bug#19004: 24.4; Please provide a non-regexp interface to occur

bug#19004: 24.4; Please provide a non-regexp interface to occur

[Juliusz Chroboczek]

Hi.

I like occur a lot, but I find it inflexible -- the matched lines can only
be specified by a regexp.  I'd like to be aple to pass a function to occur
instead of a regexp.

The function should be called with point at the beginning of a line to
match/not match, so that

  (occur regexp)

is equivalent to

  (occur #'(lambda () (looking-at regexp)))

Of course, the function should be able to examine the context around the
line being matched.

-- Juliusz

bug#19004: 24.4; Please provide a non-regexp interface to occur

[Juri Linkov]

> I like occur a lot, but I find it inflexible -- the matched lines can only
> be specified by a regexp.  I'd like to be aple to pass a function to occur
> instead of a regexp.
>
> The function should be called with point at the beginning of a line to
> match/not match, so that
>
>   (occur regexp)
>
> is equivalent to
>
>   (occur #'(lambda () (looking-at regexp)))
>
> Of course, the function should be able to examine the context around the
> line being matched.

At the core of the Occur engine there is the function re-search-forward.
We could move it out to a separate variable e.g. occur-search-function
(as we do for isearch-search-fun-function).  Then you will be able to
override it with your own like

  (let ((occur-search-function 'word-search-forward))
    (occur string))

bug#19004: 24.4; Please provide a non-regexp interface to occur

[Lars Ingebrigtsen]

Juliusz Chroboczek <jch@pps.univ-paris-diderot.fr> writes:

> I like occur a lot, but I find it inflexible -- the matched lines can only
> be specified by a regexp.  I'd like to be aple to pass a function to occur
> instead of a regexp.

(I'm going through old bug reports that unfortunately got little response at
the time.)

There are many ways to search in Emacs, and there's a some packages that
provide structured searching, too.  (For instance, to search based on
semantic qualities in the code.)

Given that, I don't think it makes that much sense to extend the `occur'
command itself -- it does the thing it does very well, and extending it
in that way would make an already complex command even more complicated.

So I'm closing this bug report.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no