create binary

Author: Dean Karn

README.md

@@ -11,7 +11,7 @@ ksql
 
 #### How to install CLI
 ```shell
-~ go install github.com/go-playground/ksql
+~ go install github.com/go-playground/ksql/cmd/ksql
 ```
 
 #### Usage

cmd/ksql/main.go

@@ -0,0 +1,54 @@
+package main
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+
+	"github.com/go-playground/ksql"
+)
+
+func main() {
+	args := os.Args[1:]
+	isPipe := isInputFromPipe()
+	if (len(args) < 2 && !isPipe) || (len(args) < 1 && isPipe) {
+		usage()
+		return
+	}
+
+	ex, err := ksql.Parse([]byte(args[0]))
+	if err != nil {
+		usage()
+		return
+	}
+
+	var input []byte
+
+	if isPipe {
+		input, err = ioutil.ReadAll(os.Stdin)
+		if err != nil {
+			usage()
+			return
+		}
+	} else {
+		input = []byte(args[1])
+	}
+
+	result, err := ex.Calculate(input)
+	if err != nil {
+		usage()
+		return
+	}
+	fmt.Println(result)
+}
+
+func usage() {
+	fmt.Println("ksql <expression> <json>")
+	fmt.Println("or")
+	fmt.Println("echo '{{}}' | ksql <expression> -")
+}
+
+func isInputFromPipe() bool {
+	fileInfo, _ := os.Stdin.Stat()
+	return fileInfo.Mode()&os.ModeCharDevice == 0
+}