96 lines
2.5 KiB
Go
96 lines
2.5 KiB
Go
//
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// Copyright (c) 2018, Přemysl Eric Janouch <p@janouch.name>
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//
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// Permission to use, copy, modify, and/or distribute this software for any
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// purpose with or without fee is hereby granted.
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//
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// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
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// SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
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// OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
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// CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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//
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// Program repl is an interactive ell interpreter.
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package main
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import (
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"fmt"
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"io"
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"os"
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"strings"
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// This library is rather simplistic but it's going to serve us fine.
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"github.com/peterh/liner"
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"janouch.name/ell/ell"
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)
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func run(L *ell.Ell, program []ell.V) {
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if result, ok := L.EvalBlock(program, nil); !ok {
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fmt.Printf("\x1b[31m%s: %s\x1b[0m\n", "runtime error", L.Error)
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L.Error = ""
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} else {
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ell.PrintSeq(os.Stdout, result)
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os.Stdout.WriteString("\n")
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}
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}
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func complete(L *ell.Ell, line string, pos int) (
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head string, completions []string, tail string) {
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tail = string([]rune(line)[pos:])
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lastSpace := strings.LastIndexAny(string([]rune(line)[:pos]), " ()[]{};\n")
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if lastSpace > -1 {
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head, line = line[:lastSpace+1], line[lastSpace+1:]
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}
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for name := range L.Globals {
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if strings.HasPrefix(strings.ToLower(name), line) {
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completions = append(completions, name)
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}
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}
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for name := range L.Native {
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if strings.HasPrefix(strings.ToLower(name), line) {
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completions = append(completions, name)
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}
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}
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return
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}
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func main() {
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L := ell.New()
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if !ell.StdInitialize(L) {
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fmt.Printf("runtime library initialization failed: %s\n", L.Error)
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}
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line := liner.NewLiner()
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line.SetWordCompleter(func(line string, pos int) (
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string, []string, string) {
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return complete(L, line, pos)
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})
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line.SetMultiLineMode(true)
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line.SetTabCompletionStyle(liner.TabPrints)
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for {
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script, err := line.Prompt("> ")
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if err == nil {
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line.AppendHistory(script)
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p := ell.NewParser([]byte(script))
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if program, err := p.Run(); err != nil {
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fmt.Printf("\x1b[31m%s: %s\x1b[0m\n", "parse error", err)
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} else {
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run(L, program)
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}
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} else if err == liner.ErrPromptAborted || err == io.EOF {
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break
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} else {
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fmt.Printf("\x1b[31m%s: %s\x1b[0m\n", "error", err)
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}
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}
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os.Stdout.WriteString("\n")
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}
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