Re: Another issue with thingatpt

[Andreas Roehler <andreas.roehler@easy-emacs.de>]

Bob Rogers schrieb:
>    From: Andreas Roehler <andreas.roehler@easy-emacs.de>
>    Date: Sun, 31 Dec 2006 10:25:35 +0100
>
>    > Both interfaces (ffap and thing-at-point) are already customizable,
>    > though in different ways. 
>
>    There is no `defcustom'-form in thingatpt.el,
>    it's done mostly with `defvar'. Wouldn't conceive that
>    as customizable.
>
> Not in the sense of defcustom, no.  But someone who can't "customize" it
> themselves via setq is probably not going to be able to change these
> hairy regexps and/or char-classes without shooting themselves in the
> foot.  It's not just a matter of understanding Emacs regexps, but
> understanding how thing-at-point uses them.
Probably you are right.
>
>    In any case, it seems to me that users shouldn't need to change the
> regexp proper, since that is defined by RFC3986, just the set of
> punctuation characters to drop at the end. 
Maybe I miss something, but AFAIS the regexp in question is not  derived 
in a strict sense. I give the description from RFC

 here:

;;;;;;;;;;;;;;

      reserved    = gen-delims / sub-delims

      gen-delims  = ":" / "/" / "?" / "#" / "[" / "]" / "@"

      sub-delims  = "!" / "$" / "&" / "'" / "(" / ")"
                  / "*" / "+" / "," / ";" / "="

...


   Characters that are allowed in a URI but do not have a reserved
   purpose are called unreserved.  These include uppercase and lowercase
   letters, decimal digits, hyphen, period, underscore, and tilde.

      unreserved  = ALPHA / DIGIT / "-" / "." / "_" / "~"

;;;;;;;;;;;;;;;

Thats basically what I detect concerning the matter there.

>  The only thing that needs to
> be customized is just the "lose the punctuation" heuristic, IMHO.  And
> the definition of "punctuation" should be enlarged so that it addresses
> Slawomir's issue with parens, which are not even allowed internally.
>
>    The problem mentioned originally however shouldn't occur, as
>
>    ,----
>    | (defvar thing-at-point-url-path-regexp
>    |   "[^]\t\n \"'()<>[^`{}]*[^]\t\n \"'()<>[^`{}.,;]+"
>    |   "A regular expression probably matching the host and filename or 
>    e-mail part of a URL.")
>    `----
>
>    includes that char. The error must reside elsewhere.
>
>    Regards,
>
>    Andreas Roehler
>
> It does include a ";" in the second character class, but both are
> inverted.  The second set is the same as the first set with the addition
> of ".,;", which is why it refuses to match any of these characters at
> the end of the URL.  This would be easier to see if the regexp were
> written this way:
>
> 	(defvar thing-at-point-url-path-regexp
> 		(concat "[^]\t\n \"'()<>[^`{}]*"
> 			"[^]\t\n \"'()<>[^`{}.,;]+")
> 	  "A regular expression probably matching the host and filename or e-mail part of a URL.")
>
> 					-- Bob
Now I see it, thanks a lot.

BTW: What about to drop the `;' from the regexp?
 
Maybe together with the comma-sign, as this char is mentioned too as a 
sub-delimiter.

Other problems:

- Char ' (39, #o47, #x27) now seems excluded, whereas RFC mentiones it as a
sub-delimiter too.

- (defvar thing-at-point-short-url-regexp
  (concat "[-A-Za-z0-9.]+" thing-at-point-url-path-regexp)

misses the underscore in its bracket. (unreserved after RFC)



Andreas