-1)
  end
  assert(minl < maxl)
  local result = Lines[minl].data:sub(min_offset)..'\n'
  for i=minl+1,maxl-1 do
    if Lines[i].mode == 'text' then
      result = result..Lines[i].data..'\n'
    end
  end
  result = result..Lines[maxl].data:sub(1, max_offset-1)
  return result
end

Deletion in text.lua at line 110 [9.1]

B:BD[18.851] → [18.851:962]

function Text.cut_selection()
  local result = Text.selection()
  Text.delete_selection()
  return result
end

Deletion in text.lua at line 118 [9.1]

B:BD[19.42] → [20.111:137]

B:BD[20.137] → [2.1:32]

∅:D[2.32] → [20.137:219]

∅:D[21.197] → [20.137:219]

B:BD[20.137] → [20.137:219]

B:BD[20.219] → [22.265:297]

∅:D[22.297] → [20.238:320]

B:BD[20.238] → [20.238:320]

B:BD[20.331] → [20.331:344]

B:BD[20.344] → [23.2:25]

∅:D[23.25] → [20.452:512]

B:BD[20.452] → [20.452:512]

B:BD[20.512] → [13.688:710]

∅:D[13.710] → [20.534:594]

B:BD[20.534] → [20.534:594]

B:BD[20.594] → [13.711:733]

∅:D[13.733] → [20.616:681]

B:BD[20.616] → [20.616:681]

B:BD[20.681] → [24.1:273]

B:BD[24.284] → [24.284:297]

B:BD[24.297] → [23.26:49]

∅:D[23.49] → [24.405:474]

B:BD[24.405] → [24.405:474]

B:BD[24.474] → [13.734:756]

∅:D[13.756] → [24.496:565]

B:BD[24.496] → [24.496:565]

B:BD[24.565] → [13.757:779]

∅:D[13.779] → [24.587:660]

B:BD[24.587] → [24.587:660]

B:BD[24.660] → [25.1:282]

B:BD[25.293] → [25.293:306]

B:BD[25.306] → [23.50:73]

∅:D[23.73] → [25.414:489]

B:BD[25.414] → [25.414:489]

B:BD[25.489] → [13.780:802]

∅:D[13.802] → [25.511:586]

B:BD[25.511] → [25.511:586]

B:BD[25.586] → [13.803:825]

∅:D[13.825] → [25.608:1048]

B:BD[25.608] → [25.608:1048]

B:BD[25.1059] → [25.1059:1072]

B:BD[25.1072] → [23.74:97]

∅:D[23.97] → [25.1180:1263]

B:BD[25.1180] → [25.1180:1263]

B:BD[25.1263] → [13.826:848]

∅:D[13.848] → [25.1285:1369]

B:BD[25.1285] → [25.1285:1369]

B:BD[25.1369] → [13.849:871]

∅:D[13.871] → [25.1391:1476]

B:BD[25.1391] → [25.1391:1476]

∅:D[25.1476] → [24.660:930]

B:BD[24.660] → [24.660:930]

B:BD[24.941] → [24.941:1127]

B:BD[24.1127] → [23.98:121]

∅:D[23.121] → [24.1235:1304]

B:BD[24.1235] → [24.1235:1304]

B:BD[24.1304] → [13.872:894]

∅:D[13.894] → [24.1326:1395]

B:BD[24.1326] → [24.1326:1395]

B:BD[24.1395] → [13.895:917]

∅:D[13.917] → [24.1417:1487]

B:BD[24.1417] → [24.1417:1487]

B:BD[24.1487] → [26.2:331]

B:BD[26.437] → [26.437:450]

B:BD[26.450] → [23.122:145]

∅:D[23.145] → [26.480:554]

B:BD[26.480] → [26.480:554]

B:BD[26.554] → [13.918:940]

∅:D[13.940] → [26.576:650]

B:BD[26.576] → [26.576:650]

B:BD[26.650] → [13.941:963]

∅:D[13.963] → [26.672:1040]

B:BD[26.672] → [26.672:1040]

B:BD[26.1040] → [23.146:163]

∅:D[23.163] → [26.1064:1127]

B:BD[26.1064] → [26.1064:1127]

B:BD[26.1127] → [13.964:986]

∅:D[13.986] → [26.1149:1213]

B:BD[26.1149] → [26.1149:1213]

B:BD[26.1213] → [13.987:1009]

∅:D[13.1009] → [26.1235:1300]

B:BD[26.1235] → [26.1235:1300]

∅:D[26.1300] → [24.1487:1492]

B:BD[24.1487] → [24.1487:1492]

B:BD[24.1492] → [26.1301:1639]

B:BD[26.1745] → [26.1745:1758]

B:BD[26.1758] → [23.164:187]

∅:D[23.187] → [26.1788:1869]

B:BD[26.1788] → [26.1788:1869]

B:BD[26.1869] → [13.1010:1032]

∅:D[13.1032] → [26.1891:1972]

B:BD[26.1891] → [26.1891:1972]

B:BD[26.1972] → [13.1033:1055]

∅:D[13.1055] → [26.1994:2158]

B:BD[26.1994] → [26.1994:2158]

B:BD[26.2158] → [5.2:34]

∅:D[5.34] → [26.2190:2413]

B:BD[26.2190] → [26.2190:2413]

B:BD[26.2413] → [23.188:205]

∅:D[23.205] → [26.2437:2509]

B:BD[26.2437] → [26.2437:2509]

B:BD[26.2509] → [13.1056:1078]

∅:D[13.1078] → [26.2531:2603]

B:BD[26.2531] → [26.2531:2603]

B:BD[26.2603] → [13.1079:1101]

∅:D[13.1101] → [26.2625:2702]

B:BD[26.2625] → [26.2625:2702]

∅:D[26.2702] → [27.1:281]

B:BD[24.1492] → [27.1:281]

B:BD[27.292] → [27.292:348]

B:BD[27.390] → [27.390:433]

B:BD[27.433] → [28.2:71]

∅:D[28.71] → [27.507:662]

∅:D[23.273] → [27.507:662]

B:BD[27.507] → [27.507:662]

∅:D[27.662] → [21.198:223]

∅:D[24.1492] → [21.198:223]

B:BD[20.681] → [21.198:223]

B:BD[21.223] → [2.33:63]

∅:D[2.63] → [21.248:330]

B:BD[21.248] → [21.248:330]

B:BD[21.330] → [22.298:330]

∅:D[22.330] → [21.349:431]

B:BD[21.349] → [21.349:431]

B:BD[21.537] → [21.537:599]

B:BD[21.599] → [23.274:297]

∅:D[23.297] → [21.629:697]

B:BD[21.629] → [21.629:697]

B:BD[21.697] → [13.1102:1124]

∅:D[13.1124] → [21.719:876]

B:BD[21.719] → [21.719:876]

B:BD[21.876] → [22.331:451]

B:BD[22.451] → [23.298:315]

∅:D[23.315] → [21.900:959]

B:BD[21.900] → [21.900:959]

B:BD[21.959] → [13.1125:1147]

∅:D[13.1147] → [21.981:1045]

B:BD[21.981] → [21.981:1045]

B:BD[21.1045] → [29.1:41]

B:BD[29.41] → [2.64:109]

∅:D[29.81] → [21.1123:1173]

∅:D[2.109] → [21.1123:1173]

B:BD[21.1123] → [21.1123:1173]

B:BD[21.1173] → [30.23:282]

B:BD[30.282] → [29.82:170]

∅:D[29.170] → [21.1423:1537]

B:BD[21.1423] → [21.1423:1537]

B:BD[30.308] → [30.308:538]

∅:D[30.538] → [21.1722:1735]

B:BD[21.1722] → [21.1722:1735]

B:BD[21.1735] → [23.316:339]

∅:D[23.339] → [29.171:254]

B:BD[21.1765] → [29.171:254]

B:BD[29.254] → [22.452:508]

∅:D[22.508] → [30.539:640]

B:BD[21.1902] → [30.539:640]

∅:D[30.640] → [21.1902:1939]

B:BD[21.1902] → [21.1902:1939]

B:BD[21.1939] → [22.509:659]

B:BD[22.659] → [23.340:374]

∅:D[23.374] → [29.300:379]

B:BD[21.1980] → [29.300:379]

B:BD[29.379] → [31.706:1078]

B:BD[31.1184] → [31.1184:1197]

B:BD[31.1197] → [23.375:398]

∅:D[23.398] → [31.1227:1327]

B:BD[31.1227] → [31.1227:1327]

B:BD[31.1327] → [13.1148:1170]

∅:D[13.1170] → [31.1349:1450]

B:BD[31.1349] → [31.1349:1450]

B:BD[31.1450] → [13.1171:1193]

∅:D[13.1193] → [31.1472:2053]

B:BD[31.1472] → [31.1472:2053]

B:BD[31.2053] → [23.399:416]

∅:D[23.416] → [31.2077:2169]

B:BD[31.2077] → [31.2077:2169]

B:BD[31.2169] → [13.1194:1216]

∅:D[13.1216] → [31.2191:2282]

B:BD[31.2191] → [31.2191:2282]

B:BD[31.2282] → [13.1217:1239]

∅:D[13.1239] → [31.2304:2399]

B:BD[31.2304] → [31.2304:2399]

∅:D[31.2399] → [29.379:419]

B:BD[29.379] → [29.379:419]

B:BD[29.419] → [2.110:155]

∅:D[2.155] → [29.459:548]

B:BD[29.459] → [29.459:548]

B:BD[29.548] → [22.660:692]

∅:D[22.692] → [29.567:649]

B:BD[29.567] → [29.567:649]

B:BD[29.755] → [29.755:819]

B:BD[29.819] → [23.417:440]

∅:D[23.440] → [29.849:932]

B:BD[29.849] → [29.849:932]

B:BD[29.932] → [13.1240:1262]

∅:D[13.1262] → [29.954:1037]

B:BD[29.954] → [29.954:1037]

B:BD[29.1037] → [13.1263:1285]

∅:D[13.1285] → [29.1059:1142]

B:BD[29.1059] → [29.1059:1142]

B:BD[29.1142] → [22.693:760]

∅:D[22.760] → [29.1200:1233]

B:BD[29.1200] → [29.1200:1233]

B:BD[29.1233] → [32.1:80]

∅:D[32.80] → [22.838:938]

B:BD[22.838] → [22.838:938]

B:BD[22.938] → [23.441:458]

∅:D[23.458] → [29.1257:1331]

B:BD[29.1257] → [29.1257:1331]

B:BD[29.1331] → [13.1286:1308]

∅:D[13.1308] → [29.1353:1427]

B:BD[29.1353] → [29.1353:1427]

B:BD[29.1427] → [13.1309:1331]

∅:D[13.1331] → [29.1449:1523]

B:BD[29.1449] → [29.1449:1523]

B:BD[29.1635] → [29.1635:1692]

B:BD[29.1692] → [2.156:213]

∅:D[2.213] → [29.1744:1903]

B:BD[29.1744] → [29.1744:1903]

B:BD[29.1903] → [22.939:971]

∅:D[22.971] → [29.1922:2004]

B:BD[29.1922] → [29.1922:2004]

B:BD[29.2110] → [29.2110:2123]

B:BD[29.2123] → [23.459:482]

∅:D[23.482] → [29.2153:2248]

B:BD[29.2153] → [29.2153:2248]

B:BD[29.2248] → [13.1332:1354]

∅:D[13.1354] → [29.2270:2365]

B:BD[29.2270] → [29.2270:2365]

B:BD[29.2365] → [13.1355:1377]

∅:D[13.1377] → [29.2387:2585]

B:BD[29.2387] → [29.2387:2585]

B:BD[29.2585] → [22.972:1146]

B:BD[22.1146] → [23.483:500]

∅:D[23.500] → [29.2609:2695]

B:BD[29.2609] → [29.2609:2695]

B:BD[29.2695] → [13.1378:1400]

∅:D[13.1400] → [29.2717:2803]

B:BD[29.2717] → [29.2717:2803]

B:BD[29.2803] → [13.1401:1423]

∅:D[13.1423] → [29.2825:2911]

B:BD[29.2825] → [29.2825:2911]

B:BD[29.2911] → [22.1147:1211]

B:BD[22.1211] → [2.214:278]

∅:D[2.278] → [22.1270:1549]

B:BD[22.1270] → [22.1270:1549]

B:BD[22.1655] → [22.1655:1668]

B:BD[22.1668] → [23.501:524]

∅:D[23.524] → [22.1698:1800]

B:BD[22.1698] → [22.1698:1800]

B:BD[22.1800] → [13.1424:1446]

∅:D[13.1446] → [22.1822:1924]

B:BD[22.1822] → [22.1822:1924]

B:BD[22.1924] → [13.1447:1469]

∅:D[13.1469] → [22.1946:2485]

B:BD[22.1946] → [22.1946:2485]

B:BD[22.2485] → [23.525:542]

∅:D[23.542] → [22.2509:2602]

B:BD[22.2509] → [22.2509:2602]

B:BD[22.2602] → [13.1470:1492]

∅:D[13.1492] → [22.2624:2718]

B:BD[22.2624] → [22.2624:2718]

B:BD[22.2718] → [13.1493:1515]

∅:D[13.1515] → [22.2750:2935]

B:BD[22.2750] → [22.2750:2935]

B:BD[22.2935] → [2.279:371]

∅:D[2.371] → [22.3022:3300]

B:BD[22.3022] → [22.3022:3300]

B:BD[22.3406] → [22.3406:3419]

B:BD[22.3419] → [23.543:566]

∅:D[23.566] → [22.3449:3579]

B:BD[22.3449] → [22.3449:3579]

B:BD[22.3579] → [13.1516:1538]

∅:D[13.1538] → [22.3601:3731]

B:BD[22.3601] → [22.3601:3731]

B:BD[22.3731] → [13.1539:1561]

∅:D[13.1561] → [22.3753:4358]

B:BD[22.3753] → [22.3753:4358]

B:BD[22.4358] → [23.567:584]

∅:D[23.584] → [22.4382:4503]

B:BD[22.4382] → [22.4382:4503]

B:BD[22.4503] → [13.1562:1584]

∅:D[13.1584] → [22.4525:4648]

B:BD[22.4525] → [22.4525:4648]

B:BD[22.4648] → [13.1585:1607]

∅:D[13.1607] → [22.4670:4789]

B:BD[22.4670] → [22.4670:4789]

B:BD[22.4789] → [33.1:369]

B:BD[33.475] → [33.475:488]

B:BD[33.488] → [23.585:608]

∅:D[23.608] → [33.518:636]

B:BD[33.518] → [33.518:636]

B:BD[33.636] → [13.1608:1630]

∅:D[13.1630] → [33.658:776]

B:BD[33.658] → [33.658:776]

B:BD[33.776] → [13.1631:1653]

∅:D[13.1653] → [33.798:1864]

B:BD[33.798] → [33.798:1864]

B:BD[33.1864] → [23.609:626]

∅:D[23.626] → [33.1888:1999]

B:BD[33.1888] → [33.1888:1999]

B:BD[33.1999] → [13.1654:1676]

∅:D[13.1676] → [33.2021:2128]

B:BD[33.2021] → [33.2021:2128]

B:BD[33.2128] → [13.1677:1699]

∅:D[13.1699] → [33.2150:2259]

B:BD[33.2150] → [33.2150:2259]

∅:D[33.2259] → [34.279:322]

∅:D[22.4789] → [34.279:322]

B:BD[34.279] → [34.279:322]

B:BD[34.322] → [2.372:415]

∅:D[2.415] → [34.360:616]

B:BD[34.360] → [34.360:616]

B:BD[34.722] → [34.722:735]

B:BD[34.735] → [23.627:650]

∅:D[23.650] → [34.765:846]

B:BD[34.765] → [34.765:846]

B:BD[34.846] → [13.1700:1722]

∅:D[13.1722] → [34.868:949]

B:BD[34.868] → [34.868:949]

B:BD[34.949] → [13.1723:1745]

∅:D[13.1745] → [34.971:1052]

B:BD[34.971] → [34.971:1052]

B:BD[34.1052] → [22.4790:4852]

∅:D[22.4852] → [34.1108:1139]

B:BD[34.1108] → [34.1108:1139]

B:BD[34.1139] → [22.4853:5028]

B:BD[22.5028] → [23.651:668]

∅:D[23.668] → [34.1163:1235]

B:BD[34.1163] → [34.1163:1235]

B:BD[34.1235] → [13.1746:1768]

∅:D[13.1768] → [34.1257:1329]

B:BD[34.1257] → [34.1257:1329]

B:BD[34.1329] → [13.1769:1791]

∅:D[13.1791] → [34.1351:1423]

B:BD[34.1351] → [34.1351:1423]

B:BD[34.1608] → [34.1608:1661]

B:BD[34.1661] → [2.416:469]

∅:D[2.469] → [34.1709:1954]

B:BD[34.1709] → [34.1709:1954]

B:BD[34.2060] → [34.2060:2073]

B:BD[34.2073] → [23.669:692]

∅:D[23.692] → [34.2103:2194]

B:BD[34.2103] → [34.2103:2194]

B:BD[34.2194] → [13.1792:1814]

∅:D[13.1814] → [34.2216:2307]

B:BD[34.2216] → [34.2216:2307]

B:BD[34.2307] → [13.1815:1837]

∅:D[13.1837] → [34.2329:2517]

B:BD[34.2329] → [34.2329:2517]

B:BD[34.2517] → [22.5029:5195]

B:BD[22.5195] → [23.693:710]

∅:D[23.710] → [34.2541:2623]

B:BD[34.2541] → [34.2541:2623]

B:BD[34.2623] → [13.1838:1860]

∅:D[13.1860] → [34.2645:2727]

B:BD[34.2645] → [34.2645:2727]

B:BD[34.2727] → [13.1861:1883]

∅:D[13.1883] → [34.2749:2831]

B:BD[34.2749] → [34.2749:2831]

B:BD[34.2831] → [22.5196:5256]

B:BD[22.5256] → [2.470:530]

∅:D[2.530] → [35.1:63]

B:BD[22.5311] → [35.1:63]

∅:D[35.63] → [36.552:647]

B:BD[36.552] → [36.552:647]

∅:D[36.647] → [22.5455:5487]

B:BD[22.5455] → [22.5455:5487]

B:BD[22.5487] → [36.648:708]

∅:D[36.708] → [22.5547:5569]

B:BD[22.5547] → [22.5547:5569]

B:BD[22.5675] → [22.5675:5688]

B:BD[22.5688] → [23.711:734]

∅:D[23.734] → [36.709:807]

B:BD[22.5718] → [36.709:807]

B:BD[36.807] → [13.1884:1906]

∅:D[13.1906] → [36.808:906]

B:BD[22.5958] → [36.808:906]

B:BD[36.906] → [35.64:139]

∅:D[35.139] → [22.6122:6153]

B:BD[22.6122] → [22.6122:6153]

B:BD[22.6153] → [23.735:752]

∅:D[23.752] → [36.907:997]

B:BD[22.6177] → [36.907:997]

B:BD[36.997] → [13.1907:1929]

∅:D[13.1929] → [36.998:1087]

B:BD[22.6288] → [36.998:1087]

B:BD[36.1087] → [13.1930:1952]

∅:D[13.1952] → [36.1088:1364]

B:BD[22.6399] → [36.1088:1364]

B:BD[36.1364] → [3.1:181]

∅:D[3.181] → [21.2148:2153]

∅:D[36.1535] → [21.2148:2153]

∅:D[29.2911] → [21.2148:2153]

∅:D[34.2997] → [21.2148:2153]

∅:D[22.6668] → [21.2148:2153]

B:BD[21.2148] → [21.2148:2153]

B:BD[21.2153] → [35.140:197]

B:BD[35.197] → [2.531:593]

∅:D[2.593] → [35.254:514]

B:BD[35.254] → [35.254:514]

B:BD[35.620] → [35.620:633]

B:BD[35.633] → [23.753:776]

∅:D[23.776] → [35.663:763]

B:BD[35.663] → [35.663:763]

B:BD[35.763] → [13.1953:1975]

∅:D[13.1975] → [35.785:885]

B:BD[35.785] → [35.785:885]

B:BD[35.885] → [13.1976:1998]

∅:D[13.1998] → [35.907:1130]

B:BD[35.907] → [35.907:1130]

B:BD[35.1130] → [23.777:794]

∅:D[23.794] → [35.1154:1245]

B:BD[35.1154] → [35.1154:1245]

B:BD[35.1245] → [13.1999:2021]

∅:D[13.2021] → [35.1267:1358]

B:BD[35.1267] → [35.1267:1358]

B:BD[35.1358] → [13.2022:2044]

∅:D[13.2044] → [35.1380:1662]

B:BD[35.1380] → [35.1380:1662]

B:BD[35.1662] → [3.182:366]

∅:D[3.366] → [35.1837:1842]

B:BD[35.1837] → [35.1837:1842]

B:BD[35.1842] → [32.81:131]

B:BD[32.131] → [37.1:56]

∅:D[37.56] → [32.188:467]

B:BD[32.188] → [32.188:467]

B:BD[32.573] → [32.573:586]

B:BD[32.586] → [23.795:818]

∅:D[23.818] → [37.57:150]

B:BD[32.616] → [37.57:150]

B:BD[37.150] → [13.2045:2067]

∅:D[13.2067] → [37.151:244]

B:BD[32.733] → [37.151:244]

B:BD[37.244] → [13.2068:2090]

∅:D[13.2090] → [37.245:338]

B:BD[32.850] → [37.245:338]

∅:D[37.338] → [32.945:1042]

B:BD[32.945] → [32.945:1042]

B:BD[32.1042] → [37.339:509]

B:BD[37.509] → [23.819:836]

∅:D[23.836] → [32.1240:1262]

B:BD[32.1240] → [32.1240:1262]

B:BD[32.1262] → [13.2091:2113]

∅:D[13.2113] → [37.510:594]

B:BD[32.1284] → [37.510:594]

B:BD[37.594] → [13.2114:2136]

∅:D[13.2136] → [37.595:679]

B:BD[32.1392] → [37.595:679]

∅:D[37.679] → [32.1478:1483]

B:BD[32.1478] → [32.1478:1483]

∅:D[32.1483] → [38.1:248]

B:BD[35.1842] → [38.1:248]

B:BD[38.354] → [38.354:415]

B:BD[38.415] → [23.837:860]

∅:D[23.860] → [38.445:511]

B:BD[38.445] → [38.445:511]

B:BD[38.511] → [13.2137:2159]

∅:D[13.2159] → [38.533:798]

B:BD[38.533] → [38.533:798]

B:BD[38.798] → [23.861:878]

∅:D[23.878] → [38.822:879]

B:BD[38.822] → [38.822:879]

B:BD[38.879] → [13.2160:2182]

∅:D[13.2182] → [38.901:1345]

B:BD[38.901] → [38.901:1345]

B:BD[38.1451] → [38.1451:1464]

B:BD[38.1464] → [23.879:902]

∅:D[23.902] → [38.1494:1586]

B:BD[38.1494] → [38.1494:1586]

B:BD[38.1586] → [13.2183:2205]

∅:D[13.2205] → [38.1608:1700]

B:BD[38.1608] → [38.1608:1700]

B:BD[38.1700] → [13.2206:2228]

∅:D[13.2228] → [38.1722:2216]

B:BD[38.1722] → [38.1722:2216]

B:BD[38.2216] → [23.903:920]

∅:D[23.920] → [38.2240:2324]

B:BD[38.2240] → [38.2240:2324]

B:BD[38.2324] → [13.2229:2251]

∅:D[13.2251] → [38.2346:2429]

B:BD[38.2346] → [38.2346:2429]

B:BD[38.2429] → [13.2252:2274]

∅:D[13.2274] → [38.2451:2944]

B:BD[38.2451] → [38.2451:2944]

B:BD[38.3050] → [38.3050:3063]

B:BD[38.3063] → [23.921:944]

∅:D[23.944] → [38.3093:3194]

B:BD[38.3093] → [38.3093:3194]

B:BD[38.3194] → [13.2275:2297]

∅:D[13.2297] → [38.3216:3746]

B:BD[38.3216] → [38.3216:3746]

B:BD[38.3746] → [23.945:962]

∅:D[23.962] → [38.3770:3863]

B:BD[38.3770] → [38.3770:3863]

B:BD[38.3863] → [13.2298:2320]

∅:D[13.2320] → [38.3885:3977]

B:BD[38.3885] → [38.3885:3977]

B:BD[38.3977] → [13.2321:2343]

∅:D[13.2343] → [38.3999:4092]

B:BD[38.3999] → [38.3999:4092]

B:BD[38.4092] → [39.1:368]

B:BD[39.474] → [39.474:487]

B:BD[39.487] → [23.963:986]

∅:D[23.986] → [39.517:610]

B:BD[39.517] → [39.517:610]

B:BD[39.610] → [13.2344:2366]

∅:D[13.2366] → [39.632:725]

B:BD[39.632] → [39.632:725]

B:BD[39.725] → [13.2367:2389]

∅:D[13.2389] → [39.747:1191]

B:BD[39.747] → [39.747:1191]

B:BD[39.1191] → [23.987:1004]

∅:D[23.1004] → [39.1215:1299]

B:BD[39.1215] → [39.1215:1299]

B:BD[39.1299] → [13.2390:2412]

∅:D[13.2412] → [39.1321:1403]

B:BD[39.1321] → [39.1321:1403]

B:BD[39.1403] → [13.2413:2435]

∅:D[13.2435] → [39.1425:1508]

B:BD[39.1425] → [39.1425:1508]

∅:D[39.1508] → [38.4092:4097]

B:BD[38.4092] → [38.4092:4097]

B:BD[38.4097] → [40.1:409]

B:BD[40.515] → [40.515:528]

B:BD[40.528] → [23.1005:1028]

∅:D[23.1028] → [40.558:1118]

B:BD[40.558] → [40.558:1118]

B:BD[40.1118] → [23.1029:1046]

∅:D[23.1046] → [40.1142:1251]

B:BD[40.1142] → [40.1142:1251]

B:BD[40.1251] → [13.2436:2458]

∅:D[13.2458] → [40.1273:1388]

B:BD[40.1273] → [40.1273:1388]

∅:D[40.1388] → [41.1:381]

B:BD[38.4097] → [41.1:381]

B:BD[41.392] → [41.392:405]

B:BD[41.405] → [23.1047:1070]

∅:D[23.1070] → [41.513:711]

B:BD[41.513] → [41.513:711]

B:BD[41.711] → [13.2459:2481]

∅:D[13.2481] → [41.733:851]

B:BD[41.733] → [41.733:851]

B:BD[41.851] → [13.2482:2504]

∅:D[13.2504] → [41.873:1211]

B:BD[41.873] → [41.873:1211]

B:BD[41.1211] → [23.1071:1088]

∅:D[23.1088] → [41.1235:1353]

B:BD[41.1235] → [41.1235:1353]

B:BD[41.1353] → [13.2505:2527]

∅:D[13.2527] → [41.1375:1493]

B:BD[41.1375] → [41.1375:1493]

B:BD[41.1493] → [13.2528:2550]

∅:D[13.2550] → [41.1515:1707]

B:BD[41.1515] → [41.1515:1707]

B:BD[41.1749] → [41.1749:1792]

B:BD[41.1792] → [28.72:155]

∅:D[28.155] → [41.1871:2046]

∅:D[23.1170] → [41.1871:2046]

B:BD[41.1871] → [41.1871:2046]

B:BD[41.2046] → [42.1:336]

B:BD[42.442] → [42.442:455]

B:BD[42.455] → [23.1171:1194]

∅:D[23.1194] → [42.485:568]

B:BD[42.485] → [42.485:568]

B:BD[42.568] → [13.2551:2573]

∅:D[13.2573] → [42.590:673]

B:BD[42.590] → [42.590:673]

B:BD[42.673] → [13.2574:2596]

∅:D[13.2596] → [42.695:1029]

B:BD[42.695] → [42.695:1029]

B:BD[42.1029] → [23.1195:1212]

∅:D[23.1212] → [42.1053:1130]

B:BD[42.1053] → [42.1053:1130]

B:BD[42.1130] → [13.2597:2619]

∅:D[13.2619] → [42.1152:1226]

B:BD[42.1152] → [42.1152:1226]

B:BD[42.1226] → [13.2620:2642]

∅:D[13.2642] → [42.1248:1707]

B:BD[42.1248] → [42.1248:1707]

B:BD[42.1813] → [42.1813:1826]

B:BD[42.1826] → [23.1213:1236]

∅:D[23.1236] → [42.1856:1951]

B:BD[42.1856] → [42.1856:1951]

B:BD[42.1951] → [13.2643:2665]

∅:D[13.2665] → [42.1973:2176]

B:BD[42.1973] → [42.1973:2176]

B:BD[42.2176] → [23.1237:1254]

∅:D[23.1254] → [42.2200:2288]

B:BD[42.2200] → [42.2200:2288]

B:BD[42.2288] → [13.2666:2688]

∅:D[13.2688] → [42.2310:2394]

B:BD[42.2310] → [42.2310:2394]

B:BD[42.2394] → [13.2689:2711]

∅:D[13.2711] → [42.2416:2857]

B:BD[42.2416] → [42.2416:2857]

B:BD[42.2857] → [15.3720:4223]

B:BD[15.4234] → [15.4234:4725]

∅:D[42.2857] → [41.2046:2051]

∅:D[15.4725] → [41.2046:2051]

B:BD[41.2046] → [41.2046:2051]

B:BD[41.2051] → [15.4726:4775]

B:BD[15.4775] → [4.1:55]

∅:D[4.55] → [15.4821:5083]

B:BD[15.4821] → [15.4821:5083]

B:BD[15.5094] → [15.5094:5629]

B:BD[15.5629] → [4.56:107]

∅:D[4.107] → [15.5675:5937]

B:BD[15.5675] → [15.5675:5937]

B:BD[15.5948] → [15.5948:6598]

B:BD[15.6598] → [4.108:154]

∅:D[4.154] → [15.6644:6879]

B:BD[15.6644] → [15.6644:6879]

B:BD[15.6890] → [15.6890:7504]

B:BD[15.7504] → [4.155:203]

∅:D[4.203] → [15.7550:7787]

B:BD[15.7550] → [15.7550:7787]

B:BD[15.7798] → [15.7798:8374]

B:BD[15.8374] → [10.2791:3058]

B:BD[10.3069] → [10.3069:3440]

B:BD[10.3440] → [23.1255:1278]

∅:D[23.1278] → [10.3548:3624]

B:BD[10.3548] → [10.3548:3624]

B:BD[10.3624] → [13.2712:2734]

∅:D[13.2734] → [10.3646:3723]

B:BD[10.3646] → [10.3646:3723]

B:BD[10.3723] → [13.2735:2757]

∅:D[13.2757] → [10.3745:3831]

B:BD[10.3745] → [10.3745:3831]

B:BD[10.3831] → [43.2:34]

∅:D[43.34] → [10.3863:4143]

B:BD[10.3863] → [10.3863:4143]

B:BD[10.4143] → [23.1279:1296]

∅:D[23.1296] → [10.4167:4234]

B:BD[10.4167] → [10.4167:4234]

B:BD[10.4234] → [13.2758:2780]

∅:D[13.2780] → [10.4256:4323]

B:BD[10.4256] → [10.4256:4323]

B:BD[10.4323] → [13.2781:2803]

∅:D[13.2803] → [10.4345:4685]

B:BD[10.4345] → [10.4345:4685]

B:BD[10.4696] → [10.4696:5074]

B:BD[10.5074] → [23.1297:1320]

∅:D[23.1320] → [10.5182:5258]

B:BD[10.5182] → [10.5182:5258]

B:BD[10.5258] → [13.2804:2826]

∅:D[13.2826] → [10.5280:5356]

B:BD[10.5280] → [10.5280:5356]

B:BD[10.5356] → [13.2827:2849]

∅:D[13.2849] → [10.5378:5516]

B:BD[10.5378] → [10.5378:5516]

B:BD[10.5516] → [43.35:67]

∅:D[43.67] → [10.5548:5984]

B:BD[10.5548] → [10.5548:5984]

B:BD[10.5984] → [23.1321:1338]

∅:D[23.1338] → [10.6008:6075]

B:BD[10.6008] → [10.6008:6075]

B:BD[10.6075] → [13.2850:2872]

∅:D[13.2872] → [10.6097:6165]

B:BD[10.6097] → [10.6097:6165]

B:BD[10.6165] → [13.2873:2895]

∅:D[13.2895] → [10.6187:6254]

B:BD[10.6187] → [10.6187:6254]

∅:D[44.614] → [10.6254:6259]

B:BD[10.6254] → [10.6254:6259]

function test_draw_text()
  io.write('\ntest_draw_text')
  App.screen.init{width=120, height=60}
  Lines = load_array{'abc', 'def', 'ghi'}
  Line_width = App.screen.width
  Cursor1 = {line=1, pos=1}
  Screen_top1 = {line=1, pos=1}
  Screen_bottom1 = {}
  App.draw()
  local y = Margin_top
  App.screen.check(y, 'abc', 'F - test_draw_text/screen:1')
  y = y + Line_height
  App.screen.check(y, 'def', 'F - test_draw_text/screen:2')
  y = y + Line_height
  App.screen.check(y, 'ghi', 'F - test_draw_text/screen:3')
end
function test_draw_wrapping_text()
  io.write('\ntest_draw_wrapping_text')
  App.screen.init{width=50, height=60}
  Lines = load_array{'abc', 'defgh', 'xyz'}
  Line_width = App.screen.width
  Cursor1 = {line=1, pos=1}
  Screen_top1 = {line=1, pos=1}
  Screen_bottom1 = {}
  App.draw()
  local y = Margin_top
  App.screen.check(y, 'abc', 'F - test_draw_wrapping_text/screen:1')
  y = y + Line_height
  App.screen.check(y, 'def', 'F - test_draw_wrapping_text/screen:2')
  y = y + Line_height
  App.screen.check(y, 'gh', 'F - test_draw_wrapping_text/screen:3')
end
function test_draw_word_wrapping_text()
  io.write('\ntest_draw_word_wrapping_text')
  App.screen.init{width=60, height=60}
  Lines = load_array{'abc def ghi', 'jkl'}
  Line_width = App.screen.width
  Cursor1 = {line=1, pos=1}
  Screen_top1 = {line=1, pos=1}
  Screen_bottom1 = {}
  App.draw()
  local y = Margin_top
  App.screen.check(y, 'abc ', 'F - test_draw_word_wrapping_text/screen:1')
  y = y + Line_height
  App.screen.check(y, 'def ', 'F - test_draw_word_wrapping_text/screen:2')
  y = y + Line_height
  App.screen.check(y, 'ghi', 'F - test_draw_word_wrapping_text/screen:3')
end
function test_draw_text_wrapping_within_word()
  -- arrange a screen line that needs to be split within a word
  io.write('\ntest_draw_text_wrapping_within_word')
  App.screen.init{width=60, height=60}
  Lines = load_array{'abcd e fghijk', 'xyz'}
  Line_width = App.screen.width
  Cursor1 = {line=1, pos=1}
  Screen_top1 = {line=1, pos=1}
  Screen_bottom1 = {}
  App.draw()
  local y = Margin_top
  App.screen.check(y, 'abcd ', 'F - test_draw_text_wrapping_within_word/screen:1')
  y = y + Line_height
  App.screen.check(y, 'e fghi', 'F - test_draw_text_wrapping_within_word/screen:2')
  y = y + Line_height
  App.screen.check(y, 'jk', 'F - test_draw_text_wrapping_within_word/screen:3')
end
function test_edit_wrapping_text()
  io.write('\ntest_edit_wrapping_text')
  App.screen.init{width=50, height=60}
  Lines = load_array{'abc', 'def', 'xyz'}
  Line_width = App.screen.width
  Cursor1 = {line=2, pos=4}
  Screen_top1 = {line=1, pos=1}
  Screen_bottom1 = {}
  App.run_after_textinput('g')
  App.run_after_textinput('h')
  App.run_after_textinput('i')
  App.run_after_textinput('j')
  App.run_after_textinput('k')
  App.run_after_textinput('l')
  local y = Margin_top
  App.screen.check(y, 'abc', 'F - test_edit_wrapping_text/screen:1')
  y = y + Line_height
  App.screen.check(y, 'def', 'F - test_edit_wrapping_text/screen:2')
  y = y + Line_height
  App.screen.check(y, 'ghij', 'F - test_edit_wrapping_text/screen:3')
end
function test_insert_newline()
  io.write('\ntest_insert_newline')
  -- display a few lines with cursor on bottom line
  App.screen.init{width=25+30, height=60}
  Lines = load_array{'abc', 'def', 'ghi', 'jkl'}
  Line_width = App.screen.width
  Cursor1 = {line=1, pos=2}
  Screen_top1 = {line=1, pos=1}
  Screen_bottom1 = {}
  App.draw()
  local y = Margin_top
  App.screen.check(y, 'abc', 'F - test_insert_newline/baseline/screen:1')
  y = y + Line_height
  App.screen.check(y, 'def', 'F - test_insert_newline/baseline/screen:2')
  y = y + Line_height
  App.screen.check(y, 'ghi', 'F - test_insert_newline/baseline/screen:3')
  -- after hitting the enter key the screen scrolls down
  App.run_after_keychord('return')
  check_eq(Screen_top1.line, 1, 'F - test_insert_newline/screen_top')
  check_eq(Cursor1.line, 2, 'F - test_insert_newline/cursor:line')
  check_eq(Cursor1.pos, 1, 'F - test_insert_newline/cursor:pos')
  y = Margin_top
  App.screen.check(y, 'a', 'F - test_insert_newline/screen:1')
  y = y + Line_height
  App.screen.check(y, 'bc', 'F - test_insert_newline/screen:2')
  y = y + Line_height
  App.screen.check(y, 'def', 'F - test_insert_newline/screen:3')
end
function test_insert_from_clipboard()
  io.write('\ntest_insert_from_clipboard')
  -- display a few lines with cursor on bottom line
  App.screen.init{width=25+30, height=60}
  Lines = load_array{'abc', 'def', 'ghi', 'jkl'}
  Line_width = App.screen.width
  Cursor1 = {line=1, pos=2}
  Screen_top1 = {line=1, pos=1}
  Screen_bottom1 = {}
  App.draw()
  local y = Margin_top
  App.screen.check(y, 'abc', 'F - test_insert_from_clipboard/baseline/screen:1')
  y = y + Line_height
  App.screen.check(y, 'def', 'F - test_insert_from_clipboard/baseline/screen:2')
  y = y + Line_height
  App.screen.check(y, 'ghi', 'F - test_insert_from_clipboard/baseline/screen:3')
  -- after hitting the enter key the screen scrolls down
  App.clipboard = 'xy\nz'
  App.run_after_keychord('C-v')
  check_eq(Screen_top1.line, 1, 'F - test_insert_from_clipboard/screen_top')
  check_eq(Cursor1.line, 2, 'F - test_insert_from_clipboard/cursor:line')
  check_eq(Cursor1.pos, 2, 'F - test_insert_from_clipboard/cursor:pos')
  y = Margin_top
  App.screen.check(y, 'axy', 'F - test_insert_from_clipboard/screen:1')
  y = y + Line_height
  App.screen.check(y, 'zbc', 'F - test_insert_from_clipboard/screen:2')
  y = y + Line_height
  App.screen.check(y, 'def', 'F - test_insert_from_clipboard/screen:3')
end
function test_move_cursor_using_mouse()
  io.write('\ntest_move_cursor_using_mouse')
  App.screen.init{width=50, height=60}
  Lines = load_array{'abc', 'def', 'xyz'}
  Line_width = App.screen.width
  Cursor1 = {line=1, pos=1}
  Screen_top1 = {line=1, pos=1}
  Screen_bottom1 = {}
  App.draw()  -- populate line.y for each line in Lines
  local screen_left_margin = 25  -- pixels
  App.run_after_mouserelease(screen_left_margin+8,Margin_top+5, '1')
  check_eq(Cursor1.line, 1, 'F - test_move_cursor_using_mouse/cursor:line')
  check_eq(Cursor1.pos, 2, 'F - test_move_cursor_using_mouse/cursor:pos')
end
function test_pagedown()
  io.write('\ntest_pagedown')
  App.screen.init{width=120, height=45}
  Lines = load_array{'abc', 'def', 'ghi'}
  Line_width = App.screen.width
  Cursor1 = {line=1, pos=1}
  Screen_top1 = {line=1, pos=1}
  Screen_bottom1 = {}
  -- initially the first two lines are displayed
  App.draw()
  local y = Margin_top
  App.screen.check(y, 'abc', 'F - test_pagedown/baseline/screen:1')
  y = y + Line_height
  App.screen.check(y, 'def', 'F - test_pagedown/baseline/screen:2')
  -- after pagedown the bottom line becomes the top
  App.run_after_keychord('pagedown')
  check_eq(Screen_top1.line, 2, 'F - test_pagedown/screen_top')
  check_eq(Cursor1.line, 2, 'F - test_pagedown/cursor')
  y = Margin_top
  App.screen.check(y, 'def', 'F - test_pagedown/screen:1')
  y = y + Line_height
  App.screen.check(y, 'ghi', 'F - test_pagedown/screen:2')
end
function test_pagedown_skips_drawings()
  io.write('\ntest_pagedown_skips_drawings')
  -- some lines of text with a drawing intermixed
  App.screen.init{width=50, height=80}
  Lines = load_array{'abc',               -- height 15
                     '```lines', '```',   -- height 25
                     'def',               -- height 15
                     'ghi'}               -- height 15
  check_eq(Lines[2].mode, 'drawing', 'F - test_pagedown_skips_drawings/baseline/lines')
  Line_width = App.screen.width
  Cursor1 = {line=1, pos=1}
  Screen_top1 = {line=1, pos=1}
  Screen_bottom1 = {}
  local drawing_height = 20 + App.screen.width / 2  -- default
  -- initially the screen displays the first line and the drawing
  -- 15px margin + 15px line1 + 10px margin + 25px drawing + 10px margin = 75px < screen height 80px
  App.draw()
  local y = Margin_top
  App.screen.check(y, 'abc', 'F - test_pagedown_skips_drawings/baseline/screen:1')
  -- after pagedown the screen draws the drawing up top
  -- 15px margin + 10px margin + 25px drawing + 10px margin + 15px line3 = 75px < screen height 80px
  App.run_after_keychord('pagedown')
  check_eq(Screen_top1.line, 2, 'F - test_pagedown_skips_drawings/screen_top')
  check_eq(Cursor1.line, 3, 'F - test_pagedown_skips_drawings/cursor')
  y = Margin_top + drawing_height
  App.screen.check(y, 'def', 'F - test_pagedown_skips_drawings/screen:1')
end
function test_pagedown_shows_one_screen_line_in_common()
  io.write('\ntest_pagedown_shows_one_screen_line_in_common')
  -- some lines of text with a drawing intermixed
  App.screen.init{width=50, height=60}
  Lines = load_array{'abc', 'def ghi jkl', 'mno'}
  Line_width = App.screen.width
  Cursor1 = {line=1, pos=1}
  Screen_top1 = {line=1, pos=1}
  Screen_bottom1 = {}
  App.draw()
  local y = Margin_top
  App.screen.check(y, 'abc', 'F - test_pagedown_shows_one_screen_line_in_common/baseline/screen:1')
  y = y + Line_height
  App.screen.check(y, 'def ', 'F - test_pagedown_shows_one_screen_line_in_common/baseline/screen:2')
  y = y + Line_height
  App.screen.check(y, 'ghi ', 'F - test_pagedown_shows_one_screen_line_in_common/baseline/screen:3')
  -- after pagedown the bottom screen line becomes the top
  App.run_after_keychord('pagedown')
  check_eq(Screen_top1.line, 2, 'F - test_pagedown_shows_one_screen_line_in_common/screen_top:line')
  check_eq(Screen_top1.pos, 5, 'F - test_pagedown_shows_one_screen_line_in_common/screen_top:pos')
  check_eq(Cursor1.line, 2, 'F - test_pagedown_shows_one_screen_line_in_common/cursor:line')
  check_eq(Cursor1.pos, 5, 'F - test_pagedown_shows_one_screen_line_in_common/cursor:pos')
  y = Margin_top
  App.screen.check(y, 'ghi ', 'F - test_pagedown_shows_one_screen_line_in_common/screen:1')
  y = y + Line_height
  App.screen.check(y, 'jkl', 'F - test_pagedown_shows_one_screen_line_in_common/screen:2')
  y = y + Line_height
  App.screen.check(y, 'mn', 'F - test_pagedown_shows_one_screen_line_in_common/screen:3')
end
function test_down_arrow_moves_cursor()
  io.write('\ntest_down_arrow_moves_cursor')
  App.screen.init{width=120, height=60}
  Lines = load_array{'abc', 'def', 'ghi', 'jkl'}
  Line_width = App.screen.width
  Cursor1 = {line=1, pos=1}
  Screen_top1 = {line=1, pos=1}
  Screen_bottom1 = {}
  -- initially the first three lines are displayed
  App.draw()
  local y = Margin_top
  App.screen.check(y, 'abc', 'F - test_down_arrow_moves_cursor/baseline/screen:1')
  y = y + Line_height
  App.screen.check(y, 'def', 'F - test_down_arrow_moves_cursor/baseline/screen:2')
  y = y + Line_height
  App.screen.check(y, 'ghi', 'F - test_down_arrow_moves_cursor/baseline/screen:3')
  -- after hitting the down arrow, the cursor moves down by 1 line
  App.run_after_keychord('down')
  check_eq(Screen_top1.line, 1, 'F - test_down_arrow_moves_cursor/screen_top')
  check_eq(Cursor1.line, 2, 'F - test_down_arrow_moves_cursor/cursor')
  -- the screen is unchanged
  y = Margin_top
  App.screen.check(y, 'abc', 'F - test_down_arrow_moves_cursor/screen:1')
  y = y + Line_height
  App.screen.check(y, 'def', 'F - test_down_arrow_moves_cursor/screen:2')
  y = y + Line_height
  App.screen.check(y, 'ghi', 'F - test_down_arrow_moves_cursor/screen:3')
end
function test_down_arrow_scrolls_down_by_one_line()
  io.write('\ntest_down_arrow_scrolls_down_by_one_line')
  -- display the first three lines with the cursor on the bottom line
  App.screen.init{width=120, height=60}
  Lines = load_array{'abc', 'def', 'ghi', 'jkl'}
  Line_width = App.screen.width
  Cursor1 = {line=3, pos=1}
  Screen_top1 = {line=1, pos=1}
  Screen_bottom1 = {}
  App.draw()
  local y = Margin_top
  App.screen.check(y, 'abc', 'F - test_down_arrow_scrolls_down_by_one_line/baseline/screen:1')
  y = y + Line_height
  App.screen.check(y, 'def', 'F - test_down_arrow_scrolls_down_by_one_line/baseline/screen:2')
  y = y + Line_height
  App.screen.check(y, 'ghi', 'F - test_down_arrow_scrolls_down_by_one_line/baseline/screen:3')
  -- after hitting the down arrow the screen scrolls down by one line
  App.run_after_keychord('down')
  check_eq(Screen_top1.line, 2, 'F - test_down_arrow_scrolls_down_by_one_line/screen_top')
  check_eq(Cursor1.line, 4, 'F - test_down_arrow_scrolls_down_by_one_line/cursor')
  y = Margin_top
  App.screen.check(y, 'def', 'F - test_down_arrow_scrolls_down_by_one_line/screen:1')
  y = y + Line_height
  App.screen.check(y, 'ghi', 'F - test_down_arrow_scrolls_down_by_one_line/screen:2')
  y = y + Line_height
  App.screen.check(y, 'jkl', 'F - test_down_arrow_scrolls_down_by_one_line/screen:3')
end
function test_down_arrow_scrolls_down_by_one_screen_line()
  io.write('\ntest_down_arrow_scrolls_down_by_one_screen_line')
  -- display the first three lines with the cursor on the bottom line
  App.screen.init{width=25+30, height=60}
  Lines = load_array{'abc', 'def', 'ghi jkl', 'mno'}
  Line_width = App.screen.width
  Cursor1 = {line=3, pos=1}
  Screen_top1 = {line=1, pos=1}
  Screen_bottom1 = {}
  App.draw()
  local y = Margin_top
  App.screen.check(y, 'abc', 'F - test_down_arrow_scrolls_down_by_one_screen_line/baseline/screen:1')
  y = y + Line_height
  App.screen.check(y, 'def', 'F - test_down_arrow_scrolls_down_by_one_screen_line/baseline/screen:2')
  y = y + Line_height
  App.screen.check(y, 'ghi ', 'F - test_down_arrow_scrolls_down_by_one_screen_line/baseline/screen:3')  -- line wrapping includes trailing whitespace
  -- after hitting the down arrow the screen scrolls down by one line
  App.run_after_keychord('down')
  check_eq(Screen_top1.line, 2, 'F - test_down_arrow_scrolls_down_by_one_screen_line/screen_top')
  check_eq(Cursor1.line, 3, 'F - test_down_arrow_scrolls_down_by_one_screen_line/cursor:line')
  check_eq(Cursor1.pos, 5, 'F - test_down_arrow_scrolls_down_by_one_screen_line/cursor:pos')
  y = Margin_top
  App.screen.check(y, 'def', 'F - test_down_arrow_scrolls_down_by_one_screen_line/screen:1')
  y = y + Line_height
  App.screen.check(y, 'ghi ', 'F - test_down_arrow_scrolls_down_by_one_screen_line/screen:2')
  y = y + Line_height
  App.screen.check(y, 'jkl', 'F - test_down_arrow_scrolls_down_by_one_screen_line/screen:3')
end
function test_down_arrow_scrolls_down_by_one_screen_line_after_splitting_within_word()
  io.write('\ntest_down_arrow_scrolls_down_by_one_screen_line_after_splitting_within_word')
  -- display the first three lines with the cursor on the bottom line
  App.screen.init{width=25+30, height=60}
  Lines = load_array{'abc', 'def', 'ghijkl', 'mno'}
  Line_width = App.screen.width
  Cursor1 = {line=3, pos=1}
  Screen_top1 = {line=1, pos=1}
  Screen_bottom1 = {}
  App.draw()
  local y = Margin_top
  App.screen.check(y, 'abc', 'F - test_down_arrow_scrolls_down_by_one_screen_line_after_splitting_within_word/baseline/screen:1')
  y = y + Line_height
  App.screen.check(y, 'def', 'F - test_down_arrow_scrolls_down_by_one_screen_line_after_splitting_within_word/baseline/screen:2')
  y = y + Line_height
  App.screen.check(y, 'ghijk', 'F - test_down_arrow_scrolls_down_by_one_screen_line_after_splitting_within_word/baseline/screen:3')
  -- after hitting the down arrow the screen scrolls down by one line
  App.run_after_keychord('down')
  check_eq(Screen_top1.line, 2, 'F - test_down_arrow_scrolls_down_by_one_screen_line_after_splitting_within_word/screen_top')
  check_eq(Cursor1.line, 3, 'F - test_down_arrow_scrolls_down_by_one_screen_line_after_splitting_within_word/cursor:line')
  check_eq(Cursor1.pos, 6, 'F - test_down_arrow_scrolls_down_by_one_screen_line_after_splitting_within_word/cursor:pos')
  y = Margin_top
  App.screen.check(y, 'def', 'F - test_down_arrow_scrolls_down_by_one_screen_line_after_splitting_within_word/screen:1')
  y = y + Line_height
  App.screen.check(y, 'ghijk', 'F - test_down_arrow_scrolls_down_by_one_screen_line_after_splitting_within_word/screen:2')
  y = y + Line_height
  App.screen.check(y, 'l', 'F - test_down_arrow_scrolls_down_by_one_screen_line_after_splitting_within_word/screen:3')
end
function test_page_down_followed_by_down_arrow_does_not_scroll_screen_up()
  io.write('\ntest_page_down_followed_by_down_arrow_does_not_scroll_screen_up')
  App.screen.init{width=25+30, height=60}
  Lines = load_array{'abc', 'def', 'ghijkl', 'mno'}
  Line_width = App.screen.width
  Cursor1 = {line=3, pos=1}
  Screen_top1 = {line=1, pos=1}
  Screen_bottom1 = {}
  App.draw()
  local y = Margin_top
  App.screen.check(y, 'abc', 'F - test_page_down_followed_by_down_arrow_does_not_scroll_screen_up/baseline/screen:1')
  y = y + Line_height
  App.screen.check(y, 'def', 'F - test_page_down_followed_by_down_arrow_does_not_scroll_screen_up/baseline/screen:2')
  y = y + Line_height
  App.screen.check(y, 'ghijk', 'F - test_page_down_followed_by_down_arrow_does_not_scroll_screen_up/baseline/screen:3')
  -- after hitting pagedown the screen scrolls down to start of a long line
  App.run_after_keychord('pagedown')
  check_eq(Screen_top1.line, 3, 'F - test_page_down_followed_by_down_arrow_does_not_scroll_screen_up/baseline2/screen_top')
  check_eq(Cursor1.line, 3, 'F - test_page_down_followed_by_down_arrow_does_not_scroll_screen_up/baseline2/cursor:line')
  check_eq(Cursor1.pos, 1, 'F - test_page_down_followed_by_down_arrow_does_not_scroll_screen_up/baseline2/cursor:pos')
  -- after hitting down arrow the screen doesn't scroll down further, and certainly doesn't scroll up
  App.run_after_keychord('down')
  check_eq(Screen_top1.line, 3, 'F - test_page_down_followed_by_down_arrow_does_not_scroll_screen_up/screen_top')
  check_eq(Cursor1.line, 3, 'F - test_page_down_followed_by_down_arrow_does_not_scroll_screen_up/cursor:line')
  check_eq(Cursor1.pos, 6, 'F - test_page_down_followed_by_down_arrow_does_not_scroll_screen_up/cursor:pos')
  y = Margin_top
  App.screen.check(y, 'ghijk', 'F - test_page_down_followed_by_down_arrow_does_not_scroll_screen_up/screen:1')
  y = y + Line_height
  App.screen.check(y, 'l', 'F - test_page_down_followed_by_down_arrow_does_not_scroll_screen_up/screen:2')
  y = y + Line_height
  App.screen.check(y, 'mno', 'F - test_page_down_followed_by_down_arrow_does_not_scroll_screen_up/screen:3')
end
function test_up_arrow_moves_cursor()
  io.write('\ntest_up_arrow_moves_cursor')
  -- display the first 3 lines with the cursor on the bottom line
  App.screen.init{width=120, height=60}
  Lines = load_array{'abc', 'def', 'ghi', 'jkl'}
  Line_width = 120
  Cursor1 = {line=3, pos=1}
  Screen_top1 = {line=1, pos=1}
  Screen_bottom1 = {}
  App.draw()
  local y = Margin_top
  App.screen.check(y, 'abc', 'F - test_up_arrow_moves_cursor/baseline/screen:1')
  y = y + Line_height
  App.screen.check(y, 'def', 'F - test_up_arrow_moves_cursor/baseline/screen:2')
  y = y + Line_height
  App.screen.check(y, 'ghi', 'F - test_up_arrow_moves_cursor/baseline/screen:3')
  -- after hitting the up arrow the cursor moves up by 1 line
  App.run_after_keychord('up')
  check_eq(Screen_top1.line, 1, 'F - test_up_arrow_moves_cursor/screen_top')
  check_eq(Cursor1.line, 2, 'F - test_up_arrow_moves_cursor/cursor')
  -- the screen is unchanged
  y = Margin_top
  App.screen.check(y, 'abc', 'F - test_up_arrow_moves_cursor/screen:1')
  y = y + Line_height
  App.screen.check(y, 'def', 'F - test_up_arrow_moves_cursor/screen:2')
  y = y + Line_height
  App.screen.check(y, 'ghi', 'F - test_up_arrow_moves_cursor/screen:3')
end
function test_up_arrow_scrolls_up_by_one_line()
  io.write('\ntest_up_arrow_scrolls_up_by_one_line')
  -- display the lines 2/3/4 with the cursor on line 2
  App.screen.init{width=120, height=60}
  Lines = load_array{'abc', 'def', 'ghi', 'jkl'}
  Line_width = 120
  Cursor1 = {line=2, pos=1}
  Screen_top1 = {line=2, pos=1}
  Screen_bottom1 = {}
  App.draw()
  local y = Margin_top
  App.screen.check(y, 'def', 'F - test_up_arrow_scrolls_up_by_one_line/baseline/screen:1')
  y = y + Line_height
  App.screen.check(y, 'ghi', 'F - test_up_arrow_scrolls_up_by_one_line/baseline/screen:2')
  y = y + Line_height
  App.screen.check(y, 'jkl', 'F - test_up_arrow_scrolls_up_by_one_line/baseline/screen:3')
  -- after hitting the up arrow the screen scrolls up by one line
  App.run_after_keychord('up')
  check_eq(Screen_top1.line, 1, 'F - test_up_arrow_scrolls_up_by_one_line/screen_top')
  check_eq(Cursor1.line, 1, 'F - test_up_arrow_scrolls_up_by_one_line/cursor')
  y = Margin_top
  App.screen.check(y, 'abc', 'F - test_up_arrow_scrolls_up_by_one_line/screen:1')
  y = y + Line_height
  App.screen.check(y, 'def', 'F - test_up_arrow_scrolls_up_by_one_line/screen:2')
  y = y + Line_height
  App.screen.check(y, 'ghi', 'F - test_up_arrow_scrolls_up_by_one_line/screen:3')
end
function test_up_arrow_scrolls_up_by_one_screen_line()
  io.write('\ntest_up_arrow_scrolls_up_by_one_screen_line')
  -- display lines starting from second screen line of a line
  App.screen.init{width=25+30, height=60}
  Lines = load_array{'abc', 'def', 'ghi jkl', 'mno'}
  Line_width = App.screen.width
  Cursor1 = {line=3, pos=6}
  Screen_top1 = {line=3, pos=5}
  Screen_bottom1 = {}
  App.draw()
  local y = Margin_top
  App.screen.check(y, 'jkl', 'F - test_up_arrow_scrolls_up_by_one_screen_line/baseline/screen:1')
  y = y + Line_height
  App.screen.check(y, 'mno', 'F - test_up_arrow_scrolls_up_by_one_screen_line/baseline/screen:2')
  -- after hitting the up arrow the screen scrolls up to first screen line
  App.run_after_keychord('up')
  y = Margin_top
  App.screen.check(y, 'ghi ', 'F - test_up_arrow_scrolls_up_by_one_screen_line/screen:1')
  y = y + Line_height
  App.screen.check(y, 'jkl', 'F - test_up_arrow_scrolls_up_by_one_screen_line/screen:2')
  y = y + Line_height
  App.screen.check(y, 'mno', 'F - test_up_arrow_scrolls_up_by_one_screen_line/screen:3')
  check_eq(Screen_top1.line, 3, 'F - test_up_arrow_scrolls_up_by_one_screen_line/screen_top')
  check_eq(Screen_top1.pos, 1, 'F - test_up_arrow_scrolls_up_by_one_screen_line/screen_top')
  check_eq(Cursor1.line, 3, 'F - test_up_arrow_scrolls_up_by_one_screen_line/cursor:line')
  check_eq(Cursor1.pos, 1, 'F - test_up_arrow_scrolls_up_by_one_screen_line/cursor:pos')
end
function test_up_arrow_scrolls_up_to_final_screen_line()
  io.write('\ntest_up_arrow_scrolls_up_to_final_screen_line')
  -- display lines starting just after a long line
  App.screen.init{width=25+30, height=60}
  Lines = load_array{'abc def', 'ghi', 'jkl', 'mno'}
  Line_width = App.screen.width
  Cursor1 = {line=2, pos=1}
  Screen_top1 = {line=2, pos=1}
  Screen_bottom1 = {}
  App.draw()
  local y = Margin_top
  App.screen.check(y, 'ghi', 'F - test_up_arrow_scrolls_up_to_final_screen_line/baseline/screen:1')
  y = y + Line_height
  App.screen.check(y, 'jkl', 'F - test_up_arrow_scrolls_up_to_final_screen_line/baseline/screen:2')
  y = y + Line_height
  App.screen.check(y, 'mno', 'F - test_up_arrow_scrolls_up_to_final_screen_line/baseline/screen:3')
  -- after hitting the up arrow the screen scrolls up to final screen line of previous line
  App.run_after_keychord('up')
  y = Margin_top
  App.screen.check(y, 'def', 'F - test_up_arrow_scrolls_up_to_final_screen_line/screen:1')
  y = y + Line_height
  App.screen.check(y, 'ghi', 'F - test_up_arrow_scrolls_up_to_final_screen_line/screen:2')
  y = y + Line_height
  App.screen.check(y, 'jkl', 'F - test_up_arrow_scrolls_up_to_final_screen_line/screen:3')
  check_eq(Screen_top1.line, 1, 'F - test_up_arrow_scrolls_up_to_final_screen_line/screen_top')
  check_eq(Screen_top1.pos, 5, 'F - test_up_arrow_scrolls_up_to_final_screen_line/screen_top')
  check_eq(Cursor1.line, 1, 'F - test_up_arrow_scrolls_up_to_final_screen_line/cursor:line')
  check_eq(Cursor1.pos, 5, 'F - test_up_arrow_scrolls_up_to_final_screen_line/cursor:pos')
end
function test_up_arrow_scrolls_up_to_empty_line()
  io.write('\ntest_up_arrow_scrolls_up_to_empty_line')
  -- display a screenful of text with an empty line just above it outside the screen
  App.screen.init{width=120, height=60}
  Lines = load_array{'', 'abc', 'def', 'ghi', 'jkl'}
  Line_width = 120
  Cursor1 = {line=2, pos=1}
  Screen_top1 = {line=2, pos=1}
  Screen_bottom1 = {}
  App.draw()
  local y = Margin_top
  App.screen.check(y, 'abc', 'F - test_up_arrow_scrolls_up_to_empty_line/baseline/screen:1')
  y = y + Line_height
  App.screen.check(y, 'def', 'F - test_up_arrow_scrolls_up_to_empty_line/baseline/screen:2')
  y = y + Line_height
  App.screen.check(y, 'ghi', 'F - test_up_arrow_scrolls_up_to_empty_line/baseline/screen:3')
  -- after hitting the up arrow the screen scrolls up by one line
  App.run_after_keychord('up')
  check_eq(Screen_top1.line, 1, 'F - test_up_arrow_scrolls_up_to_empty_line/screen_top')
  check_eq(Cursor1.line, 1, 'F - test_up_arrow_scrolls_up_to_empty_line/cursor')
  y = Margin_top
  -- empty first line
  y = y + Line_height
  App.screen.check(y, 'abc', 'F - test_up_arrow_scrolls_up_to_empty_line/screen:2')
  y = y + Line_height
  App.screen.check(y, 'def', 'F - test_up_arrow_scrolls_up_to_empty_line/screen:3')
end
function test_pageup()
  io.write('\ntest_pageup')
  App.screen.init{width=120, height=45}
  Lines = load_array{'abc', 'def', 'ghi'}
  Line_width = App.screen.width
  Cursor1 = {line=2, pos=1}
  Screen_top1 = {line=2, pos=1}
  Screen_bottom1 = {}
  -- initially the last two lines are displayed
  App.draw()
  local y = Margin_top
  App.screen.check(y, 'def', 'F - test_pageup/baseline/screen:1')
  y = y + Line_height
  App.screen.check(y, 'ghi', 'F - test_pageup/baseline/screen:2')
  -- after pageup the cursor goes to first line
  App.run_after_keychord('pageup')
  check_eq(Screen_top1.line, 1, 'F - test_pageup/screen_top')
  check_eq(Cursor1.line, 1, 'F - test_pageup/cursor')
  y = Margin_top
  App.screen.check(y, 'abc', 'F - test_pageup/screen:1')
  y = y + Line_height
  App.screen.check(y, 'def', 'F - test_pageup/screen:2')
end
function test_pageup_scrolls_up_by_screen_line()
  io.write('\ntest_pageup_scrolls_up_by_screen_line')
  -- display the first three lines with the cursor on the bottom line
  App.screen.init{width=25+30, height=60}
  Lines = load_array{'abc def', 'ghi', 'jkl', 'mno'}
  Line_width = App.screen.width
  Cursor1 = {line=2, pos=1}
  Screen_top1 = {line=2, pos=1}
  Screen_bottom1 = {}
  App.draw()
  local y = Margin_top
  App.screen.check(y, 'ghi', 'F - test_pageup_scrolls_up_by_screen_line/baseline/screen:1')
  y = y + Line_height
  App.screen.check(y, 'jkl', 'F - test_pageup_scrolls_up_by_screen_line/baseline/screen:2')
  y = y + Line_height
  App.screen.check(y, 'mno', 'F - test_pageup_scrolls_up_by_screen_line/baseline/screen:3')  -- line wrapping includes trailing whitespace
  -- after hitting the page-up key the screen scrolls up to top
  App.run_after_keychord('pageup')
  check_eq(Screen_top1.line, 1, 'F - test_pageup_scrolls_up_by_screen_line/screen_top')
  check_eq(Cursor1.line, 1, 'F - test_pageup_scrolls_up_by_screen_line/cursor:line')
  check_eq(Cursor1.pos, 1, 'F - test_pageup_scrolls_up_by_screen_line/cursor:pos')
  y = Margin_top
  App.screen.check(y, 'abc ', 'F - test_pageup_scrolls_up_by_screen_line/screen:1')
  y = y + Line_height
  App.screen.check(y, 'def', 'F - test_pageup_scrolls_up_by_screen_line/screen:2')
  y = y + Line_height
  App.screen.check(y, 'ghi', 'F - test_pageup_scrolls_up_by_screen_line/screen:3')
end
function test_pageup_scrolls_up_from_middle_screen_line()
  io.write('\ntest_pageup_scrolls_up_from_middle_screen_line')
  -- display a few lines starting from the middle of a line (Cursor1.pos > 1)
  App.screen.init{width=25+30, height=60}
  Lines = load_array{'abc def', 'ghi jkl', 'mno'}
  Line_width = App.screen.width
  Cursor1 = {line=2, pos=5}
  Screen_top1 = {line=2, pos=5}
  Screen_bottom1 = {}
  App.draw()
  local y = Margin_top
  App.screen.check(y, 'jkl', 'F - test_pageup_scrolls_up_from_middle_screen_line/baseline/screen:2')
  y = y + Line_height
  App.screen.check(y, 'mno', 'F - test_pageup_scrolls_up_from_middle_screen_line/baseline/screen:3')  -- line wrapping includes trailing whitespace
  -- after hitting the page-up key the screen scrolls up to top
  App.run_after_keychord('pageup')
  check_eq(Screen_top1.line, 1, 'F - test_pageup_scrolls_up_from_middle_screen_line/screen_top')
  check_eq(Cursor1.line, 1, 'F - test_pageup_scrolls_up_from_middle_screen_line/cursor:line')
  check_eq(Cursor1.pos, 1, 'F - test_pageup_scrolls_up_from_middle_screen_line/cursor:pos')
  y = Margin_top
  App.screen.check(y, 'abc ', 'F - test_pageup_scrolls_up_from_middle_screen_line/screen:1')
  y = y + Line_height
  App.screen.check(y, 'def', 'F - test_pageup_scrolls_up_from_middle_screen_line/screen:2')
  y = y + Line_height
  App.screen.check(y, 'ghi ', 'F - test_pageup_scrolls_up_from_middle_screen_line/screen:3')
end
function test_enter_on_bottom_line_scrolls_down()
  io.write('\ntest_enter_on_bottom_line_scrolls_down')
  -- display a few lines with cursor on bottom line
  App.screen.init{width=25+30, height=60}
  Lines = load_array{'abc', 'def', 'ghi', 'jkl'}
  Line_width = App.screen.width
  Cursor1 = {line=3, pos=2}
  Screen_top1 = {line=1, pos=1}
  Screen_bottom1 = {}
  App.draw()
  local y = Margin_top
  App.screen.check(y, 'abc', 'F - test_enter_on_bottom_line_scrolls_down/baseline/screen:1')
  y = y + Line_height
  App.screen.check(y, 'def', 'F - test_enter_on_bottom_line_scrolls_down/baseline/screen:2')
  y = y + Line_height
  App.screen.check(y, 'ghi', 'F - test_enter_on_bottom_line_scrolls_down/baseline/screen:3')
  -- after hitting the enter key the screen scrolls down
  App.run_after_keychord('return')
  check_eq(Screen_top1.line, 2, 'F - test_enter_on_bottom_line_scrolls_down/screen_top')
  check_eq(Cursor1.line, 4, 'F - test_enter_on_bottom_line_scrolls_down/cursor:line')
  check_eq(Cursor1.pos, 1, 'F - test_enter_on_bottom_line_scrolls_down/cursor:pos')
  y = Margin_top
  App.screen.check(y, 'def', 'F - test_enter_on_bottom_line_scrolls_down/screen:1')
  y = y + Line_height
  App.screen.check(y, 'g', 'F - test_enter_on_bottom_line_scrolls_down/screen:2')
  y = y + Line_height
  App.screen.check(y, 'hi', 'F - test_enter_on_bottom_line_scrolls_down/screen:3')
end
function test_enter_on_final_line_avoids_scrolling_down_when_not_at_bottom()
  io.write('\ntest_enter_on_final_line_avoids_scrolling_down_when_not_at_bottom')
  -- display just the bottom line on screen
  App.screen.init{width=25+30, height=60}
  Lines = load_array{'abc', 'def', 'ghi', 'jkl'}
  Line_width = App.screen.width
  Cursor1 = {line=4, pos=2}
  Screen_top1 = {line=4, pos=1}
  Screen_bottom1 = {}
  App.draw()
  local y = Margin_top
  App.screen.check(y, 'jkl', 'F - test_enter_on_final_line_avoids_scrolling_down_when_not_at_bottom/baseline/screen:1')
  -- after hitting the enter key the screen does not scroll down
  App.run_after_keychord('return')
  check_eq(Screen_top1.line, 4, 'F - test_enter_on_final_line_avoids_scrolling_down_when_not_at_bottom/screen_top')
  check_eq(Cursor1.line, 5, 'F - test_enter_on_final_line_avoids_scrolling_down_when_not_at_bottom/cursor:line')
  check_eq(Cursor1.pos, 1, 'F - test_enter_on_final_line_avoids_scrolling_down_when_not_at_bottom/cursor:pos')
  y = Margin_top
  App.screen.check(y, 'j', 'F - test_enter_on_final_line_avoids_scrolling_down_when_not_at_bottom/screen:1')
  y = y + Line_height
  App.screen.check(y, 'kl', 'F - test_enter_on_final_line_avoids_scrolling_down_when_not_at_bottom/screen:2')
end
function test_position_cursor_on_recently_edited_wrapping_line()
  -- draw a line wrapping over 2 screen lines
  io.write('\ntest_position_cursor_on_recently_edited_wrapping_line')
  App.screen.init{width=120, height=200}
  Lines = load_array{'abc def ghi jkl mno pqr ', 'xyz'}
  Line_width = 100
  Cursor1 = {line=1, pos=25}
  Screen_top1 = {line=1, pos=1}
  Screen_bottom1 = {}
  App.draw()
  local y = Margin_top
  -- I don't understand why 120px fits so much on a fake screen, but whatever..
  App.screen.check(y, 'abc def ghi ', 'F - test_position_cursor_on_recently_edited_wrapping_line/baseline1/screen:1')
  y = y + Line_height
  App.screen.check(y, 'jkl mno pqr ', 'F - test_position_cursor_on_recently_edited_wrapping_line/baseline1/screen:2')
  y = y + Line_height
  App.screen.check(y, 'xyz', 'F - test_position_cursor_on_recently_edited_wrapping_line/baseline1/screen:3')
  -- add to the line until it's wrapping over 3 screen lines
  App.run_after_textinput('s')
  App.run_after_textinput('t')
  App.run_after_textinput('u')
  check_eq(Cursor1.pos, 28, 'F - test_move_cursor_using_mouse/cursor:pos')
  y = Margin_top
  App.screen.check(y, 'abc def ghi ', 'F - test_position_cursor_on_recently_edited_wrapping_line/baseline2/screen:1')
  y = y + Line_height
  App.screen.check(y, 'jkl mno pqr ', 'F - test_position_cursor_on_recently_edited_wrapping_line/baseline2/screen:2')
  y = y + Line_height
  App.screen.check(y, 'stu', 'F - test_position_cursor_on_recently_edited_wrapping_line/baseline2/screen:3')
  -- try to move the cursor earlier in the third screen line by clicking the mouse
  local screen_left_margin = 25  -- pixels
  App.run_after_mouserelease(screen_left_margin+8,Margin_top+Line_height*2+5, '1')
  -- cursor should move
  check_eq(Cursor1.line, 1, 'F - test_move_cursor_using_mouse/cursor:line')
  check_eq(Cursor1.pos, 26, 'F - test_move_cursor_using_mouse/cursor:pos')
end
function test_backspace_can_scroll_up()
  io.write('\ntest_backspace_can_scroll_up')
  -- display the lines 2/3/4 with the cursor on line 2
  App.screen.init{width=120, height=60}
  Lines = load_array{'abc', 'def', 'ghi', 'jkl'}
  Line_width = 120
  Cursor1 = {line=2, pos=1}
  Screen_top1 = {line=2, pos=1}
  Screen_bottom1 = {}
  App.draw()
  local y = Margin_top
  App.screen.check(y, 'def', 'F - test_backspace_can_scroll_up/baseline/screen:1')
  y = y + Line_height
  App.screen.check(y, 'ghi', 'F - test_backspace_can_scroll_up/baseline/screen:2')
  y = y + Line_height
  App.screen.check(y, 'jkl', 'F - test_backspace_can_scroll_up/baseline/screen:3')
  -- after hitting backspace the screen scrolls up by one line
  App.run_after_keychord('backspace')
  check_eq(Screen_top1.line, 1, 'F - test_backspace_can_scroll_up/screen_top')
  check_eq(Cursor1.line, 1, 'F - test_backspace_can_scroll_up/cursor')
  y = Margin_top
  App.screen.check(y, 'abcdef', 'F - test_backspace_can_scroll_up/screen:1')
  y = y + Line_height
  App.screen.check(y, 'ghi', 'F - test_backspace_can_scroll_up/screen:2')
  y = y + Line_height
  App.screen.check(y, 'jkl', 'F - test_backspace_can_scroll_up/screen:3')
end
function test_backspace_can_scroll_up_screen_line()
  io.write('\ntest_backspace_can_scroll_up_screen_line')
  -- display lines starting from second screen line of a line
  App.screen.init{width=25+30, height=60}
  Lines = load_array{'abc', 'def', 'ghi jkl', 'mno'}
  Line_width = App.screen.width
  Cursor1 = {line=3, pos=5}
  Screen_top1 = {line=3, pos=5}
  Screen_bottom1 = {}
  App.draw()
  local y = Margin_top
  App.screen.check(y, 'jkl', 'F - test_backspace_can_scroll_up_screen_line/baseline/screen:1')
  y = y + Line_height
  App.screen.check(y, 'mno', 'F - test_backspace_can_scroll_up_screen_line/baseline/screen:2')
  -- after hitting backspace the screen scrolls up by one screen line
  App.run_after_keychord('backspace')
  y = Margin_top
  App.screen.check(y, 'ghijk', 'F - test_backspace_can_scroll_up_screen_line/screen:1')
  y = y + Line_height
  App.screen.check(y, 'l', 'F - test_backspace_can_scroll_up_screen_line/screen:2')
  y = y + Line_height
  App.screen.check(y, 'mno', 'F - test_backspace_can_scroll_up_screen_line/screen:3')
  check_eq(Screen_top1.line, 3, 'F - test_backspace_can_scroll_up_screen_line/screen_top')
  check_eq(Screen_top1.pos, 1, 'F - test_backspace_can_scroll_up_screen_line/screen_top')
  check_eq(Cursor1.line, 3, 'F - test_backspace_can_scroll_up_screen_line/cursor:line')
  check_eq(Cursor1.pos, 4, 'F - test_backspace_can_scroll_up_screen_line/cursor:pos')
end
-- some tests for operating over selections created using Shift- chords
-- we're just testing delete_selection, and it works the same for all keys
function test_backspace_over_selection()
  io.write('\ntest_backspace_over_selection')
  -- select just one character within a line with cursor before selection
  App.screen.init{width=25+30, height=60}
  Lines = load_array{'abc', 'def', 'ghi', 'jkl', 'mno'}
  Line_width = App.screen.width
  Cursor1 = {line=1, pos=1}
  Selection1 = {line=1, pos=2}
  -- backspace deletes the selected character, even though it's after the cursor
  App.run_after_keychord('backspace')
  check_eq(Lines[1].data, 'bc', "F - test_backspace_over_selection/data")
  -- cursor (remains) at start of selection
  check_eq(Cursor1.line, 1, "F - test_backspace_over_selection/cursor:line")
  check_eq(Cursor1.pos, 1, "F - test_backspace_over_selection/cursor:pos")
  -- selection is cleared
  check_nil(Selection1.line, "F - test_backspace_over_selection/selection")
end
function test_backspace_over_selection_reverse()
  io.write('\ntest_backspace_over_selection_reverse')
  -- select just one character within a line with cursor after selection
  App.screen.init{width=25+30, height=60}
  Lines = load_array{'abc', 'def', 'ghi', 'jkl', 'mno'}
  Line_width = App.screen.width
  Cursor1 = {line=1, pos=2}
  Selection1 = {line=1, pos=1}
  -- backspace deletes the selected character
  App.run_after_keychord('backspace')
  check_eq(Lines[1].data, 'bc', "F - test_backspace_over_selection_reverse/data")
  -- cursor moves to start of selection
  check_eq(Cursor1.line, 1, "F - test_backspace_over_selection_reverse/cursor:line")
  check_eq(Cursor1.pos, 1, "F - test_backspace_over_selection_reverse/cursor:pos")
  -- selection is cleared
  check_nil(Selection1.line, "F - test_backspace_over_selection_reverse/selection")
end
function test_backspace_over_multiple_lines()
  io.write('\ntest_backspace_over_multiple_lines')
  -- select just one character within a line with cursor after selection
  App.screen.init{width=25+30, height=60}
  Lines = load_array{'abc', 'def', 'ghi', 'jkl', 'mno'}
  Line_width = App.screen.width
  Cursor1 = {line=1, pos=2}
  Selection1 = {line=4, pos=2}
  -- backspace deletes the region and joins the remaining portions of lines on either side
  App.run_after_keychord('backspace')
  check_eq(Lines[1].data, 'akl', "F - test_backspace_over_multiple_lines/data:1")
  check_eq(Lines[2].data, 'mno', "F - test_backspace_over_multiple_lines/data:2")
  -- cursor remains at start of selection
  check_eq(Cursor1.line, 1, "F - test_backspace_over_multiple_lines/cursor:line")
  check_eq(Cursor1.pos, 2, "F - test_backspace_over_multiple_lines/cursor:pos")
  -- selection is cleared
  check_nil(Selection1.line, "F - test_backspace_over_multiple_lines/selection")
end
function test_backspace_to_end_of_line()
  io.write('\ntest_backspace_to_end_of_line')
  -- select region from cursor to end of line
  App.screen.init{width=25+30, height=60}
  Lines = load_array{'abc', 'def', 'ghi', 'jkl', 'mno'}
  Line_width = App.screen.width
  Cursor1 = {line=1, pos=2}
  Selection1 = {line=1, pos=4}
  -- backspace deletes rest of line without joining to any other line
  App.run_after_keychord('backspace')
  check_eq(Lines[1].data, 'a', "F - test_backspace_to_start_of_line/data:1")
  check_eq(Lines[2].data, 'def', "F - test_backspace_to_start_of_line/data:2")
  -- cursor remains at start of selection
  check_eq(Cursor1.line, 1, "F - test_backspace_to_start_of_line/cursor:line")
  check_eq(Cursor1.pos, 2, "F - test_backspace_to_start_of_line/cursor:pos")
  -- selection is cleared
  check_nil(Selection1.line, "F - test_backspace_to_start_of_line/selection")
end
function test_backspace_to_start_of_line()
  io.write('\ntest_backspace_to_start_of_line')
  -- select region from cursor to start of line
  App.screen.init{width=25+30, height=60}
  Lines = load_array{'abc', 'def', 'ghi', 'jkl', 'mno'}
  Line_width = App.screen.width
  Cursor1 = {line=2, pos=1}
  Selection1 = {line=2, pos=3}
  -- backspace deletes beginning of line without joining to any other line
  App.run_after_keychord('backspace')
  check_eq(Lines[1].data, 'abc', "F - test_backspace_to_start_of_line/data:1")
  check_eq(Lines[2].data, 'f', "F - test_backspace_to_start_of_line/data:2")
  -- cursor remains at start of selection
  check_eq(Cursor1.line, 2, "F - test_backspace_to_start_of_line/cursor:line")
  check_eq(Cursor1.pos, 1, "F - test_backspace_to_start_of_line/cursor:pos")
  -- selection is cleared
  check_nil(Selection1.line, "F - test_backspace_to_start_of_line/selection")
end
function test_undo_insert_text()
  io.write('\ntest_undo_insert_text')
  App.screen.init{width=120, height=60}
  Lines = load_array{'abc', 'def', 'xyz'}
  Line_width = App.screen.width
  Cursor1 = {line=2, pos=4}
  Screen_top1 = {line=1, pos=1}
  Screen_bottom1 = {}
  -- insert a character
  App.run_after_textinput('g')
  check_eq(Cursor1.line, 2, 'F - test_undo_insert_text/baseline/cursor:line')
  check_eq(Cursor1.pos, 5, 'F - test_undo_insert_text/baseline/cursor:pos')
  check_nil(Selection1.line, 'F - test_undo_insert_text/baseline/selection:line')
  check_nil(Selection1.pos, 'F - test_undo_insert_text/baseline/selection:pos')
  local y = Margin_top
  App.screen.check(y, 'abc', 'F - test_undo_insert_text/baseline/screen:1')
  y = y + Line_height
  App.screen.check(y, 'defg', 'F - test_undo_insert_text/baseline/screen:2')
  y = y + Line_height
  App.screen.check(y, 'xyz', 'F - test_undo_insert_text/baseline/screen:3')
  -- undo
  App.run_after_keychord('C-z')
  check_eq(Cursor1.line, 2, 'F - test_undo_insert_text/cursor:line')
  check_eq(Cursor1.pos, 4, 'F - test_undo_insert_text/cursor:pos')
  check_nil(Selection1.line, 'F - test_undo_insert_text/selection:line')
  check_nil(Selection1.pos, 'F - test_undo_insert_text/selection:pos')
  y = Margin_top
  App.screen.check(y, 'abc', 'F - test_undo_insert_text/screen:1')
  y = y + Line_height
  App.screen.check(y, 'def', 'F - test_undo_insert_text/screen:2')
  y = y + Line_height
  App.screen.check(y, 'xyz', 'F - test_undo_insert_text/screen:3')
end
function test_undo_delete_text()
  io.write('\ntest_undo_delete_text')
  App.screen.init{width=120, height=60}
  Lines = load_array{'abc', 'defg', 'xyz'}
  Line_width = App.screen.width
  Cursor1 = {line=2, pos=5}
  Screen_top1 = {line=1, pos=1}
  Screen_bottom1 = {}
  -- delete a character
  App.run_after_keychord('backspace')
  check_eq(Cursor1.line, 2, 'F - test_undo_delete_text/baseline/cursor:line')
  check_eq(Cursor1.pos, 4, 'F - test_undo_delete_text/baseline/cursor:pos')
  check_nil(Selection1.line, 'F - test_undo_delete_text/baseline/selection:line')
  check_nil(Selection1.pos, 'F - test_undo_delete_text/baseline/selection:pos')
  local y = Margin_top
  App.screen.check(y, 'abc', 'F - test_undo_delete_text/baseline/screen:1')
  y = y + Line_height
  App.screen.check(y, 'def', 'F - test_undo_delete_text/baseline/screen:2')
  y = y + Line_height
  App.screen.check(y, 'xyz', 'F - test_undo_delete_text/baseline/screen:3')
  -- undo
--?   -- after undo, the backspaced key is selected
  App.run_after_keychord('C-z')
  check_eq(Cursor1.line, 2, 'F - test_undo_delete_text/cursor:line')
  check_eq(Cursor1.pos, 5, 'F - test_undo_delete_text/cursor:pos')
  check_nil(Selection1.line, 'F - test_undo_delete_text/selection:line')
  check_nil(Selection1.pos, 'F - test_undo_delete_text/selection:pos')
--?   check_eq(Selection1.line, 2, 'F - test_undo_delete_text/selection:line')
--?   check_eq(Selection1.pos, 4, 'F - test_undo_delete_text/selection:pos')
  y = Margin_top
  App.screen.check(y, 'abc', 'F - test_undo_delete_text/screen:1')
  y = y + Line_height
  App.screen.check(y, 'defg', 'F - test_undo_delete_text/screen:2')
  y = y + Line_height
  App.screen.check(y, 'xyz', 'F - test_undo_delete_text/screen:3')
end

File addition: select.lua (----------)

[8.2]

-- helpers for selecting portions of text
local utf8 = require 'utf8'
-- Return any intersection of the region from Selection1 to Cursor1 (or
-- current mouse, if mouse is pressed; or recent mouse if mouse is pressed and
-- currently over a drawing) with the region between {line=line_index, pos=apos}
-- and {line=line_index, pos=bpos}.
-- apos must be less than bpos. However Selection1 and Cursor1 can be in any order.
-- Result: positions spos,epos between apos,bpos.
function Text.clip_selection(line_index, apos, bpos)
  if Selection1.line == nil then return nil,nil end
  -- min,max = sorted(Selection1,Cursor1)
  local minl,minp = Selection1.line,Selection1.pos
  local maxl,maxp
  if love.mouse.isDown('1') then
    maxl,maxp = Text.mouse_pos()
  else
    maxl,maxp = Cursor1.line,Cursor1.pos
  end
  if minl > maxl then
    minl,maxl = maxl,minl
    minp,maxp = maxp,minp
  elseif minl == maxl then
    if minp > maxp then
      minp,maxp = maxp,minp
    end
  end
  -- check if intervals are disjoint
  if line_index < minl then return nil,nil end
  if line_index > maxl then return nil,nil end
  if line_index == minl and bpos <= minp then return nil,nil end
  if line_index == maxl and apos >= maxp then return nil,nil end
  -- compare bounds more carefully (start inclusive, end exclusive)
  local a_ge = Text.le1({line=minl, pos=minp}, {line=line_index, pos=apos})
  local b_lt = Text.lt1({line=line_index, pos=bpos}, {line=maxl, pos=maxp})
--?   print(minl,line_index,maxl, '--', minp,apos,bpos,maxp, '--', a_ge,b_lt)
  if a_ge and b_lt then
    -- fully contained
    return apos,bpos
  elseif a_ge then
    assert(maxl == line_index)
    return apos,maxp
  elseif b_lt then
    assert(minl == line_index)
    return minp,bpos
  else
    assert(minl == maxl and minl == line_index)
    return minp,maxp
  end
end
-- inefficient for some reason, so don't do it on every frame
function Text.mouse_pos()
  local time = love.timer.getTime()
  if Recent_mouse.time and Recent_mouse.time > time-0.1 then
    return Recent_mouse.line, Recent_mouse.pos
  end
  Recent_mouse.time = time
  local line,pos = Text.to_pos(love.mouse.getX(), love.mouse.getY())
  if line then
    Recent_mouse.line = line
    Recent_mouse.pos = pos
  end
  return Recent_mouse.line, Recent_mouse.pos
end
function Text.to_pos(x,y)
  for line_index,line in ipairs(Lines) do
    if line.mode == 'text' then
      if Text.in_line(line, x,y) then
        return line_index, Text.to_pos_on_line(line, x,y)
      end
    end
  end
end
function Text.delete_selection()
  local minl,maxl = minmax(Selection1.line, Cursor1.line)
  local before = snapshot(minl, maxl)
  Text.delete_selection_without_undo()
  record_undo_event({before=before, after=snapshot(Cursor1.line)})
end
function Text.delete_selection_without_undo()
  if Selection1.line == nil then return end
  -- min,max = sorted(Selection1,Cursor1)
  local minl,minp = Selection1.line,Selection1.pos
  local maxl,maxp = Cursor1.line,Cursor1.pos
  if minl > maxl then
    minl,maxl = maxl,minl
    minp,maxp = maxp,minp
  elseif minl == maxl then
    if minp > maxp then
      minp,maxp = maxp,minp
    end
  end
  -- update Cursor1 and Selection1
  Cursor1.line = minl
  Cursor1.pos = minp
  Selection1 = {}
  -- delete everything between min (inclusive) and max (exclusive)
  Lines[minl].fragments = nil
  Lines[minl].screen_line_starting_pos = nil
  local min_offset = utf8.offset(Lines[minl].data, minp)
  local max_offset = utf8.offset(Lines[maxl].data, maxp)
  if minl == maxl then
--?     print('minl == maxl')
    Lines[minl].data = Lines[minl].data:sub(1, min_offset-1)..Lines[minl].data:sub(max_offset)
    return
  end
  assert(minl < maxl)
  local rhs = Lines[maxl].data:sub(max_offset)
  for i=maxl,minl+1,-1 do
    table.remove(Lines, i)
  end
  Lines[minl].data = Lines[minl].data:sub(1, min_offset-1)..rhs
end
function Text.selection()
  if Selection1.line == nil then return end
  -- min,max = sorted(Selection1,Cursor1)
  local minl,minp = Selection1.line,Selection1.pos
  local maxl,maxp = Cursor1.line,Cursor1.pos
  if minl > maxl then
    minl,maxl = maxl,minl
    minp,maxp = maxp,minp
  elseif minl == maxl then
    if minp > maxp then
      minp,maxp = maxp,minp
    end
  end
  local min_offset = utf8.offset(Lines[minl].data, minp)
  local max_offset = utf8.offset(Lines[maxl].data, maxp)
  if minl == maxl then
    return Lines[minl].data:sub(min_offset, max_offset-1)
  end
  assert(minl < maxl)
  local result = Lines[minl].data:sub(min_offset)..'\n'
  for i=minl+1,maxl-1 do
    if Lines[i].mode == 'text' then
      result = result..Lines[i].data..'\n'
    end
  end
  result = result..Lines[maxl].data:sub(1, max_offset-1)
  return result
end
function Text.cut_selection()
  local result = Text.selection()
  Text.delete_selection()
  return result
end

File addition: search.lua (----------)

[8.2]

-- helpers for the search bar (C-f)
function Text.draw_search_bar()
  local h = Line_height+2
  local y = App.screen.height-h
  love.graphics.setColor(0.9,0.9,0.9)
  love.graphics.rectangle('fill', 0, y-10, App.screen.width-1, h+8)
  love.graphics.setColor(0.6,0.6,0.6)
  love.graphics.line(0, y-10, App.screen.width-1, y-10)
  love.graphics.setColor(1,1,1)
  love.graphics.rectangle('fill', 20, y-6, App.screen.width-40, h+2, 2,2)
  love.graphics.setColor(0.6,0.6,0.6)
  love.graphics.rectangle('line', 20, y-6, App.screen.width-40, h+2, 2,2)
  love.graphics.setColor(0,0,0)
  App.screen.print(Search_term, 25,y-5)
  love.graphics.setColor(1,0,0)
  if Search_text == nil then
    Search_text = App.newText(love.graphics.getFont(), Search_term)
  end
  love.graphics.circle('fill', 25+App.width(Search_text),y-5+h, 2)
  love.graphics.setColor(0,0,0)
end
function Text.search_next()
  -- search current line
  local pos = Lines[Cursor1.line].data:find(Search_term, Cursor1.pos)
  if pos then
    Cursor1.pos = pos
  end
  if pos == nil then
    for i=Cursor1.line+1,#Lines do
      pos = Lines[i].data:find(Search_term)
      if pos then
        Cursor1.line = i
        Cursor1.pos = pos
        break
      end
    end
  end
  if pos == nil then
    -- wrap around
    for i=1,Cursor1.line-1 do
      pos = Lines[i].data:find(Search_term)
      if pos then
        Cursor1.line = i
        Cursor1.pos = pos
        break
      end
    end
  end
  if pos == nil then
    Cursor1.line = Search_backup.cursor.line
    Cursor1.pos = Search_backup.cursor.pos
    Screen_top1.line = Search_backup.screen_top.line
    Screen_top1.pos = Search_backup.screen_top.pos
  end
  if Text.lt1(Cursor1, Screen_top1) or Text.lt1(Screen_bottom1, Cursor1) then
    Screen_top1.line = Cursor1.line
    local _, pos = Text.pos_at_start_of_cursor_screen_line()
    Screen_top1.pos = pos
  end
end
function Text.search_previous()
  -- search current line
  local pos = rfind(Lines[Cursor1.line].data, Search_term, Cursor1.pos)
  if pos then
    Cursor1.pos = pos
  end
  if pos == nil then
    for i=Cursor1.line-1,1,-1 do
      pos = rfind(Lines[i].data, Search_term)
      if pos then
        Cursor1.line = i
        Cursor1.pos = pos
        break
      end
    end
  end
  if pos == nil then
    -- wrap around
    for i=#Lines,Cursor1.line+1,-1 do
      pos = rfind(Lines[i].data, Search_term)
      if pos then
        Cursor1.line = i
        Cursor1.pos = pos
        break
      end
    end
  end
  if pos == nil then
    Cursor1.line = Search_backup.cursor.line
    Cursor1.pos = Search_backup.cursor.pos
    Screen_top1.line = Search_backup.screen_top.line
    Screen_top1.pos = Search_backup.screen_top.pos
  end
  if Text.lt1(Cursor1, Screen_top1) or Text.lt1(Screen_bottom1, Cursor1) then
    Screen_top1.line = Cursor1.line
    local _, pos = Text.pos_at_start_of_cursor_screen_line()
    Screen_top1.pos = pos
  end
end
function rfind(s, pat, i)
  local rs = s:reverse()
  local rpat = pat:reverse()
  if i == nil then i = #s end
  local ri = #s - i + 1
  local rendpos = rs:find(rpat, ri)
  if rendpos == nil then return nil end
  local endpos = #s - rendpos + 1
  assert (endpos >= #pat)
  return endpos-#pat+1
end

extract a couple of files

Dependencies

In channels

Change contents

File addition: text_tests.lua (----------)

Replacement in text.lua at line 1 [9.1]

Insertion in text.lua at line 6 [9.1]

Insertion in text.lua at line 9 [9.1]

Deletion in text.lua at line 109 [9.1]

Deletion in text.lua at line 110 [9.1]

Deletion in text.lua at line 118 [9.1]

File addition: select.lua (----------)

File addition: search.lua (----------)