comment on

You are seeing the bug in a form where it almost makes sense. However it really is a bug. When I first saw this, it was a bug in Number::Format which turned out to be due to a construct of this form:

  my $foo = $some_init unless test();
[download]

The resulting bug is that if the test failed on 2 calls in a row, you had data from the first call of the function that polluted your output results. This bug was quite subtle and mysterious, and it turned out had been reported to the module author several times over the course of a year, but he was unable to figure out where the bug was.

Since then whenever I have looked at a large body of code for either of the patterns:

  /my .* if/
  /my .* unless/
[download]

and found a match, it has usually resulted in also finding a bug. In short, this is a "feature" that is due to a broken optimization of Perl which, when it is hit in code, is almost always the cause of a bug in that code.

Now if you want static lexical variables without the usual "create a private scope" trick, that is doable in a fairly straightforward manner. In fact I just wrote and tested an implementation, which I just uploaded to CPAN. Hopefully Tie::Static will be accepted and become available shortly. (I intend to post the module to PerlMonks in a short while as well.)

In reply to my $foo if 0; is a bug by tilly
in thread It *is* a feature: mod_perl and 'my $x if 0' by MeowChow

Are you posting in the right place? Check out Where do I post X? to know for sure.
Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:
<code> <a> <b> <big> <blockquote> <br /> <dd> <dl> <dt> <em> <font> <h1> <h2> <h3> <h4> <h5> <h6> <hr /> <i> <li> <nbsp> <ol> <p> <small> <strike> <strong> <sub> <sup> <table> <td> <th> <tr> <tt> <u> <ul>
Snippets of code should be wrapped in <code> tags not <pre> tags. In fact, <pre> tags should generally be avoided. If they must be used, extreme care should be taken to ensure that their contents do not have long lines (<70 chars), in order to prevent horizontal scrolling (and possible janitor intervention).
Want more info? How to link or How to display code and escape characters are good places to start.


more useful options
	PerlMonks