Add a json parser

1 files changed, 68 insertions, 0 deletions

diff --git a/json/json.go b/json/json.go
new file mode 100644
index 0000000..3aa5163
--- /dev/null
+++ b/json/json.go
@@ -0,0 +1,68 @@
+package json
+
+import (
+	"errors"
+
+	. "github.com/vektah/goparsify"
+)
+
+var (
+	value Parser
+
+	array = Map(And(WS, "[", Kleene(&value, And(WS, ",")), "]"), func(n Node) Node {
+		return n.([]Node)[1].([]Node)
+	})
+	properties = Kleene(And(WS, String('"'), WS, ":", WS, &value), ",")
+	object     = Map(And(WS, "{", WS, properties, WS, "}"), func(n Node) Node {
+		ret := map[string]interface{}{}
+
+		for _, prop := range n.([]Node)[1].([]Node) {
+			vals := prop.([]Node)
+			if len(vals) == 3 {
+				ret[vals[0].(string)] = vals[2]
+			} else {
+				ret[vals[0].(string)] = nil
+			}
+		}
+
+		return ret
+	})
+
+	_null = Map(And(WS, "null"), func(n Node) Node {
+		return nil
+	})
+
+	_true = Map(And(WS, "true"), func(n Node) Node {
+		return true
+	})
+
+	_false = Map(And(WS, "false"), func(n Node) Node {
+		return false
+	})
+
+	Y = Map(And(&value, WS), func(n Node) Node {
+		nodes := n.([]Node)
+		if len(nodes) > 0 {
+			return nodes[0]
+		}
+		return nil
+	})
+)
+
+func init() {
+	value = Any(_null, _true, _false, String('"'), array, object)
+}
+
+func Unmarshal(input string) (interface{}, error) {
+	result, remaining, err := ParseString(Y, input)
+
+	if err != nil {
+		return result, err
+	}
+
+	if remaining != "" {
+		return result, errors.New("left unparsed: " + remaining)
+	}
+
+	return result, err
+}