// // Copyright (c) 2018, Přemysl Janouch
// // 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, pos int) ( head string, completions []string, tail string) { tail = string([]rune(line)[pos:]) lastSpace := strings.LastIndexAny(string([]rune(line)[:pos]), " ()[]{};\n") if lastSpace > -1 { head, line = line[:lastSpace+1], line[lastSpace+1:] } for name := range L.Globals { if strings.HasPrefix(strings.ToLower(name), line) { completions = append(completions, name) } } for name := range L.Native { if strings.HasPrefix(strings.ToLower(name), line) { completions = append(completions, 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.SetWordCompleter(func(line string, pos int) ( string, []string, string) { return complete(L, line, pos) }) 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") }