inifile/inifile.lua

local inifile = {
	_VERSION = "inifile 1.0",
	_DESCRIPTION = "Inifile is a simple, complete ini parser for lua",
	_URL = "http://docs.bartbes.com/inifile",
	_LICENSE = [[
		Copyright 2011-2015 Bart van Strien. All rights reserved.

		Redistribution and use in source and binary forms, with or without modification, are
		permitted provided that the following conditions are met:

		   1. Redistributions of source code must retain the above copyright notice, this list of
			  conditions and the following disclaimer.

		   2. Redistributions in binary form must reproduce the above copyright notice, this list
			  of conditions and the following disclaimer in the documentation and/or other materials
			  provided with the distribution.

		THIS SOFTWARE IS PROVIDED BY BART VAN STRIEN ''AS IS'' AND ANY EXPRESS OR IMPLIED
		WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
		FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL BART VAN STRIEN OR
		CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
		CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
		SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
		ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
		NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
		ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

		The views and conclusions contained in the software and documentation are those of the
		authors and should not be interpreted as representing official policies, either expressed
		or implied, of Bart van Strien.
	]] -- The above license is known as the Simplified BSD license.
}

local defaultBackend = "io"

local backends = {
	io = {
		lines = function(name) return assert(io.open(name)):lines() end,
		write = function(name, contents) assert(io.open(name, "w")):write(contents) end,
	},
	memory = {
		lines = function(text) return text:gmatch("([^\r\n]+)\r?\n") end,
		write = function(name, contents) return contents end,
	},
}

if love then
	backends.love = {
		lines = love.filesystem.lines,
		write = function(name, contents) love.filesystem.write(name, contents) end,
	}
	defaultBackend = "love"
end

function inifile.parse(name, backend)
	backend = backend or defaultBackend
	local t = {}
	local section
	local comments = {}
	local sectionorder = {}
	local cursectionorder
	local lineNumber = 0
	local errors = {}

	for line in backends[backend].lines(name) do
		lineNumber = lineNumber + 1
		local validLine = false

		-- Section headers
		local s = line:match("^%[([^%]]+)%]$")
		if s then
			section = s
			t[section] = t[section] or {}
			cursectionorder = {name = section}
			table.insert(sectionorder, cursectionorder)
			validLine = true
		end

		-- Comments
		s = line:match("^;(.+)$")
		if s then
			local commentsection = section or comments
			comments[commentsection] = comments[commentsection] or {}
			table.insert(comments[commentsection], s)
			validLine = true
		end

		-- Key-value pairs
		local key, value = line:match("^([%w_]+)%s-=%s-(.+)$")
		if tonumber(value) then value = tonumber(value) end
		if value == "true" then value = true end
		if value == "false" then value = false end
		if key and value ~= nil and section ~= nil then
			t[section][key] = value
			table.insert(cursectionorder, key)
			validLine = true
		end

		if not validLine then
			table.insert(errors, ("Line %d: Invalid data found '%s'"):format(lineNumber, line))
		end
	end

	-- Store our metadata in the __inifile field in the metatable
	return setmetatable(t, {
		__inifile = {
			comments = comments,
			sectionorder = sectionorder,
		}
	}), errors
end

function inifile.save(name, t, backend)
	backend = backend or defaultBackend
	local contents = {}

	-- Get our metadata if it exists
	local metadata = getmetatable(t)
	local comments, sectionorder

	if metadata then metadata = metadata.__inifile end
	if metadata then
		comments = metadata.comments
		sectionorder = metadata.sectionorder
	end

	-- If there are comments before sections,
	-- write them out now
	if comments and comments[comments] then
		for i, v in ipairs(comments[comments]) do
			table.insert(contents, (";%s"):format(v))
		end
		table.insert(contents, "")
	end

	local function writevalue(section, key)
		local value = section[key]
		-- Discard if it doesn't exist (anymore)
		if value == nil then return end
		table.insert(contents, ("%s=%s"):format(key, tostring(value)))
	end

	local function tableLike(value)
		local function index()
			return value[1]
		end

		return pcall(index) and pcall(next, value)
	end

	local function writesection(section, order)
		local s = t[section]
		-- Discard if it doesn't exist (anymore)
		if not s then return end
		table.insert(contents, ("[%s]"):format(section))

		assert(tableLike(s), ("Invalid section %s: not table-like"):format(section))

		-- Write our comments out again, sadly we have only achieved
		-- section-accuracy so far
		if comments and comments[section] then
			for i, v in ipairs(comments[section]) do
				table.insert(contents, (";%s"):format(v))
			end
		end

		-- Write the key-value pairs with optional order
		local done = {}
		if order then
			for _, v in ipairs(order) do
				done[v] = true
				writevalue(s, v)
			end
		end
		for i, _ in pairs(s) do
			if not done[i] then
				writevalue(s, i)
			end
		end

		-- Newline after the section
		table.insert(contents, "")
	end

	-- Write the sections, with optional order
	local done = {}
	if sectionorder then
		for _, v in ipairs(sectionorder) do
			done[v.name] = true
			writesection(v.name, v)
		end
	end
	-- Write anything that wasn't ordered
	for i, _ in pairs(t) do
		if not done[i] then
			writesection(i)
		end
	end

	return backends[backend].write(name, table.concat(contents, "\n"))
end

return inifile