Re: [Tcllib-devel] Asking for comments on a ncgi patch (regexp ->string last/...)

[Jeff H. <je...@ac...>]

Andreas Kupries wrote:
> Is the change below something the Tcl RE bytecompiler does=20
> automagically ? Could it be done ?
>=20
>
https://sourceforge.net/tracker/?func=3Ddetail&atid=3D112883&aid=3D153689=
0&group_id=3D
12883
>=20
> 	using regexp in ::ncgi::nvlist is slower that the
> 	usage of string methods (although it looks better).
> 	regexp also causes problems with bigger data which can
> 	cause ncgi to get stuck (try running it on big post
> 	data).

There are a lot of cases where 'string' methods trump REs for speed.  =
This is
not a case that the bytecompiler tries to outsmart the user - it doesn't =
do
that for any capturing REs.  It would be nice if the RE handled this =
better.
I'm fairly certain that someone with strong determination and strong =
will (to
not go crazy ;) ) would find that the RE code is not efficient for many =
simple
cases.  Unfortunately I don't have the time for this review.  :(

Jeff

> 	replace:
>=20
> 	if {![regexp -- (.*)=3D(.*) $x dummy varname val]} {
>           set varname anonymous
>           set val $x
>       }
>=20
> 	with:
>=20
> 	set idx [string last "=3D" $x]
> 	if {$idx=3D=3D-1} {
> 	   set varname anonymous
> 	  set val $x
> 	} else {
> 	    set varname [string range $x 0 [expr {$idx-1}]]
> 	    set val [string range $x [expr {$idx+1}] end]
> 	}