From d7df81b9ae8b6074aa281d9412cbdaf93a84be87 Mon Sep 17 00:00:00 2001
From: Nicolas Cannasse <ncannasse@gmail.com>
Date: Thu, 11 Sep 2014 18:13:38 +0200
Subject: [PATCH] added optional parameters support

---
 hscript/Expr.hx   |  4 +++-
 hscript/Interp.hx | 28 +++++++++++++++++++++++++++-
 hscript/Parser.hx | 21 ++++++++++++++-------
 3 files changed, 44 insertions(+), 9 deletions(-)

diff --git a/hscript/Expr.hx b/hscript/Expr.hx
index ed31aea..1bab2c7 100644
--- a/hscript/Expr.hx
+++ b/hscript/Expr.hx
@@ -57,7 +57,7 @@ enum Expr {
 	EFor( v : String, it : Expr, e : Expr );
 	EBreak;
 	EContinue;
-	EFunction( args : Array<{ name : String, t : Null<CType> }>, e : Expr, ?name : String, ?ret : CType );
+	EFunction( args : Array<Argument>, e : Expr, ?name : String, ?ret : CType );
 	EReturn( ?e : Expr );
 	EArray( e : Expr, index : Expr );
 	EArrayDecl( e : Array<Expr> );
@@ -69,6 +69,8 @@ enum Expr {
 	ESwitch( e : Expr, cases : Array<{ values : Array<Expr>, expr : Expr }>, ?defaultExpr : Expr);
 }
 
+typedef Argument = { name : String, ?t : CType, ?opt : Bool };
+
 enum CType {
 	CTPath( path : Array<String>, ?params : Array<CType> );
 	CTFun( args : Array<CType>, ret : CType );
diff --git a/hscript/Interp.hx b/hscript/Interp.hx
index efaf654..d14f12d 100644
--- a/hscript/Interp.hx
+++ b/hscript/Interp.hx
@@ -345,8 +345,34 @@ class Interp {
 		case EFunction(params,fexpr,name,_):
 			var capturedLocals = duplicate(locals);
 			var me = this;
+			var hasOpt = false, minParams = 0;
+			for( p in params )
+				if( p.opt )
+					hasOpt = true;
+				else
+					minParams++;
 			var f = function(args:Array<Dynamic>) {
-				if( args.length != params.length ) throw "Invalid number of parameters";
+				if( args.length != params.length ) {
+					if( args.length < minParams ) {
+						var str = "Invalid number of parameters. Got " + args.length + ", required " + minParams;
+						if( name != null ) str += " for function '" + name+"'";
+						throw str;
+					}
+					// make sure mandatory args are forced
+					var args2 = [];
+					var extraParams = args.length - minParams;
+					var pos = 0;
+					for( p in params )
+						if( p.opt ) {
+							if( extraParams > 0 ) {
+								args2.push(args[pos++]);
+								extraParams--;
+							} else
+								args2.push(null);
+						} else
+							args2.push(args[pos++]);
+					args = args2;
+				}
 				var old = me.locals;
 				me.locals = me.duplicate(capturedLocals);
 				for( i in 0...params.length )
diff --git a/hscript/Parser.hx b/hscript/Parser.hx
index 1cb6472..4eade93 100644
--- a/hscript/Parser.hx
+++ b/hscript/Parser.hx
@@ -469,25 +469,32 @@ class Parser {
 			var args = new Array();
 			tk = token();
 			if( tk != TPClose ) {
-				var arg = true;
-				while( arg ) {
-					var name = null;
+				var done = false;
+				while( !done ) {
+					var name = null, opt = false;
+					switch( tk ) {
+					case TQuestion:
+						opt = true;
+						tk = token();
+					default:
+					}
 					switch( tk ) {
 					case TId(id): name = id;
 					default: unexpected(tk);
 					}
 					tk = token();
-					var t = null;
+					var arg : Argument = { name : name };
+					args.push(arg);
+					if( opt ) arg.opt = true;
 					if( tk == TDoubleDot && allowTypes ) {
-						t = parseType();
+						arg.t = parseType();
 						tk = token();
 					}
-					args.push( { name : name, t : t } );
 					switch( tk ) {
 					case TComma:
 						tk = token();
 					case TPClose:
-						arg = false;
+						done = true;
 					default:
 						unexpected(tk);
 					}