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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) {
if result, ok := L.EvalBlock(program, nil); !ok {
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")
}
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