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//
// Copyright (c) 2018, Přemysl Janouch <p@janouch.name>
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted.
//
// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
// SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
// OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
// CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
//
// Program repl is an interactive ell interpreter.
package main
import (
"fmt"
"io"
"os"
"strings"
// This library is rather simplistic but it's going to serve us fine.
"github.com/peterh/liner"
"janouch.name/ell/ell"
)
func run(L *ell.Ell, program *ell.V) {
var result *ell.V
if !L.EvalBlock(program, nil, &result) {
fmt.Printf("\x1b[31m%s: %s\x1b[0m\n", "runtime error", L.Error)
L.Error = ""
} else {
ell.PrintSeq(os.Stdout, result)
os.Stdout.WriteString("\n")
}
}
func complete(L *ell.Ell, line string) (res []string) {
// This never actually completes anything, just shows the options,
// we'd have to figure out the longest common prefix.
res = append(res, line)
line = strings.ToLower(line)
for v := L.Globals; v != nil; v = v.Next {
name := string(v.Head.String)
if strings.HasPrefix(strings.ToLower(name), line) {
res = append(res, name)
}
}
for name := range L.Native {
if strings.HasPrefix(strings.ToLower(name), line) {
res = append(res, name)
}
}
return
}
func main() {
L := ell.New()
if !ell.StdInitialize(L) {
fmt.Printf("runtime library initialization failed: %s\n", L.Error)
}
line := liner.NewLiner()
line.SetCompleter(func(line string) []string { return complete(L, line) })
line.SetMultiLineMode(true)
line.SetTabCompletionStyle(liner.TabPrints)
for {
script, err := line.Prompt("> ")
if err == nil {
line.AppendHistory(script)
p := ell.NewParser([]byte(script))
if program, err := p.Run(); err != nil {
fmt.Printf("\x1b[31m%s: %s\x1b[0m\n", "parse error", err)
} else {
run(L, program)
}
} else if err == liner.ErrPromptAborted || err == io.EOF {
break
} else {
fmt.Printf("\x1b[31m%s: %s\x1b[0m\n", "error", err)
}
}
os.Stdout.WriteString("\n")
}
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