Re: Why is Elisp slow?

[Stefan Monnier]

>> Similarly, you'll need to rewrite all the functions/macros like CONSP,
>> SYMBOLP, FIXNUMP, XCAR, XCDR, make_fixnum, ...  Performance of those
>> is important.
>
> Why would you not use the default CL’s defun, car, cdr, symbol-p,
> cons-p, etc, etc?

I'm talking the work needed to adapt Emacs's C code, e.g:

    DEFUN ("get-buffer-window", Fget_buffer_window, Sget_buffer_window, 0, 2, 0,
           doc: /* Return a window currently displaying BUFFER-OR-NAME, or nil 
if none.
    BUFFER-OR-NAME may be a buffer or a buffer name and defaults to
    the current buffer.
    
    The optional argument ALL-FRAMES specifies the frames to consider:
    
    - t means consider all windows on all existing frames.
    
    - `visible' means consider all windows on all visible frames.
    
    - 0 (the number zero) means consider all windows on all visible
        and iconified frames.
    
    - A frame means consider all windows on that frame only.
    
    Any other value of ALL-FRAMES means consider all windows on the
    selected frame and no others.  */)
         (Lisp_Object buffer_or_name, Lisp_Object all_frames)
    {
      Lisp_Object buffer;
    
      if (NILP (buffer_or_name))
        buffer = Fcurrent_buffer ();
      else
        buffer = Fget_buffer (buffer_or_name);
    
      if (BUFFERP (buffer))
        return window_loop (GET_BUFFER_WINDOW, buffer, true, all_frames);
      else
        return Qnil;
    }


-- Stefan