Re: [9fans] du and find

[Rudolf Sykora <rudolf.sykora@gmail.com>]

On 3 May 2010 14:18, Akshat Kumar <akumar@mail.nanosouffle.net> wrote:
> Forgive my ignorance and irrelevance to this topic,
> but what are the advantages of Perl's regular
> expressions, over the implementation we have
> currently in Plan 9?

Regexps in Plan9 are on one hand much less powerful than Perl's, on
the other hand they are (thanks to their simplicity) much quicker.
Often one doesn't need Perl's power and in such a case Plan9's regexps
are better. But in sometimes...

Just compare:
http://www.amk.ca/python/howto/regex/
to
regexp(7)

... particularly e.g. Lookahead Assertions, Non-capturing and Named Groups.

It's always been easier for me to use python's/perl's regular
expressions when I needed to process a text file than to use plan9's.
For simple things, e.g. while editing an ordinary text in acme/sam,
plan9's regexps are just fine.

Also read Russ Cox text:
http://swtch.com/~rsc/regexp/regexp1.html

Ruda