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Re^4: about "say" function

by adefaria (Sexton)
on Aug 13, 2014 at 15:01 UTC ( #1097295=note: print w/replies, xml ) Need Help??

in reply to Re^3: about "say" function
in thread about "say" function

You're kidding right? Why can't those program modules what have a sub/method called say simply rename it? I doubt that every new function that has been introduced worried about possible name conclusions of functions in the past. Why is this different?

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Re^5: about "say" function
by kennethk (Abbot) on Aug 13, 2014 at 15:05 UTC

    Actually, every new function that has been introduced caused worries about possible name collisions. The Perl 5 development crowd is very conscientious about backward compatibility. This concern and the strong culture of testing are probably the best things Perl has going for it (in addition to CPAN and its innate awesomeness, of course). Contrast this with Python (as an example), where the breaks they introduced going from 2.8 to 3.0 have caused large swaths of their community to have two different copies of the Python interpreter installed on their systems.

    #11929 First ask yourself `How would I do this without a computer?' Then have the computer do it the same way.

Re^5: about "say" function
by AppleFritter (Vicar) on Aug 13, 2014 at 17:16 UTC

    In addition to what kennethk has said, there's another upside to these pragmas, especially explicit version requirements: they make your code fail gracefully on older versions.

    Suppose that you do indeed use Perl 5.18 (or a later version), and you want to make use of all the features and goodies it has to offer, so you declare your intent with an explicit use 5.18.0;, and if someone then takes your script and attempts to run it on an older Perl version, they will get a message along the lines of "Perl v5.18.0 required--this is only v5.14.2".

    Same for features. If you ask for a feature that doesn't (yet) exist, e.g. use feature qw/ponies/;, Perl will inform you that "Feature "ponies" is not supported by Perl 5.14.2". No code that fails with unrelated error messages, or (worse) silently, or that (even worse) silently does the wrong thing; no guessing, no headscratching, just a very clear declaration of the programmer's intent, the program's requirement, and the installed Perl's inability to meet the latter.

    Even if it weren't for backwards compatibility, this is a feature. Forward compatibility (running newer scripts on older Perls) matters, too.

Re^5: about "say" function
by ikegami (Pope) on Aug 13, 2014 at 19:20 UTC

    You're kidding right? Why can't those program modules what have a sub/method called say simply rename it?

    Where to start? There's just too many reason to list. There's nothing simple about that.

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