New Regular Expression Library

New Regular Expression Library

[Benjamin Purcell]

I have prepared a mercurial bundle that contains the following changes:

1. A new regular expression library.
2. A port of awk to native plan 9.
3. APE regular expression library is removed (only AWK was using it).

The bundle is available at /n/contrib/spew/libregexp.bundle and is
relative to revision f385a29db7f1.

The new regular expression library is faster, uses less memory for
small regular expressions, and will not fail to find matches on
complicated regular expressions that cause the old library to fail.

Porting awk to native plan 9 means awk gets to use the new library.
There is no reason to keep the APE library around since it is snarfed
directly from the old library, it does not implement POSIX libregex
syntax or semantics, and nothing else uses it. I have run bwk's
regression on the new awk, and the only changes are that two floating
point calculations differ by one in the 100ths place and the new awk
succeeds on a couple regular expressions that the old one fails on.

I have been this library in the system for a while now, and it has
seen a good amount of use (in mk, sed, awk, and the plumber) due to
the awk regression suite, numerous full system compilations, and
general usage. I have observed no changes in the system.

Thanks,
spew

Re: [9front] New Regular Expression Library

[Kurt H Maier]

On Thu, Apr 28, 2016 at 08:41:09AM -0500, Benjamin Purcell wrote:
> I have prepared a mercurial bundle that contains the following changes:
> 
> 1. A new regular expression library.

I endorse this.

> 2. A port of awk to native plan 9.

Did you write a new one, or is this related to pap's work?

> 3. APE regular expression library is removed (only AWK was using it).

I endorse this.

khm

Re: [9front] New Regular Expression Library

[Benjamin Purcell]

On Thu, Apr 28, 2016 at 9:19 AM, Kurt H Maier <khm@sciops.net> wrote:
>
> Did you write a new one, or is this related to pap's work?

I started from scratch though I talked to aiju and cinap_lenrek about
difficulties that were encountered with pap's port.