From 6e1c004fea8d841f554c2e94ff39e1fcee94b4e3 Mon Sep 17 00:00:00 2001
From: Adam Scarr <adam@vektah.net>
Date: Mon, 7 Aug 2017 22:57:06 +1000
Subject: [PATCH] Add Bind for constants

---
 combinator.go | 13 +++++++++++++
 json/json.go  | 20 ++++----------------
 2 files changed, 17 insertions(+), 16 deletions(-)

diff --git a/combinator.go b/combinator.go
index f072913..e83a0c1 100644
--- a/combinator.go
+++ b/combinator.go
@@ -123,6 +123,19 @@ func Maybe(parser Parserish) Parser {
 	})
 }
 
+func Bind(parser Parserish, val interface{}) Parser {
+	p := Parsify(parser)
+
+	return func(ps *State) Node {
+		node := p(ps)
+		if ps.Errored() {
+			return node
+		}
+		node.Result = val
+		return node
+	}
+}
+
 func Map(parser Parserish, f func(n Node) Node) Parser {
 	p := Parsify(parser)
 
diff --git a/json/json.go b/json/json.go
index 28889bd..13db8a5 100644
--- a/json/json.go
+++ b/json/json.go
@@ -27,25 +27,13 @@ var (
 		return Node{Result: ret}
 	})
 
-	_null = Map("null", func(n Node) Node {
-		return Node{Result: nil}
-	})
-
-	_true = Map("true", func(n Node) Node {
-		return Node{Result: true}
-	})
-
-	_false = Map("false", func(n Node) Node {
-		return Node{Result: false}
-	})
+	_null  = Bind("null", nil)
+	_true  = Bind("true", true)
+	_false = Bind("false", false)
 
 	_string = Map(String('"'), func(n Node) Node {
 		return Node{Result: n.Token}
 	})
-
-	Y = Map(&value, func(n Node) Node {
-		return Node{Result: n.Result}
-	})
 )
 
 func init() {
@@ -53,7 +41,7 @@ func init() {
 }
 
 func Unmarshal(input string) (interface{}, error) {
-	result, remaining, err := ParseString(Y, input)
+	result, remaining, err := ParseString(value, input)
 
 	if err != nil {
 		return result, err