1 files changed, 163 insertions, 0 deletions
diff --git a/util/array.lua b/util/array.lua
new file mode 100644
index 00000000..b78fb98f
--- /dev/null
+++ b/util/array.lua
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+-- 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 setmetatable = setmetatable;
+local math_random = math.random;
+local pairs, ipairs = pairs, ipairs;
+local tostring = tostring;
+
+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(self, t, _s, _var)
+	if type(t) == "function" then -- Assume iterator
+		t = self.collect(t, _s, _var);
+	end
+	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 });
+
+-- Read-only methods
+function array_methods:random()
+	return self[math_random(1,#self)];
+end
+
+-- These methods can be called two ways:
+--   array.method(existing_array, [params [, ...]]) -- Create new array for result
+--   existing_array:method([params, ...]) -- Transform existing array into result
+--
+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
+
+function array_base.pluck(outa, ina, key)
+	for i=1,#ina do
+		outa[i] = ina[i][key];
+	end
+	return outa;
+end
+
+--- These methods only mutate the array
+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
+
+function array_methods:push(x)
+	t_insert(self, x);
+	return self;
+end
+
+function array_methods:pop(x)
+	local v = self[x];
+	t_remove(self, x);
+	return v;
+end
+
+function array_methods:concat(sep)
+	return t_concat(array.map(self, tostring), sep);
+end
+
+function array_methods:length()
+	return #self;
+end
+
+--- These methods always create a new array
+function array.collect(f, s, var)
+	local t = {};
+	while true do
+		var = f(s, var);
+	        if var == nil then break; end
+		t_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;