deprecate perl version, make go version the new one (2.0.0)

main.go

@@ -0,0 +1,143 @@
+/*
+Copyright © 2023 Thomas von Dein
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program. If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package main
+
+import (
+	"fmt"
+	"os"
+	"strings"
+
+	"github.com/chzyer/readline"
+	flag "github.com/spf13/pflag"
+	lua "github.com/yuin/gopher-lua"
+)
+
+const VERSION string = "2.0.0"
+
+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
+	configfile := ""
+
+	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.StringVarP(&configfile, "config", "c",
+		os.Getenv("HOME")+"/.rpn.lua", "config file (lua format)")
+
+	flag.Parse()
+
+	if showversion {
+		fmt.Printf("This is rpn version %s\n", VERSION)
+		return
+	}
+
+	if showhelp {
+		fmt.Println(Usage)
+		return
+	}
+
+	if enabledebug {
+		calc.ToggleDebug()
+	}
+
+	// the lua state object is global, instanciate it early
+	L = lua.NewState(lua.Options{SkipOpenLibs: true})
+	defer L.Close()
+
+	// our config file is interpreted  as lua code, only functions can
+	// be defined, init() will be called by InitLua().
+	if _, err := os.Stat(configfile); err == nil {
+		I := InitLua(configfile, enabledebug)
+		calc.SetInt(I)
+	}
+
+	if len(flag.Args()) > 1 {
+		// commandline calc operation, no readline etc needed
+		// called like rpn 2 2 +
+		calc.stdin = true
+		calc.Eval(strings.Join(flag.Args(), " "))
+		return
+	}
+
+	// interactive mode, need readline
+	rl, err := readline.NewEx(&readline.Config{
+		Prompt:            calc.Prompt(),
+		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() {
+		// commands are  coming on stdin, however we  will still enter
+		// the same loop since readline just reads fine from stdin
+		calc.ToggleStdin()
+	}
+
+	for {
+		// primary program repl
+		line, err := rl.Readline()
+		if err != nil {
+			break
+		}
+
+		calc.Eval(line)
+		rl.SetPrompt(calc.Prompt())
+	}
+
+	if len(flag.Args()) > 0 {
+		// called like this:
+		// echo 1 2 3 4 | rpn +
+		// batch mode enabled automatically
+		calc.batch = true
+		calc.Eval(flag.Args()[0])
+	}
+}
+
+func inputIsStdin() bool {
+	stat, _ := os.Stdin.Stat()
+	return (stat.Mode() & os.ModeCharDevice) == 0
+}