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-   -   Emacs Lisp vs Perl: Validate Local File Links (http://www.velocityreviews.com/forums/t945367-emacs-lisp-vs-perl-validate-local-file-links.html)

Xah Lee 04-13-2012 05:35 PM

Emacs Lisp vs Perl: Validate Local File Links
 
〈Emacs Lisp vs Perl: Validate Local File Links〉
http://xahlee.org/emacs/elisp_vs_per...ate_links.html

a comparison of 2 scripts.

lots code, so i won't paste plain text version here.

i have some comments at the bottom. Excerpt:

------------------

«One thing interesting is to compare the approaches in perl and emacs
lisp.»

«For our case, regex is not powerful enough to deal with the problem
by itself, due to the nested nature of html. This is why, in my perl
code, i split the file by < into segments first, then, use regex to
deal with now the non-nested segment. This will break if you have <a
title="x < href=z" href="math.html">math</a>. This cannot be worked
around unless you really start to write a real parser.»

«The elisp here is more powerful, not because of any lisp features,
but because emacs's buffer datatype. You can think of it as a
glorified string datatype, that you can move a cursor back and forth,
or use regex to search forward or backward, or save cursor positions
(index) and grab parts of text for further analysis.»

------------------

If you are a perl coder, and disagree, let me know your opinion.
(showing working code is very welcome) My comment about perl there
applies to python too. (python code welcome too.)

Xah

Dan Espen 04-13-2012 06:54 PM

Re: Emacs Lisp vs Perl: Validate Local File Links
 
Xah Lee <xahlee@gmail.com> writes:

> 〈Emacs Lisp vs Perl: Validate Local File Links〉
> http://xahlee.org/emacs/elisp_vs_per...ate_links.html
>
> a comparison of 2 scripts.
>
> lots code, so i won't paste plain text version here.
>
> i have some comments at the bottom. Excerpt:
>
> ------------------
>
> «One thing interesting is to compare the approaches in perl and emacs
> lisp.»
>
> «For our case, regex is not powerful enough to deal with the problem
> by itself, due to the nested nature of html. This is why, in my perl
> code, i split the file by < into segments first, then, use regex to
> deal with now the non-nested segment. This will break if you have <a
> title="x < href=z" href="math.html">math</a>. This cannot be worked
> around unless you really start to write a real parser.»
>
> «The elisp here is more powerful, not because of any lisp features,
> but because emacs's buffer datatype. You can think of it as a
> glorified string datatype, that you can move a cursor back and forth,
> or use regex to search forward or backward, or save cursor positions
> (index) and grab parts of text for further analysis.»
>
> ------------------
>
> If you are a perl coder, and disagree, let me know your opinion.
> (showing working code is very welcome) My comment about perl there
> applies to python too. (python code welcome too.)


Interesting.

Perl, Python, and Lisp have real HTML parsers available.
I've used the ones for Perl and Python.

--
Dan Espen


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