Update
This node was written partially because I didn't grok the point that chipmunk was making, but I believe it still serves as a useful clarification of the quote below. The important point here is that chipmunk is talking about the Benchmark _file_ and not package. See the follow ups for some interesting implications of this subtle difference. Also I have removed the later portion of the quoted sentence 'where the lexical @a and @b are not in scope ' because it appears I am discussing the lexical variables, whereas I am not. My apologies.
End Update

The eval of the code snippets occurs within Benchmark,

Actually, this isn't correct. Benchmark goes through some interesting (not necessarily completely correct either)contortions to execute code from the package it was called from, in this case main.

This can be seen from this snippet from Benchmark::runloop which is the primary timing routine in Benchmark. (BTW, i only know this cause ive been working on a OO version of Benchmark, coming Real Soon Now to the Code Catacombs :-)

   # find package of caller so we can execute code there
    my($curpack) = caller(0);
    my($i, $pack)= 0;
    while (($pack) = caller(++$i)) {
    last if $pack ne $curpack;
    }

    my ($subcode, $subref);
    if (ref $c eq 'CODE') {
    $subcode = "sub { for (1 .. $n) { local \$_; package $pack; &\$c; 
+} }";
        $subref  = eval $subcode;
    }
    else {
    $subcode = "sub { for (1 .. $n) { local \$_; package $pack; $c;} }
+";
        $subref  = _doeval($subcode);
    }
[download]

Oh and a note to andreychek I dont think that including print,warn statements in a benchmark (unless warn() is what you are benchmarking) is a good idea. The overhead of them executing probably drowns out the difference between the functions. Yves / DeMerphq
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