Converting a phrase to an acronym

[Demeth]

function Acrobot_SubChecker(msg) 
	local SubStatus = nil
	local UnconvertedAcro = msg
	DEFAULT_CHAT_FRAME:AddMessage("Unconverted Acro:" .. UnconvertedAcro) --This successfully displays the phrase being passed to the function
	local ConvertedAcroTable = {}
	for part in string.gmatch(UnconvertedAcro, "%a+") do
		AbbreviatedAcro = string.sub(part, 1, 1)
		table.insert(ConvertedAcroTable, AbbreviatedAcro)
	end
	ConvertedAcroString = table.concat(ConvertedAcroTable)
	DEFAULT_CHAT_FRAME:AddMessage(ConvertedAcroString .. " " .. Acrobot_CreateAnswer("current")) --This is where it fails with the error "attempt to concatenate a nil value"
	if string.lower(ConvertedAcroString) == Acrobot_CreateAnswer("current") then		
		SubStatus = "Accepted"
		return SubStatus
	elseif string.lower(ConvertedAcroString) ~= Acrobot_CreateAnswer("current") then
		SubStatus = "Rejected"
		return SubStatus
	end
end

The code I pasted above is intended to take a phrase and convert it into an acronym. For example, the phrase "Demeth likes WoWInterface" would become "dlw". However, it's refusing to work, and I'm out of ideas.

This is my first "real" addon by the way.

[Seerah]

The way that I would do it would be to split the string wherever a space occurs, then take each word and chop off everything but the first letter. Then you'll need to put them back together, and string.lower or string.upper depending on how you want it formatted.

local phrase = "Dameth likes WoWInterface"
local words = {strsplit(" ", phrase)}
local letters = {}
for i = 1, #words do
     letters[i] = strsub(words[i], 1, 1)
end
local abbr = strconcat(unpack(letters))

The above is *totally* untested and not written by a pro.

[Demeth]

It works, thanks!