From 521e6da1f6c9c964abca5bac22ce62823c276c1f Mon Sep 17 00:00:00 2001
From: Alexander Kiryukhin <a.kiryukhin@mail.ru>
Date: Sun, 7 Mar 2021 23:44:10 +0300
Subject: [PATCH] Added JSON example

---
 example/json/main.go | 99 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 99 insertions(+)
 create mode 100644 example/json/main.go

diff --git a/example/json/main.go b/example/json/main.go
new file mode 100644
index 0000000..842ab82
--- /dev/null
+++ b/example/json/main.go
@@ -0,0 +1,99 @@
+// +build ignore
+
+package main
+
+import (
+	"fmt"
+
+	"github.com/neonxp/unilex"
+)
+
+func main() {
+	testJson := `
+	{
+		"key1": "value1",
+		"key2": {
+			"key3" : "value 3"
+		},
+		"key4": 123.321
+	}`
+	l := unilex.New(testJson)
+	go l.Run(initJson)
+	for ll := range l.Output {
+		fmt.Println(ll)
+	}
+}
+
+const (
+	lObjectStart       unilex.LexType = "lObjectStart"
+	lObjectEnd         unilex.LexType = "lObjectEnd"
+	lObjectKey         unilex.LexType = "lObjectKey"
+	lObjectValueString unilex.LexType = "lObjectValueString"
+	lObjectValueNumber unilex.LexType = "lObjectValueNumber"
+)
+
+func initJson(l *unilex.Lexer) unilex.StateFunc {
+	ignoreWhiteSpace(l)
+	switch {
+	case l.Accept("{"):
+		l.Emit(lObjectStart)
+		return stateInObject(true)
+	case l.Peek() == unilex.EOF:
+		return nil
+	}
+	return l.Errorf("Unknown token: %s", l.Peek())
+}
+
+func stateInObject(initial bool) unilex.StateFunc {
+	return func(l *unilex.Lexer) unilex.StateFunc {
+		// we in object, so we expect field keys and values
+		ignoreWhiteSpace(l)
+		if l.Accept("}") {
+			l.Emit(lObjectEnd)
+			if initial {
+				return initJson
+			}
+			ignoreWhiteSpace(l)
+			l.Accept(",")
+			ignoreWhiteSpace(l)
+			return stateInObject(initial)
+		}
+		if l.Peek() == unilex.EOF {
+			return nil
+		}
+		if !unilex.ScanQuotedString(l, '"') {
+			return l.Errorf("Unknown token: %s", l.Peek())
+		}
+		l.Emit(lObjectKey)
+		ignoreWhiteSpace(l)
+		if !l.Accept(":") {
+			return l.Errorf("Expected ':'")
+		}
+		ignoreWhiteSpace(l)
+		switch {
+		case unilex.ScanQuotedString(l, '"'):
+			l.Emit(lObjectValueString)
+			ignoreWhiteSpace(l)
+			l.Accept(",")
+			l.Ignore()
+			ignoreWhiteSpace(l)
+			return stateInObject(initial)
+		case unilex.ScanNumber(l):
+			l.Emit(lObjectValueNumber)
+			ignoreWhiteSpace(l)
+			l.Accept(",")
+			l.Ignore()
+			ignoreWhiteSpace(l)
+			return stateInObject(initial)
+		case l.Accept("{"):
+			l.Emit(lObjectStart)
+			return stateInObject(false)
+		}
+		return l.Errorf("Unknown token")
+	}
+}
+
+func ignoreWhiteSpace(l *unilex.Lexer) {
+	l.AcceptWhile(" \n\t") //ignore whitespaces
+	l.Ignore()
+}