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Re^2: "2" | "8" = ":" and 2|8=10

by JavaFan (Canon)
on Nov 04, 2011 at 12:39 UTC ( #935912=note: print w/ replies, xml ) Need Help??


in reply to Re: "2" | "8" = ":" and 2|8=10
in thread "2" | "8" = ":" and 2|8=10

Bitwise operators are the only place where there's a difference between strings and numbers.
No. It matters for post-increment as well.
BTW This difference does not fit into the philosophy of Perl, where you should not be able to distinguish between strings and numbers, so this is actually a language design flaw.
It's a deliberate decision, and well worth the offset. It allows you to use bitfields that aren't restricted to 32 (or 64) bits.


Comment on Re^2: "2" | "8" = ":" and 2|8=10
Re^3: "2" | "8" = ":" and 2|8=10
by bart (Canon) on Nov 04, 2011 at 12:46 UTC
    Bitwise operators are the only place where there's a difference between strings and numbers.
    No. It matters for post-increment as well.
    I think you're wrong there. Postincrement only works different for strings if they start with a letter. For strings like "199" it makes no difference: you just get 200. And other strings apparently are converted to a number first, as $x = "2A"; $x++ produces 3.
    It's a deliberate decision, and well worth the offset. It allows you to use bitfields that aren't restricted to 32 (or 64) bits.
    Yes, I don't question the functionality, that is useful. But the typical Perl thing to do would have been to provide different operators for strings and for numbers. Just as with = vs eq and + vs ..
      I think you're wrong there. Postincrement only works different for strings if they start with a letter. For strings like "199" it makes no difference: you just get 200. And other strings apparently are converted to a number first, as $x = "2A"; $x++ produces 3.
      $ perl -E '$x = $y = "A3"; $y + 0; $x++; $y++; say "$x $y"' A4 1 $
      The difference is, $y has an integer (as well as a string value), where $x doesn't. And hence, the post-increment value differs.

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