This script turns a style.css generated by icomoon into a lua table with the UTF-8 strings for each icon

instructions.md

In order to use this lib:

• Go to the Icomoon app
• Select your icons (you can use a selection.json file with the button)
• Click on the "Font" button
• Set your preferences to:
• Class Prefix = icon-
• Class Postfix = ``
• Css Selector = "Use i (for selecting )"
• Set your Codes to Basic Latin
• Download
• Grab the style.css from the downloaded .zip and place it inside a folder next to the styletolua.lua file.
• Create a file called main.lua and write this inside of it:

love.load = function ()
	require "styletolua" ("style.css")
	love.system.openURL("file://"..love.filesystem.getSaveDirectory())
	love.event.quit()
end

• Drag the folder where the style.css, styletolua.lua and main.lua are, on top of the LÖVE executable
• It should open the folder containing the icons.lua file

Take into account that the table generated has the raw names, that is without the prepended icon-, so if you use the demo.html as a reference of the icons, remember to remove the icon- from the beginning of the name

styletolua.lua

--[[
	Ser: Copyright 2011,2013 Robin Wellner (MIT License)
	StyleToTable: Copyright 2015 Pablo Mayobre (MIT License)
	
	Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

	The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
]]

local pairs, ipairs, tostring, type, concat, dump, floor = pairs, ipairs, tostring, type, table.concat, string.dump, math.floor

local function getchr(c)
	return "\\" .. c:byte()
end

local function make_safe(text)
	return ("%q"):format(text):gsub('\n', 'n'):gsub("[\128-\255]", getchr)
end

local oddvals = {[tostring(1/0)] = '1/0', [tostring(-1/0)] = '-1/0', [tostring(0/0)] = '0/0'}
local function write(t, memo, rev_memo)
	local ty = type(t)
	if ty == 'number' or ty == 'boolean' or ty == 'nil' then
		t = tostring(t)
		return oddvals[t] or t
	elseif ty == 'string' then
		return make_safe(t)
	elseif ty == 'table' or ty == 'function' then
		if not memo[t] then
			local index = #rev_memo + 1
			memo[t] = index
			rev_memo[index] = t
		end
		return '_[' .. memo[t] .. ']'
	else
		error("Trying to serialize unsupported type " .. ty)
	end
end

local kw = {['and'] = true, ['break'] = true, ['do'] = true, ['else'] = true,
	['elseif'] = true, ['end'] = true, ['false'] = true, ['for'] = true,
	['function'] = true, ['goto'] = true, ['if'] = true, ['in'] = true,
	['local'] = true, ['nil'] = true, ['not'] = true, ['or'] = true,
	['repeat'] = true, ['return'] = true, ['then'] = true, ['true'] = true,
	['until'] = true, ['while'] = true}
local function write_key_value_pair(k, v, memo, rev_memo, name)
	if type(k) == 'string' and k:match '^[_%a][_%w]*$' and not kw[k] then
		return (name and name or '') .. '["' .. k ..'"] = ' .. write(v, memo, rev_memo)
	else
		return (name or '') .. '[' .. write(k, memo, rev_memo) .. '] = ' .. write(v, memo, rev_memo)
	end
end

-- fun fact: this function is not perfect
-- it has a few false positives sometimes
-- but no false negatives, so that's good
local function is_cyclic(memo, sub, super)
	local m = memo[sub]
	local p = memo[super]
	return m and p and m < p
end

local function write_table_ex(t, memo, rev_memo, srefs, name)
	if type(t) == 'function' then
		return '_[' .. name .. '] = loadstring ' .. make_safe(dump(t))
	end
	local m = {'_[', name, '] = {\n\t'}
	local mi = 3
	for i = 1, #t do -- don't use ipairs here, we need the gaps
		local v = t[i]
		if v == t or is_cyclic(memo, v, t) then
			srefs[#srefs + 1] = {name, i, v}
			m[mi + 1] = 'nil,\n\t'
			mi = mi + 1
		else
			m[mi + 1] = write(v, memo, rev_memo)
			m[mi + 2] = ',\n\t'
			mi = mi + 2
		end
	end
	for k,v in pairs(t) do
		if type(k) ~= 'number' or floor(k) ~= k or k < 1 or k > #t then
			if v == t or k == t or is_cyclic(memo, v, t) or is_cyclic(memo, k, t) then
				srefs[#srefs + 1] = {name, k, v}
			else
				m[mi + 1] = write_key_value_pair(k, v, memo, rev_memo)
				m[mi + 2] = ',\n\t'
				mi = mi + 2
			end
		end
	end
	m[mi > 3 and mi or mi + 1] = '\n}\n'
	return concat(m)
end

local serialize = function(t)
	local memo = {[t] = 0}
	local rev_memo = {[0] = t}
	local srefs = {}
	local result = {}

	-- phase 1: recursively descend the table structure
	local n = 0
	while rev_memo[n] do
		result[n + 1] = write_table_ex(rev_memo[n], memo, rev_memo, srefs, n)
		n = n + 1
	end

	-- phase 2: reverse order
	for i = 1, n*.5 do
		local j = n - i + 1
		result[i], result[j] = result[j], result[i]
	end

	-- phase 3: add all the tricky cyclic stuff
	for i, v in ipairs(srefs) do
		n = n + 1
		result[n] = write_key_value_pair(v[2], v[3], memo, rev_memo, '_[' .. v[1] .. ']')
	end

	-- phase 4: add something about returning the main table
	if result[n]:sub(1, 5) == '_[0] ' then
		result[n] = 'local icons = ' .. result[n]:sub(7)
		result[n + 1] = [[return setmetatable(icons,{
	__call = function (self,...)
		local s = ""
		local unpack = table.unpack or unpack
		for k,v in ipairs{...} do
			if type(v) == "table" then
				s = s..self(unpack(v))
			else
				s = s .. self[v]
			end
		end
		return s
	end
})]]
	else
		result[n + 1] = [[return setmetatable(_[0],{
	__call = function (self,...)
		local s = ""
		local unpack = table.unpack or unpack
		for k,v in ipairs{...} do
			if type(v) == "table" then
				s = s..self(unpack(v))
			else
				s = s .. self[v]
			end
		end
		return s
	end
})]]
	end

	-- phase 5: just concatenate everything
	result = concat(result, '\n')
	return n > 1 and 'local _ = {}\n' .. result or result
end

return function (f)
	local css = love.filesystem.read(f)

	css = "return {\n"..css:gsub(
		"%@font%-face %{.-%}",""
	):gsub(
		"i %{.-%}",""
	):gsub(
		"%.icon%-",'\t%[%"'
	):gsub(
		'%:before %{\n\tcontent%: %"%\\','%"%] %= 0x'
	):gsub(
		'%"%;\n%}',';\n'
	).."\n}"

	local s = loadstring and loadstring(css)() or load(css)()

	for k,v in pairs(s) do
		if v < 0x80 then
			s[k] = string.char(v)
		else
			local y,x = math.floor(v/64) + 192,v%64 + 128
			s[k] = string.char(y,x)
		end
	end

	love.filesystem.write("icons.lua","--Generated with StyleToLua https://gist.github.com/Positive07/79cee2ae97bbcc8dc760\n\n"..serialize(s))
end