Added running from files

examples/fibonacci.km

@@ -0,0 +1,22 @@
+let fib = fn(x) {
+    if (x == 0) {
+        return 0;
+    }
+
+    if (x == 1) {
+        return 1;
+    }
+
+    return fib(x-1) + fib(x-2);
+};
+
+let main = fn() {
+    let fibTest = fib(10);
+    if (fibTest != 55) {
+        return false;
+    } else {
+        return true;
+    }
+};
+
+main();

main.go

@@ -1,4 +1,4 @@
-package main
+/*package main
 
 import (
 	"fmt"
@@ -18,3 +18,96 @@ func main() {
 	fmt.Printf("Feel free to type commands!\n")
 	repl.Start(os.Stdin, os.Stdout)
 }
+*/
+package main
+
+import (
+	"fmt"
+	"io"
+	"io/ioutil"
+	"os"
+
+	"github.com/kscarlett/kmonkey/evaluator"
+	"github.com/kscarlett/kmonkey/lexer"
+	"github.com/kscarlett/kmonkey/object"
+	"github.com/kscarlett/kmonkey/parser"
+	"github.com/kscarlett/kmonkey/repl"
+
+	log "github.com/sirupsen/logrus"
+	"github.com/ttacon/chalk"
+	"gopkg.in/alecthomas/kingpin.v2"
+)
+
+var (
+	app     = kingpin.New("kmonkey", "The kmonkey interpreter")
+	verbose = app.Flag("verbose", "Enable verbose logging.").Short('v').Bool()
+
+	interactive = app.Command("interactive", "Interactive REPL")
+
+	run     = app.Command("run", "Run kmonkey code")
+	runFile = run.Flag("file", "Code to run").Required().Short('f').ExistingFile()
+)
+
+func init() {
+	log.SetFormatter(&log.TextFormatter{FullTimestamp: true})
+	log.SetOutput(os.Stdout)
+}
+
+func main() {
+	app.Version("0.1.0")
+	args, err := app.Parse(os.Args[1:])
+
+	if *verbose {
+		log.SetLevel(log.DebugLevel)
+	} else {
+		log.SetLevel(log.WarnLevel)
+	}
+
+	switch kingpin.MustParse(args, err) {
+	case run.FullCommand():
+		log.WithFields(log.Fields{
+			"File":    *runFile,
+			"Verbose": *verbose,
+		}).Debug("Received run command")
+
+		runFromFile()
+	case interactive.FullCommand():
+		startRepl()
+	}
+}
+
+func runFromFile() {
+	file, err := ioutil.ReadFile(*runFile)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	l := lexer.New(string(file))
+	p := parser.New(l)
+	program := p.ParseProgram()
+
+	if len(p.Errors()) != 0 {
+		printParserErrors(os.Stdout, p.Errors())
+		os.Exit(21)
+	}
+
+	env := object.NewEnvironment()
+	eval := evaluator.Eval(program, env)
+	if eval.Inspect() != "NULL" {
+		fmt.Println(eval.Inspect())
+	}
+}
+
+func startRepl() {
+	fmt.Printf("Starting kmonkey interactive interpreter v%s\n", "0.2.0") // Find a way to get this from app.version
+	repl.Start(os.Stdin, os.Stdout)
+}
+
+func printParserErrors(out io.Writer, errors []string) {
+	errColor := chalk.Red.NewStyle().WithTextStyle(chalk.Bold).Style
+
+	io.WriteString(out, errColor("PARSER ERROR!\n"))
+	for _, msg := range errors {
+		io.WriteString(out, errColor("  [!] ")+msg+"\n")
+	}
+}