Module:Underscore

-- Copyright (c) 2009 Marcus Irven -- -- 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.

--- Underscore is a set of utility functions for dealing with -- iterators, arrays, tables, and functions.

local Underscore = { funcs = {} } Underscore.__index = Underscore

function Underscore.__call(_, value) return Underscore:new(value) end

function Underscore:new(value, chained) return setmetatable({ _val = value, chained = chained or false }, self) end

function Underscore.iter(list_or_iter) if type(list_or_iter) == "function" then return list_or_iter end

local i = 0 return function if i < #list_or_iter then i = i + 1 return list_or_iter[i] end end end

function Underscore.range(start_i, end_i, step) if end_i == nil then end_i = start_i start_i = 1 end step = step or 1

local i = start_i local range_iter = function if i <= end_i then local val = i			i = i + step return val end end return Underscore:new(range_iter) end

--- Identity function. This function looks useless, but is used throughout Underscore as a default. -- @name _.identity -- @param value any object -- @return value -- @usage _.identity("foo") -- => "foo" function Underscore.identity(value) return value end

-- chaining

function Underscore:chain self.chained = true return self end

function Underscore:value return self._val end

-- iter

function Underscore.funcs.each(list, func) for i in Underscore.iter(list) do		func(i) end return list end

function Underscore.funcs.map(list, func) local mapped = {} for i in Underscore.iter(list) do		mapped[#mapped+1] = func(i) end return mapped end

function Underscore.funcs.reduce(list, memo, func) for i in Underscore.iter(list) do		memo = func(memo, i)	end return memo end

function Underscore.funcs.detect(list, func) for i in Underscore.iter(list) do		if func(i) then return i end end return nil end

function Underscore.funcs.select(list, func) local selected = {} for i in Underscore.iter(list) do		if func(i) then selected[#selected+1] = i end end return selected end

function Underscore.funcs.reject(list, func) local selected = {} for i in Underscore.iter(list) do		if not func(i) then selected[#selected+1] = i end end return selected end

function Underscore.funcs.all(list, func) func = func or Underscore.identity -- TODO what should happen with an empty list? for i in Underscore.iter(list) do		if not func(i) then return false end end return true end

function Underscore.funcs.any(list, func) func = func or Underscore.identity

-- TODO what should happen with an empty list? for i in Underscore.iter(list) do		if func(i) then return true end end return false end

function Underscore.funcs.include(list, value) for i in Underscore.iter(list) do		if i == value then return true end end return false end

function Underscore.funcs.invoke(list, function_name, ...) local args = {...} Underscore.funcs.each(list, function(i) i[function_name](i, unpack(args)) end) return list end

function Underscore.funcs.pluck(list, propertyName) return Underscore.funcs.map(list, function(i) return i[propertyName] end) end

function Underscore.funcs.min(list, func) func = func or Underscore.identity return Underscore.funcs.reduce(list, { item = nil, value = nil }, function(min, item) 		if min.item == nil then			min.item = item			min.value = func(item)		else			local value = func(item)			if value < min.value then				min.item = item				min.value = value			end		end		return min	end).item end

function Underscore.funcs.max(list, func) func = func or Underscore.identity return Underscore.funcs.reduce(list, { item = nil, value = nil }, function(max, item) 		if max.item == nil then			max.item = item			max.value = func(item)		else			local value = func(item)			if value > max.value then				max.item = item				max.value = value			end		end		return max	end).item end

function Underscore.funcs.to_array(list) local array = {} for i in Underscore.iter(list) do		array[#array+1] = i	end return array end

function Underscore.funcs.reverse(list) local reversed = {} for i in Underscore.iter(list) do		table.insert(reversed, 1, i)	end return reversed end

function Underscore.funcs.sort(iter, comparison_func) local array = iter if type(iter) == "function" then array = Underscore.funcs.to_array(iter) end table.sort(array, comparison_func) return array end

-- arrays

function Underscore.funcs.first(array, n)	if n == nil then return array[1] else local first = {} n = math.min(n,#array) for i=1,n do			first[i] = array[i] end return first end end

function Underscore.funcs.rest(array, index) index = index or 2 local rest = {} for i=index,#array do		rest[#rest+1] = array[i] end return rest end

function Underscore.funcs.slice(array, start_index, length) local sliced_array = {} start_index = math.max(start_index, 1) local end_index = math.min(start_index+length-1, #array) for i=start_index, end_index do		sliced_array[#sliced_array+1] = array[i] end return sliced_array end

function Underscore.funcs.flatten(array) local all = {} for ele in Underscore.iter(array) do		if type(ele) == "table" then local flattened_element = Underscore.funcs.flatten(ele) Underscore.funcs.each(flattened_element, function(e) all[#all+1] = e end) else all[#all+1] = ele end end return all end

function Underscore.funcs.push(array, item) table.insert(array, item) return array end

function Underscore.funcs.pop(array) return table.remove(array) end

function Underscore.funcs.shift(array) return table.remove(array, 1) end

function Underscore.funcs.unshift(array, item) table.insert(array, 1, item) return array end

function Underscore.funcs.join(array, separator) return table.concat(array, separator) end

-- objects

function Underscore.funcs.keys(obj) local keys = {} for k,v in pairs(obj) do		keys[#keys+1] = k	end return keys end

function Underscore.funcs.values(obj) local values = {} for k,v in pairs(obj) do		values[#values+1] = v	end return values end

function Underscore.funcs.extend(destination, source) for k,v in pairs(source) do		destination[k] = v	end return destination end

function Underscore.funcs.is_empty(obj) return next(obj) == nil end

-- Originally based on penlight's deepcompare -- http://luaforge.net/projects/penlight/ function Underscore.funcs.is_equal(o1, o2, ignore_mt) local ty1 = type(o1) local ty2 = type(o2) if ty1 ~= ty2 then return false end -- non-table types can be directly compared if ty1 ~= 'table' then return o1 == o2 end -- as well as tables which have the metamethod __eq local mt = getmetatable(o1) if not ignore_mt and mt and mt.__eq then return o1 == o2 end local is_equal = Underscore.funcs.is_equal for k1,v1 in pairs(o1) do		local v2 = o2[k1] if v2 == nil or not is_equal(v1,v2, ignore_mt) then return false end end for k2,v2 in pairs(o2) do		local v1 = o1[k2] if v1 == nil then return false end end return true end

-- functions

function Underscore.funcs.compose(...) local function call_funcs(funcs, ...) if #funcs > 1 then return funcs[1](call_funcs(_.rest(funcs), ...)) else return funcs[1](...) end end local funcs = {...} return function(...) return call_funcs(funcs, ...) end end

function Underscore.funcs.wrap(func, wrapper) return function(...) return wrapper(func, ...) end end

function Underscore.funcs.curry(func, argument) return function(...) return func(argument, ...) end end

function Underscore.functions return Underscore.keys(Underscore.funcs) end

-- add aliases Underscore.methods = Underscore.functions

Underscore.funcs.for_each = Underscore.funcs.each Underscore.funcs.collect = Underscore.funcs.map Underscore.funcs.inject = Underscore.funcs.reduce Underscore.funcs.foldl = Underscore.funcs.reduce Underscore.funcs.filter = Underscore.funcs.select Underscore.funcs.every = Underscore.funcs.all Underscore.funcs.some = Underscore.funcs.any Underscore.funcs.head = Underscore.funcs.first Underscore.funcs.tail = Underscore.funcs.rest

local function wrap_functions_for_oo_support local function value_and_chained(value_or_self) local chained = false if getmetatable(value_or_self) == Underscore then chained = value_or_self.chained value_or_self = value_or_self._val end return value_or_self, chained end

local function value_or_wrap(value, chained) if chained then value = Underscore:new(value, true) end return value end

for fn, func in pairs(Underscore.funcs) do		Underscore[fn] = function(obj_or_self, ...) local obj, chained = value_and_chained(obj_or_self) return value_or_wrap(func(obj, ...), chained) end end end

wrap_functions_for_oo_support

return Underscore:new