From 9ffa698e15deed8acbd04507371e7c0e666f1bf1 Mon Sep 17 00:00:00 2001
From: d9k <d9k@ya.ru>
Date: Fri, 4 May 2018 14:52:13 +0300
Subject: Added stackable function `optional()`. ref
 https://github.com/sailorproject/valua/issues/10

---
 valua-test.lua | 11 +++++++----
 valua.lua      | 14 ++++++++++++--
 2 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/valua-test.lua b/valua-test.lua
index e358c77..307cd1a 100644
--- a/valua-test.lua
+++ b/valua-test.lua
@@ -42,13 +42,14 @@ local tests = {
 	{v:new().type("string").len(3,5), {1,false}},
 	{v:new().type("number").len(3,5), {1,false}},
 	{v:new().type("table").empty(), {15,true, 16,false, 1,false}},
+--  require('mobdebug').start('127.0.0.1')
 	{v:new().not_empty(), {2,true, 3,false, 4,false, 16,true, 5,true, 6,true}},
 	{v:new().len(2,10), {2,true}},
 	{v:new().type("number"), {2,false}},
 	{v:new().empty(), {3,true, 4,true, 5,false, 6,false}},
 	{v:new().boolean(), {1,false, 5,true}},
 	{v:new().compare("hey"), {1,false, 2,true}},
-	{v:new().number().min(45), {2,false, 6,false, 7,true}},
+	{v:new().number().min(45), {2,false, 6,false, 7,true, 4,false}},
 	{v:new().number().max(1009), {7,false, 6,true}},
 	{v:new().date(), {9,false, 10,false, 11,true, 8,true}},
 	{v:new().date('us'), {8,false, 9,true}},
@@ -56,12 +57,14 @@ local tests = {
 	{v:new().in_list({"hey",42}), {12,false, 6,true, 2,true}},
 	{v:new().match("^%d+%p%d+%p%d%d%d%d$"), {1,false, 8,true}},
 	{v:new().alnum(), {8,false, 13,true}},
-	{v:new().integer(), {14,false, 6,true}},
-	{v:new().string(), {14,false, 1,true}},
+	{v:new().integer(), {14,false, 6,true,}},
+	{v:new().string(), {14,false, 1,true, 4,false}},
 	{v:new().string().alnum(), {6,false}},
 	{v:new().contains(" "), {2,false, 1,true}},
 	{v:new().no_white(), {1,false, 2,true}},
-	{v:new().datetime(), {19,true, 9,false}}
+	{v:new().datetime(), {19,true, 9,false}},
+  {v:new().number().min(45).optional(), {2,false, 6,false, 7,true, 4,true}},
+  {v:new().string().optional(), {14,false, 1,true, 4,true}},
 }
 
 for n,t in ipairs(tests) do
diff --git a/valua.lua b/valua.lua
index 6e1c6e4..11d4741 100644
--- a/valua.lua
+++ b/valua.lua
@@ -41,8 +41,12 @@ function valua:new(obj)
 		--saves a function named _<index> with its args in a funcs table, to be used later when validating
 		return function(...)
 			local args = pack(...)
-			local f = function(value) return valua['_'..k](value, unpack(args, 1, args.n)) end
-			tinsert(t.funcs,f)
+      if k == 'optional' then
+        obj.allow_nil = true
+      else
+        local f = function(value) return valua['_'..k](value, unpack(args, 1, args.n)) end
+        tinsert(t.funcs,f)
+      end
 			return t
 		end
 	end
@@ -51,6 +55,11 @@ function valua:new(obj)
 	self.__call = function(t,value)
 		local res = true
 		local fres, err
+
+    if value == nil and t.allow_nil then
+      return res, err
+    end
+
 		-- iterates through all chained validations funcs that were packed, passing the value to be validated
 		for _,f in ipairs(t.funcs) do
 			fres,err = f(value)
@@ -64,6 +73,7 @@ function valua:new(obj)
 		return res,err
 	end
 	obj.funcs = {}
+  obj.allow_nil = false
 	return obj
 end
 --
-- 
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