Re: [SPOILER] Re: New Quiz: "What does this code do?" (1-December-2006)

Joshua Kronengold wrote:

>As of 5.8.5, perlre says this:
>
>  The numbered match variables ($1, $2, $3, etc.) and the related punctu-
>  ation set ($+, $&, , , and $^N) are all dynamically scoped until
>  the end of the enclosing block or until the next successful match,
>  whichever comes first.  (See "Compound Statements" in perlsyn.)
>
>Which on careful analysis (ie, mine, just now :^) would appear to match
>the  described and tested for behavior -- that, the dynamic scope of
>numbered match variables expires at the end of their enclosing block,
>making subroutine calls comparatively safe.
>
>As such, the behavior -is- documented -- and can be relied upon when
>coding for modern perls.
>  
>

Yes, but I had to read this a few times to really get it. A new match 
can occur in the same block or another block called from within this 
block. If it occurs in the same block, you clobber $n. If it occurs in 
another block, you clobber $n until the end of that block. After that 
block $n is again the previous value.

Thanks to everyone on this thread, learn something new every day!

M4