defer statement

compiler/fn.v

@@ -29,7 +29,7 @@ mut:
 	is_method     bool
 	returns_error bool
 	is_decl       bool // type myfn fn(int, int)
-	defer         string
+	defer_text    string
 }
 
 fn (f &Fn) find_var(name string) Var {
@@ -380,7 +380,7 @@ pthread_create(&_thread_so , NULL, &reload_so, NULL); ')
 	if p.pref.is_prof && f.name != 'main' && f.name != 'time__ticks' {
 		p.genln('double _PROF_START = time__ticks();//$f.name')
 		cgen_name := p.table.cgen_name(f)
-		f.defer = '  ${cgen_name}_time += time__ticks() - _PROF_START;'
+		f.defer_text = '  ${cgen_name}_time += time__ticks() - _PROF_START;'
 	}
 	p.statements_no_curly_end()
 	// Print counting result after all statements in main
@@ -388,7 +388,7 @@ pthread_create(&_thread_so , NULL, &reload_so, NULL); ')
 		p.genln(p.print_prof_counters())
 	}
 	// Counting or not, always need to add defer before the end
-	p.genln(f.defer)
+	p.genln(f.defer_text)
 	if typ != 'void' && !p.returns && f.name != 'main' && f.name != 'WinMain' {
 		p.error('$f.name must return "$typ"')
 	}

compiler/parser.v

@@ -1022,6 +1022,9 @@ fn (p mut Parser) statement(add_semi bool) string {
 		label := p.check_name()
 		p.genln('goto $label;')
 		return ''
+	case Token.key_defer:
+		p.defer_st()
+		return ''
 	case Token.hash:
 		p.chash()
 		return ''
@@ -1038,7 +1041,7 @@ fn (p mut Parser) statement(add_semi bool) string {
 	case Token.key_return:
 		p.return_st()
 	case Token.lcbr:// {} block
-		p.next()
+		p.check(.lcbr) 
 		p.genln('{')
 		p.statements()
 		return ''
@@ -3088,7 +3091,7 @@ else {
 }
 
 fn (p mut Parser) return_st() {
-	p.cgen.insert_before(p.cur_fn.defer)
+	p.cgen.insert_before(p.cur_fn.defer_text)
 	p.check(.key_return)
 
 	fn_returns := p.cur_fn.typ != 'void'
@@ -3265,6 +3268,19 @@ fn (p mut Parser) attribute() {
 	p.error('bad attribute usage') 
 } 
 
+fn (p mut Parser) defer_st() {
+	p.check(.key_defer)
+	// Wrap everything inside the defer block in /**/ comments, and save it in 
+	// `defer_text`. It will be inserted before every `return`. 
+	p.genln('/*') 
+	pos := p.cgen.lines.len 
+	p.check(.lcbr) 
+	p.genln('{') 
+	p.statements() 
+	p.cur_fn.defer_text = p.cgen.lines.right(pos).join('\n') 
+	p.genln('*/') 
+}  
+
 
 ///////////////////////////////////////////////////////////////////////////////
 

compiler/token.v

@@ -75,6 +75,7 @@ enum Token {
 	key_const
 	key_continue
 	key_default 
+	key_defer 
 	key_else
 	key_embed
 	key_enum
@@ -213,6 +214,7 @@ fn build_token_str() []string {
 	s[Token.key_union] = 'union'
 	s[Token.key_static] = 'static'
 	s[Token.key_as] = 'as'
+	s[Token.key_defer] = 'defer'
 	return s
 }