From 9357758697305753a68b541b42452a8cb13eebe2 Mon Sep 17 00:00:00 2001
From: Ryo Nihei <nihei.dev@gmail.com>
Date: Sat, 20 Feb 2021 17:36:16 +0900
Subject: Add + and ? operators

* a+ matches 'a' one or more times. This is equivalent to aa*.
* a? matches 'a' zero or one time.
---
 compiler/parser.go | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

(limited to 'compiler/parser.go')

diff --git a/compiler/parser.go b/compiler/parser.go
index ede601d..04cd8ad 100644
--- a/compiler/parser.go
+++ b/compiler/parser.go
@@ -144,10 +144,16 @@ func (p *parser) parseConcat() astNode {
 
 func (p *parser) parseRepeat() astNode {
 	group := p.parseGroup()
-	if !p.consume(tokenKindRepeat) {
-		return group
+	if p.consume(tokenKindRepeat) {
+		return newRepeatNode(group)
 	}
-	return newRepeatNode(group)
+	if p.consume(tokenKindRepeatOneOrMore) {
+		return newRepeatOneOrMoreNode(group)
+	}
+	if p.consume(tokenKindOption) {
+		return newOptionNode(group)
+	}
+	return group
 }
 
 func (p *parser) parseGroup() astNode {
-- 
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