Add dot feature

README.md

@@ -45,15 +45,15 @@ $ echo '{"key":"value"}' | xx
 You can get access to JSON by `this` keyword:
 ```
 $ echo '{"foo": [{"bar": "value"}]}' | xx 'this.foo[0].bar'
-"value"
+value
 ```
 
 ### Chain
 
 You can pass any number of code blocks for reducing JSON:
 ```
 $ echo '{"foo": [{"bar": "value"}]}' | xx 'this.foo' 'this[0]' 'this.bar'
-"value"
+value
 ```
 
 ### Formatting
@@ -99,6 +99,15 @@ By the way, xx has shortcut for `Object.keys(this)`. Previous example can be rew
 $ echo '{"foo": 1, "bar": 2}' | xx ?
 ``` 
 
+### Dot
+
+It is possible to omit `this` keyword:
+
+```
+$ echo '{"foo": "bar"}' | xx .foo[0].bar
+value
+```
+
 ## Related
 
 * [fx](https://github.com/antonmedv/fx) – original `fx` package

main.go

@@ -51,6 +51,11 @@ func main() {
 		return
 	}
 
+	if value.IsString() {
+		fmt.Println(value)
+		return
+	}
+
 	i, err := value.Export()
 	if err != nil {
 		fatal(err)
@@ -66,9 +71,13 @@ func reduce(value otto.Value, code string) (otto.Value, error) {
 	if err := vm.Set("json", value); err != nil {
 		fatal(err)
 	}
-	switch code {
-	case "?":
+	switch {
+	case code == "?":
 		code = "Object.keys(json)"
+	case code == ".":
+		code = "(function () {return this;}).call(json)"
+	case len(code) > 1 && code[0] == '.':
+		code = fmt.Sprintf(`(function () {return this%v;}).call(json)`, code)
 	default:
 		code = fmt.Sprintf(`(function () {return %v;}).call(json)`, code)
 	}
@@ -81,6 +90,8 @@ func reduce(value otto.Value, code string) (otto.Value, error) {
 
 func usage() {
 	fmt.Fprintf(os.Stderr, `
+  Command-line JSON processing tool
+
   Usage
     $ xx [code ...]
 
@@ -94,6 +105,12 @@ func usage() {
     $ echo '{"items": ["one", "two"]}' | xx 'this.items' 'this[1]'
     "two"
 
+    $ echo '{"foo": 1, "bar": 2}' | xx ?
+    ["foo", "bar"]
+    
+    $ echo '{"key": "value"}' | xx .key
+    value
+
 `)
 }