The line 
while ($a < $b) if not $error
 { $a++; }

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is more clearly interpreted by perl to be  while ($a < $b) if not $error{ $a++; }. Perl thinks $error{ $a++ } is a hash reference to %error. A construct that would DWYM would be (parenthesis not strictly necessary)
 
(!$error) && ($a++ while ($a < $b))

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PJ
use strict; use warnings; use diagnostics; (if needed)

In reply to Re: backwards if and while looping by periapt
in thread backwards if and while looping by jcpunk

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