muesli/cmd/muesli/main.go

package main

import (
	"fmt"
	"os"
    "io"
    "sort"
	"path/filepath"
    "unicode"
)

import "gitlab.com/beoran/muesli"
import "github.com/peterh/liner"

func runLine(vm *muesli.VM, in string) error {	
	parser := muesli.NewParserFromString(in)
    if val := vm.Lookup("__muesli_debug__"); val == muesli.TrueValue { 
        parser.SetVmLogger(vm)
	}
    kw := vm.LoadKeywords() 
	if kw != nil {
		parser.AddKeywords(kw)
	} else {
		parser.AddKeywords(muesli.DefaultKeywords)
		vm.StoreKeywords(muesli.DefaultKeywords)
	}
	ast := parser.Parse()
	err := ast.ToError()
	if err != nil {
		return err
	}
	result := vm.RunAst(*ast, muesli.NewListValue())
	if result != nil { 
		for _, val := range result { 
			if val != nil { 
				fmt.Printf(">>%s\n", val.String())
			} else {
				fmt.Printf(">>nil\n")
			}
		}
	}
		
	return nil
}

func runLines(vm *muesli.VM, line *liner.State) error {
	for { 	
		if in, err := line.Prompt("> "); err == nil {
			err = runLine(vm, in)
			if err != nil { 
				vm.Errorf("Error %s: \n", err)
			}
			line.AppendHistory(in)
		} else if err == liner.ErrPromptAborted {
			vm.Errorf("Aborted\n")
			return nil
		} else if err == io.EOF { 
            return nil
        } else {
			vm.Errorf("Error reading line: %s\n", err)
		}
	}
	return nil
}

func runFile(vm *muesli.VM, name string) error {
	parser, err := muesli.NewParserFromFilename(name)
	if err != nil {
        vm.Errorf("Error opening file %s: %s\n", name, err)
		return err
	}
	ast := parser.Parse()
	err = ast.ToError()
    if err == io.EOF { 
        return nil
    } else if err != nil {
        vm.Errorf("Error opening file %s: %s\n", name, err)
		return err
	}
	vm.RunAst(*ast, muesli.NewListValue())
	return nil
}

func main() {	
	vm := muesli.NewVM()
	// defer func () { os.Exit(vm.ExitStatus) }()
	// vm.Tracer = &muesli.FmtTracer{}
	vm.RegisterBuiltins() 
	line := liner.NewLiner()
	defer line.Close()

	line.SetCtrlCAborts(true)
	home, _ := os.UserHomeDir()	
	historyName := filepath.Join(home, ".muesli_history")


	if f, err := os.Open(historyName); err == nil {
		line.ReadHistory(f)
		f.Close()
	} 
	
	if len(os.Args) > 1 {
		for _, name := range os.Args {
			err := runFile(vm, name)
			if err != nil {
				return
			}
		}
        return 
	}

	line.SetWordCompleter(func(line string, pos int) (head string, c []string, tail string) {
        end := pos 
        // XXX unicode support!
        for end < len(line) && unicode.IsLetter(rune(line[end])) {
            end++
        }
        if end > len(line) {
            end = len(line)
        } 
        tail = line[end:]
        start := pos - 1
        for start > 0 && unicode.IsLetter(rune(line[start-1])) {
            start--
        }
        if start < 0 {
            start = 0
        }
        fmt.Printf("%d %d %d\n", start, end, len(line))
        
        head = line[0:start]
        word := line[start:end]
        fmt.Printf(">%s<\n", word)
        c = vm.DefinedNamesLike(word)
        sort.Strings(c)
        return head, c, tail
	})


	
	runLines(vm, line)
	
	if f, err := os.Create(historyName); err != nil {
		vm.Errorf("Error writing history file: %s\n", err)
	} else {
		line.WriteHistory(f)
		f.Close()
	}
}