From 3b94999e55df35d19616e87d7f3b6fddf5b8a30b Mon Sep 17 00:00:00 2001
From: Li Jin <dragon-fly@qq.com>
Date: Wed, 26 Feb 2020 11:46:27 +0800
Subject: add fat arrow support for backcall statement.

---
 spec/inputs/backcall.moon   | 13 +++++++++++++
 src/MoonP/moon_ast.h        |  7 ++++++-
 src/MoonP/moon_compiler.cpp |  5 +++--
 src/MoonP/moon_parser.cpp   |  3 ++-
 src/MoonP/moon_parser.h     |  1 +
 src/moonp.cpp               |  2 +-
 6 files changed, 26 insertions(+), 5 deletions(-)

diff --git a/spec/inputs/backcall.moon b/spec/inputs/backcall.moon
index 3aedba9..2972b1d 100644
--- a/spec/inputs/backcall.moon
+++ b/spec/inputs/backcall.moon
@@ -90,4 +90,17 @@ do
 		(data)<- loadAsync file
 		addToCache file,data) |> reduce 0,(a,b)-> a+b
 
+propA = do
+	(value)<= property => @_value
+	print "old value: #{@_value}"
+	print "new value: #{value}"
+	@_value = value
+
+propB = do
+	<= property _, (value)=>
+		print "old value: #{@_value}"
+		print "new value: #{value}"
+		@_value = value
+	@_value
+
 alert "hi"
diff --git a/src/MoonP/moon_ast.h b/src/MoonP/moon_ast.h
index 917429e..dd01165 100644
--- a/src/MoonP/moon_ast.h
+++ b/src/MoonP/moon_ast.h
@@ -135,12 +135,17 @@ AST_NODE(Import)
 AST_END(Import)
 
 class FnArgsDef_t;
+
+AST_LEAF(fn_arrow_back)
+AST_END(fn_arrow_back)
+
 class ChainValue_t;
 
 AST_NODE(Backcall)
 	ast_ptr<false, FnArgsDef_t> argsDef;
+	ast_ptr<true, fn_arrow_back_t> arrow;
 	ast_ptr<true, ChainValue_t> value;
-	AST_MEMBER(Backcall, &argsDef, &value)
+	AST_MEMBER(Backcall, &argsDef, &arrow, &value)
 AST_END(Backcall)
 
 AST_NODE(ExpListLow)
diff --git a/src/MoonP/moon_compiler.cpp b/src/MoonP/moon_compiler.cpp
index a39bfd0..83b91e6 100644
--- a/src/MoonP/moon_compiler.cpp
+++ b/src/MoonP/moon_compiler.cpp
@@ -32,7 +32,7 @@ inline std::string s(std::string_view sv) {
 }
 
 const char* moonScriptVersion() {
-	return "0.5.0-r0.1.4";
+	return "0.5.0-r0.1.5";
 }
 
 class MoonCompilerImpl {
@@ -1740,7 +1740,8 @@ private:
 					body->content.set(block);
 					auto funLit = x->new_ptr<FunLit_t>();
 					funLit->argsDef.set(backcall->argsDef);
-					funLit->arrow.set(toAst<fn_arrow_t>("->"sv, x));
+					auto arrow = _parser.toString(backcall->arrow);
+					funLit->arrow.set(toAst<fn_arrow_t>(arrow == "<-"sv ? "->"sv : "=>"sv, x));
 					funLit->body.set(body);
 					auto simpleValue = x->new_ptr<SimpleValue_t>();
 					simpleValue->value.set(funLit);
diff --git a/src/MoonP/moon_parser.cpp b/src/MoonP/moon_parser.cpp
index 1502f3c..fecf869 100644
--- a/src/MoonP/moon_parser.cpp
+++ b/src/MoonP/moon_parser.cpp
@@ -434,7 +434,8 @@ MoonParser::MoonParser() {
 	NameOrDestructure = Space >> Variable | TableLit;
 	AssignableNameList = Seperator >> NameOrDestructure >> *(sym(',') >> White >> NameOrDestructure);
 
-	Backcall = -FnArgsDef >> Space >> symx("<-") >> Space >> ChainValue;
+	fn_arrow_back = expr('<') >> set("-=");
+	Backcall = -FnArgsDef >> Space >> fn_arrow_back >> Space >> ChainValue;
 
 	ExpList = Seperator >> Exp >> *(sym(',') >> White >> Exp);
 	ExpListLow = Seperator >> Exp >> *((sym(',') | sym(';')) >> White >> Exp);
diff --git a/src/MoonP/moon_parser.h b/src/MoonP/moon_parser.h
index 215c6a4..12f735b 100644
--- a/src/MoonP/moon_parser.h
+++ b/src/MoonP/moon_parser.h
@@ -191,6 +191,7 @@ private:
 	AST_RULE(ImportFrom)
 	AST_RULE(ImportAs)
 	AST_RULE(Import)
+	AST_RULE(fn_arrow_back)
 	AST_RULE(Backcall)
 	AST_RULE(ExpListLow)
 	AST_RULE(ExpList)
diff --git a/src/moonp.cpp b/src/moonp.cpp
index 3f36d9d..ade1a1b 100644
--- a/src/moonp.cpp
+++ b/src/moonp.cpp
@@ -247,7 +247,7 @@ static int moontolua(lua_State* L) {
 	} else {
 		lua_pushlstring(L, err.c_str(), err.size());
 	}
-	if (globals && !globals->empty()) {
+	if (globals) {
 		lua_createtable(L, static_cast<int>(globals->size()), 0);
 		int i = 1;
 		for (const auto& var : *globals) {
-- 
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