From a9463a180d28e95508a1ce974e8e15825711cbb1 Mon Sep 17 00:00:00 2001
From: Alexander Medvednikov <alexander@medvednikov.com>
Date: Wed, 17 Jul 2019 01:43:59 +0200
Subject: [PATCH] new match statement

---
 compiler/parser.v           | 23 ++++++++++++++++-------
 compiler/scanner.v          |  4 ++++
 compiler/tests/match_test.v | 11 +++++++++++
 compiler/token.v            |  5 ++++-
 4 files changed, 35 insertions(+), 8 deletions(-)
 create mode 100644 compiler/tests/match_test.v

diff --git a/compiler/parser.v b/compiler/parser.v
index ea74aed482..b3647c2b00 100644
--- a/compiler/parser.v
+++ b/compiler/parser.v
@@ -946,7 +946,7 @@ fn (p mut Parser) statements_no_curly_end() string {
 	mut i := 0
 	mut last_st_typ := ''
 	for p.tok != .rcbr && p.tok != .eof && p.tok != .key_case && 
-		p.tok != .key_default {
+		p.tok != .key_default && p.peek() != .arrow {
 		// println(p.tok.str())
 		// p.print_tok()
 		last_st_typ = p.statement(true)
@@ -961,7 +961,7 @@ fn (p mut Parser) statements_no_curly_end() string {
 			p.error('more than 50 000 statements in function `$p.cur_fn.name`')
 		}
 	}
-	if p.tok != .key_case && p.tok != .key_default {
+	if p.tok != .key_case && p.tok != .key_default && p.peek() != .arrow {
 		// p.next()
 		p.check(.rcbr)
 	}
@@ -1044,7 +1044,7 @@ fn (p mut Parser) statement(add_semi bool) string {
 		p.if_st(false, 0)
 	case Token.key_for:
 		p.for_st()
-	case Token.key_switch: 
+	case Token.key_switch, Token.key_match: 
 		p.switch_statement()
 	case Token.key_mut, Token.key_static:
 		p.var_decl()
@@ -3031,14 +3031,18 @@ fn (p mut Parser) for_st() {
 }
 
 fn (p mut Parser) switch_statement() {
-	p.check(.key_switch) 
+	if p.tok == .key_switch { 
+		p.check(.key_switch) 
+	} else {
+		p.check(.key_match) 
+	} 
 	p.cgen.start_tmp()
 	typ := p.bool_expression()
 	expr := p.cgen.end_tmp()
 	p.check(.lcbr)
 	mut i := 0
-	for p.tok == .key_case || p.tok == .key_default { 
-		if p.tok == .key_default { 
+	for p.tok == .key_case || p.tok == .key_default || p.peek() == .arrow || p.tok == .key_else { 
+		if p.tok == .key_default || p.tok == .key_else { 
 			p.genln('else  { // default:')
 			p.check(.key_default) 
 			p.check(.colon)
@@ -3071,7 +3075,12 @@ fn (p mut Parser) switch_statement() {
 			p.check(.comma)
 			got_comma = true
 		}
-		p.check(.colon)
+		if p.tok == .colon { 
+			p.check(.colon)
+		} 
+		else { 
+			p.check(.arrow) 
+		} 
 		p.gen(')) {')
 		p.genln('/* case */')
 		p.statements()
diff --git a/compiler/scanner.v b/compiler/scanner.v
index 8426cd0cb5..1dd2b64bcd 100644
--- a/compiler/scanner.v
+++ b/compiler/scanner.v
@@ -430,6 +430,10 @@ fn (s mut Scanner) scan() ScanRes {
 			s.pos++
 			return scan_res(.eq, '')
 		}
+		else if nextc == `>` {
+			s.pos++
+			return scan_res(.arrow, '')
+		} 
 		else {
 			return scan_res(.assign, '')
 		}
diff --git a/compiler/tests/match_test.v b/compiler/tests/match_test.v
new file mode 100644
index 0000000000..d873f587f9
--- /dev/null
+++ b/compiler/tests/match_test.v
@@ -0,0 +1,11 @@
+fn test_switch() {
+	a := 3 
+	mut b := 0 
+	match a {
+	2 => println('two') 
+	3 => println('three') 
+	     b = 3 
+	4 => println('4') 
+	} 
+	assert b == 3 
+} 
diff --git a/compiler/token.v b/compiler/token.v
index 309540f806..f68b409af0 100644
--- a/compiler/token.v
+++ b/compiler/token.v
@@ -27,6 +27,7 @@ enum Token {
 	comma
 	semicolon
 	colon
+	arrow // => 
 	amp
 	hash
 	dollar
@@ -90,7 +91,7 @@ enum Token {
 	key_import_const 
 	key_in 
 	key_interface 
-	MATCH
+	key_match 
 	key_module
 	key_mut
 	key_return
@@ -148,6 +149,7 @@ fn build_token_str() []string {
 	s[Token.comma] = ','
 	s[Token.semicolon] = ';'
 	s[Token.colon] = ':'
+	s[Token.arrow] = '=>'
 	s[Token.assign] = '='
 	s[Token.decl_assign] = ':='
 	s[Token.plus_assign] = '+='
@@ -215,6 +217,7 @@ fn build_token_str() []string {
 	s[Token.key_static] = 'static'
 	s[Token.key_as] = 'as'
 	s[Token.key_defer] = 'defer'
+	s[Token.key_match] = 'match'
 	return s
 }