array.lua

-- Prosody IM

-- Copyright (C) 2008-2010 Matthew Wild

-- Copyright (C) 2008-2010 Waqas Hussain

-- 

-- This project is MIT/X11 licensed. Please see the

-- COPYING file in the source package for more information.

--

local t_insert, t_sort, t_remove, t_concat 

	= table.insert, table.sort, table.remove, table.concat;

local array = {};

local array_base = {};

local array_methods = {};

local array_mt = { __index = array_methods, __tostring = function (array) return array:concat(", "); end };

local function new_array(_, t)

	return setmetatable(t or {}, array_mt);

end

function array_mt.__add(a1, a2)

	local res = new_array();

	return res:append(a1):append(a2);

end

setmetatable(array, { __call = new_array });

function array_base.map(outa, ina, func)

	for k,v in ipairs(ina) do

		outa[k] = func(v);

	end

	return outa;

end

function array_base.filter(outa, ina, func)

	local inplace, start_length = ina == outa, #ina;

	local write = 1;

	for read=1,start_length do

		local v = ina[read];

		if func(v) then

			outa[write] = v;

			write = write + 1;

		end

	end

	if inplace and write <= start_length then

		for i=write,start_length do

			outa[i] = nil;

		end

	end

	return outa;

end

function array_base.sort(outa, ina, ...)

	if ina ~= outa then

		outa:append(ina);

	end

	t_sort(outa, ...);

	return outa;

end

--- These methods only mutate

function array_methods:random()

	return self[math.random(1,#self)];

end

function array_methods:shuffle(outa, ina)

	local len = #self;

	for i=1,#self do

		local r = math.random(i,len);

		self[i], self[r] = self[r], self[i];

	end

	return self;

end

function array_methods:reverse()

	local len = #self-1;

	for i=len,1,-1 do

		self:push(self[i]);

		self:pop(i);

	end

	return self;

end

function array_methods:append(array)

	local len,len2  = #self, #array;

	for i=1,len2 do

		self[len+i] = array[i];

	end

	return self;

end

array_methods.push = table.insert;

array_methods.pop = table.remove;

array_methods.concat = table.concat;

array_methods.length = function (t) return #t; end

--- These methods always create a new array

function array.collect(f, s, var)

	local t, var = {};

	while true do

		var = f(s, var);

	        if var == nil then break; end

		table.insert(t, var);

	end

	return setmetatable(t, array_mt);

end

---

-- Setup methods from array_base

for method, f in pairs(array_base) do

	local base_method = f;

	-- Setup global array method which makes new array

	array[method] = function (old_a, ...)

		local a = new_array();

		return base_method(a, old_a, ...);

	end

	-- Setup per-array (mutating) method

	array_methods[method] = function (self, ...)

		return base_method(self, self, ...);

	end

end

_G.array = array;

module("array");

return array;