Deleting whitespace at start of string but not at end

Hoi!

So, I've got my programming language parser working pretty mint but then realised that it's removing the whitespace on the end of a line. So if I've got a snippet that looks like this:

<color[red,white]>
<write>
  hey!
  what's up?
</write>
</color>

And I have a space write after 'hey!' on the same line (e.g. 'hey! ') then it will remove the space after 'hey!', which is what I don't want because I want 'what's up?' to appear a space after 'hey!', if you catch my drift.

Here's my current whitespace-removing-technique:

_line:match("^%s*(.-)%s*$")

It removes the whitespace line-by-line.

Any help is appreciated. I'm assuming it's just an alteration to the current 'string:match(..)' I have, but since I'm not familiar with the character codes I cannot figure it out myself (maybe remove '(.-)%s*$' at the end?).

Here's what I use:

– http://snippets.luac..._from_string_76

function trim(s)
  return s:find'^%s*$' and '' or s:match'^%s*(.*%S)'
end

-- trim whitespace from left end of string
function triml(s)
  return s:match'^%s*(.*)'
end

-- trim whitespace from right end of string
function trimr(s)
  return s:find'^%s*$' and '' or s:match'^(.*%S)'
end

If I understand what you're asking, here's a quick solution I thought up. My Lua skills are rusty, but the test scenario you described checks out.

local codeSnippet =
[[
hey!
what's up?
]]

local function parseLineTrimWhiteSpaceAtBackKeepAtFront(line)
   return line:match("[%s]*([^%s]*%s*)")
end

local function parseSnippetIntoSingleLine(codeSnippet)
   local parsedLines = {}
   local lineNumber = 1
   for line in codeSnippet:gmatch("[^\n+]+") do
	  parsedLines[lineNumber] = line
	  lineNumber = lineNumber + 1
   end
   return parsedLines
end

local function combineParsedLinesIntoSingleLine(parsedLines)
   local combinedLine = ""
   for _, line in ipairs(parsedLines) do
	   combinedLine = combinedLine .. line
   end
   return combinedLine
end

local function getContentLineFromCodeSnippet(codeSnippet)
   local parsedLines = parseSnippetIntoSingleLine(codeSnippet)
   return combineParsedLinesIntoSingleLine(parsedLines)
end

print(getContentLineFromCodeSnippet(codeSnippet))
-- Output (quotes to define string start/stop): "hey! what's up?"