Re: eepitch with prefixes

[Eduardo Ochs]

Hi Tomas!

On Fri, 8 Apr 2022 at 18:15, Tomas Hlavaty <tom@logand.com> wrote:
> (...)

Let's imagine for a moment an `eepitch-preprocess-line' with lots of
bells and whistles, and a person who is playing with her many
definitions of `eepitch-preprocess-line' and experimenting with
features that can be turned on and off. She has this in her ~/.emacs:


  ;; This block of code is also in:
  ;;   http://angg.twu.net/elisp/eepitch-pl-tools.el.html
  ;;   http://angg.twu.net/elisp/eepitch-pl-tools.el
  ;; (find-anggwget-elisp "elisp/eepitch-pl-tools.el")

  ;; Basic variants of `eepitch-preprocess-line'.
  ;; See: (find-eepitch-intro "3.3. `eepitch-preprocess-line'")
  (setq  eepitch-preprocess-regexp "^#: ")
  (defun eepitch-preprocess-line-0 (line) line)
  (defun eepitch-preprocess-line-1 (line)
    (replace-regexp-in-string eepitch-preprocess-regexp "" line))

  ;; Change `eepitch-preprocess-line'.
  ;; (find-eev "eepitch.el" "eepitch-this-line")
  ;; (find-eev "eepitch.el" "eepitch-this-line" "defun eepitch-preprocess-line")
  ;; Default when not experimenting with new features: same regexp everywhere.
  (defun eepitch-preprocess-line (line)
    (eepitch-preprocess-line-1 line))

  ;; Some tools.
  ;; Tests: (eepitch-pl-get-line)
  ;;        (eepitch-pl-flash 0 2)
  ;;        (eepitch-pl-flash 2 10)
  ;;        (eepitch-pl-flash-re "^;; ?")
  ;;        (eepitch-pl-flash-re  ";; ?")
  ;;        (eepitch-pl-flash-re (rx alpha))
  ;;        (eepitch-pl-flash-re (rx digit))
  ;;
  (defun eepitch-pl-flash (offset1 offset2 &optional face duration)
    "`ee-flash' the part of current line between OFFSET1 and OFFSET2."
    (ee-flash (+ (ee-bol) offset1)
              (+ (ee-bol) offset2)
      face duration))

  (defun eepitch-pl-get-line ()
    (buffer-substring-no-properties (ee-bol) (ee-eol)))

  (defun eepitch-pl-flash-re (re &optional subexp face duration)
    (let* ((line (eepitch-pl-get-line)))
      (when (string-match re line)
        (eepitch-pl-flash
         (match-beginning (or subexp 0))
         (match-end       (or subexp 0))
         face duration))))


The function `eepitch-pl-flash', `eepitch-pl-get-line', and
`eepitch-pl-flash-re' are tools that she thinks that are well-written
enough, and that are used by some her experiments - that are scattered
thought several files... and she is experimenting with:

  1) highlighting the prefix that is ignored

  2) variants of `eepitch-preprocess-line' that choose a different
     "prefix that is ignored" depending on the major mode

  3) variants of `eepitch-preprocess-line' that replace things like
     "⟦password⟧" by other strings - and that highlight the replaced
     parts

  4) variants with hacks to support rest-of-line comments in SmallTalk

She needs simple ways to turn her experiments off when they break. And
she thinks - and me too - that lines like these are good enough:

  (defun eepitch-preprocess-line (line) (eepitch-preprocess-line-0 line))
  (defun eepitch-preprocess-line (line) (eepitch-preprocess-line-1 line))
  (defun eepitch-preprocess-line (line) (eepitch-preprocess-line-2 line))

...and that is more or less why I prefer to keep this as the default
definition for `eepitch-preprocess-line' in eepitch.el:

  (defun eepitch-preprocess-line (line) line)

I don't have any idea of how to write an `eepitch-preprocess-line'
that is "general enough", and right now I prefer to force people who
use alternative definitions for it to redefine
`eepitch-preprocess-line' themselves explicitly...

Note that this

> Even better would be, if eev automatically figured out buffer mode
> specific single line comments and dealt with those automatically. I
> don't know how to do this.

and

> Another issue I am facing is that my email client indents email
> threads with spaces so I cannot run eepitch blocks directly from
> emails with the default eepitch config. It would be great if that
> worked without any custom user configuration.

can both be handled by the idea (2) above... but I think that this

> Even better would be, if eev automatically figured out buffer mode
> specific single line comments and dealt with those automatically. I
> don't know how to do this.

is not a good idea _now_ - it would be great to have posts here in the
mailing list showing code to make the "prefix that is ignored" depend
on the major mode, but I prefer to keep the default
`eepitch-preprocess-line' as a no-op...

  Cheers,
    Eduardo Ochs
    http://angg.twu.net/#eev
    http://angg.twu.net/#eev-blogposts