Predicate-for allows you to declare and modify a lexical in the same statement: 
s[http://foo.bar.com/][] for (my $dirfilename = $url);

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Using block-for does not put the lexical in the surrounding scope. This is an interesting difference, particularly since -MO=Deparse indicates that the above statement is translated into the block form.

In reply to Re: How do I assign & substitute in one statement? by Roy Johnson
in thread How do I assign & substitute in one statement? by dfaure

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