started work on porting it to golang

go/main.go

@@ -0,0 +1,93 @@
+package main
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/chzyer/readline"
+	flag "github.com/spf13/pflag"
+)
+
+const VERSION string = "0.0.1"
+
+const Usage string = `This is rpn, a reverse polish notation calculator cli.
+
+Usage: rpn [-bdvh] [<operator>]
+
+Options:
+  -b, --batchmode   enable batch mode
+  -d, --debug       enable debug mode
+  -v, --version     show version
+  -h, --help        show help
+
+When <operator>  is given, batch  mode ist automatically  enabled. Use
+this only when working with stdin. E.g.: echo "2 3 4 5" | rpn +
+
+Copyright (c) 2023 T.v.Dein
+`
+
+func main() {
+	calc := NewCalc()
+
+	showversion := false
+	showhelp := false
+	enabledebug := false
+
+	flag.BoolVarP(&calc.batch, "batchmode", "b", false, "batch mode")
+	flag.BoolVarP(&enabledebug, "debug", "d", false, "debug mode")
+	flag.BoolVarP(&showversion, "version", "v", false, "show version")
+	flag.BoolVarP(&showhelp, "help", "h", false, "show usage")
+	flag.Parse()
+
+	if showversion {
+		fmt.Printf("This is rpn version %s\n", VERSION)
+		return
+	}
+
+	if showhelp {
+		fmt.Println(Usage)
+		return
+	}
+
+	if enabledebug {
+		calc.ToggleDebug()
+	}
+
+	rl, err := readline.NewEx(&readline.Config{
+		Prompt:            "\033[31m»\033[0m ",
+		HistoryFile:       os.Getenv("HOME") + ".rpn-history",
+		HistoryLimit:      500,
+		AutoComplete:      calc.completer,
+		InterruptPrompt:   "^C",
+		EOFPrompt:         "exit",
+		HistorySearchFold: true,
+	})
+
+	if err != nil {
+		panic(err)
+	}
+	defer rl.Close()
+	rl.CaptureExitSignal()
+
+	if inputIsStdin() {
+		calc.ToggleStdin()
+	}
+
+	for {
+		line, err := rl.Readline()
+		if err != nil {
+			break
+		}
+
+		calc.Eval(line)
+	}
+
+	if len(flag.Args()) > 0 {
+		calc.Eval(flag.Args()[0])
+	}
+}
+
+func inputIsStdin() bool {
+	stat, _ := os.Stdin.Stat()
+	return (stat.Mode() & os.ModeCharDevice) == 0
+}