Method Loop

interpreter/interpreter.go:349–395

Loop reads lines from stdin and performs the commands.

()

// Loop reads lines from stdin and performs the commands.
func (i *Interpreter) Loop() error {
	i.ShowHelp()
	for {
		line, err := nextLine()
		if err != nil {
			return err
		}
		switch {
		case line == "::help":
			i.ShowHelp()

		case strings.HasPrefix(line, "::load "):
			if err := i.Load(strings.TrimPrefix(line, "::load ")); err != nil {
				fmt.Fprintf(i.out, "load failed: %v\n", err)
			}

		case line == "::pop":
			i.Pop()

		case strings.HasPrefix(line, "::show "):
			if err := i.Show(strings.TrimPrefix(line, "::show ")); err != nil {
				fmt.Fprintf(i.out, "show failed: %v\n", err)
			}

		case strings.HasPrefix(line, "?"):
			if err := i.QueryInteractive(strings.TrimPrefix(line, "?")); err != nil {
				fmt.Fprintf(i.out, "error evaluating query: %v\n", err)
			}

		default:
			savedBuffer := i.buffer
			clauseText := line
			for !strings.HasSuffix(clauseText, ".") && !strings.HasSuffix(clauseText, "!") {
				nextLine, err := nextLineWithPrompt(continuedPrompt)
				if err != nil {
					return err
				}
				clauseText = clauseText + nextLine
			}

			if err := i.Define(clauseText); err != nil {
				fmt.Fprintf(i.out, "definition failed: %v\n", err)
				i.buffer = savedBuffer
			}
		}
	}
}

// Preload evaluates decls and clauses before any interactive evaluation takes place.
// This is used for customizing the interpreter.