which has an implicit boolean test in it.
Actually, an implicit defined() test in it: 
$ perl -MO=Deparse -e'while (<INPUT>) {}'
while (defined($_ = <INPUT>)) {
    ();
}
-e syntax OK

[download]
so that e.g. a 0 with no following newline at the end of a file still goes into the body of the loop.

In reply to Re^2: Explaining Perl truth to beginners by ysth
in thread Explaining Perl truth to beginners by shemp

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