require 'colorize'

--?   print('== line', line_index, '^'..line.data..'$')

  initialize_color()

    App.color(Text_color)

    select_color(frag)

function find(s, pat, i)

function find(s, pat, i, plain)

  return s:find(pat, i)

  return s:find(pat, i, plain)

function rfind(s, pat, i)

function rfind(s, pat, i, plain)

  local rendpos = rs:find(rpat, ri)

  local rendpos = rs:find(rpat, ri, plain)

-- State transitions while colorizing a single line.
-- Just for comments and strings.
-- Limitation: each fragment gets a uniform color so we can only change color
-- at word boundaries.
Next_state = {
  normal={
    {prefix='--', target='comment'},
    {prefix='"', target='dstring'},
    {prefix="'", target='sstring'},
  },
  dstring={
    {suffix='"', target='normal'},
  },
  sstring={
    {suffix="'", target='normal'},
  },
  -- comments are a sink
}
Comments_color = {r=0, g=0, b=1}
String_color = {r=0, g=0.5, b=0.5}
Colors = {
  normal=Text_color,
  comment=Comments_color,
  sstring=String_color,
  dstring=String_color
}
Current_state = 'normal'
function initialize_color()
--?   print('new line')
  Current_state = 'normal'
end
function select_color(frag)
  switch_color(frag)
--?   print('using color', Current_state, Colors[Current_state])
  App.color(Colors[Current_state])
end
function switch_color(frag)
--?   print('switch', frag, Current_state, Next_state[Current_state])
  if Next_state[Current_state] == nil then
    return
  end
  for _,edge in pairs(Next_state[Current_state]) do
--?     print(Current_state, 'checking for transition', frag, edge.prefix)
    if edge.prefix and find(frag, edge.prefix, nil, --[[plain]] true) == 1 then
      Current_state = edge.target
--?       print('switching to', Current_state)
      break
    elseif edge.suffix and rfind(frag, edge.suffix, nil, --[[plain]] true) == #frag then
      Current_state = edge.target
--?       print('switching to', Current_state)
      break
    end
  end
end