reduce use of rfind

Dependencies

• [2] 6K5PFF6X helper: trimming whitespace from strings
• [3] DW6SNODM source editing: highlight [[ ]] comments/strings
• [4] KKMFQDR4 editing source code from within the app
• [*] BULPIBEG beginnings of a module for the text editor
• [*] PLKNHYZ4 extract a function
• [*] LXTTOB33 extract a couple of files

Change contents

• edit in text.lua at line 1003
  [2.172]

  [7.438]
  + end

  +

  + function starts_with(s, prefix)

  + if #s < #prefix then

  + return false

  + end

  + for i=1,#prefix do

  + if s:sub(i,i) ~= prefix:sub(i,i) then

  + return false

  + end

  + end

  + return true

  + end

  +

  + function ends_with(s, suffix)

  + if #s < #suffix then

  + return false

  + end

  + for i=0,#suffix-1 do

  + if s:sub(#s-i,#s-i) ~= suffix:sub(#suffix-i,#suffix-i) then

  + return false

  + end

  + end

  + return true
• edit in search.lua at line 119
  [8.51767]

  [4.177926]
  + -- TODO: avoid the expensive reverse() operations

  + -- Particularly if we only care about literal matches, we don't need all of string.find
• replacement in colorize.lua at line 63
  [4.209036]→[4.209036:209116](∅→∅)
  − if edge.prefix and find(frag, edge.prefix, nil, --[[plain]] true) == 1 then
  [4.209036]

  [4.209116]
  + if edge.prefix and starts_with(frag, edge.prefix) then
• replacement in colorize.lua at line 76
  [4.209358]→[3.439:543](∅→∅)
  − if edge.suffix and rfind(frag, edge.suffix, nil, --[[plain]] true) == #frag - #edge.suffix + 1 then
  [4.209358]

  [4.209443]
  + if edge.suffix and ends_with(frag, edge.suffix) then
• edit in colorize.lua at line 81
  [4.209503]→[4.209503:209672](∅→∅)
  − end

  −

  − function trim(s)

  − return s:gsub('^%s+', ''):gsub('%s+$', '')

  − end

  −

  − function ltrim(s)

  − return s:gsub('^%s+', '')

  − end

  −

  − function rtrim(s)

  − return s:gsub('%s+$', '')