On Thu, Dec 09, 2004 at 11:18:34AM -0800, Larry Wall wrote:
> On Wed, Dec 08, 2004 at 08:24:20PM -0800, Ashley Winters wrote:
> : I'm still going to prefer using :=, simply as a good programming
> : practice. My mind sees a big difference between building a parse-tree
> : object and just grepping for some word I want in a string. Within a
> : rule{} block, there is no place except the rule object to keep your
> : data (hypothetically -- haha), so it makes sense to have everything
> : capture unless otherwise specified. There's no such limitation in a
> : regular code block, so I don't see the need.
>
> Since regex results are lexically scoped in Perl 6, in a regular
> code block we can do static analysis and determine whether there's
> any possibility that $<foo> is referenced at all, and optimize it
> away in many cases, if it turns out to be high overhead. But as Patrick
> points out, so far capture seems pretty cheap.
It might turn out to be worth optimizing only when ALL of the
"capture" blocks are unused - the saving from avoiding setup
costs together with avoiding the (too small to be a bother
by themselves) incremental costs, might be significantwhen
taken together.
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