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Re^17: why are hex values not numbers? (octal)

by Anonymous Monk
on Oct 03, 2016 at 07:38 UTC ( #1173137=note: print w/replies, xml ) Need Help??


in reply to Re^16: why are hex values not numbers? (octal)
in thread why are hex values not numbers?

I had this thought before :)

now perl gives warning

Argument "0x41" isn't numeric in printf

Very clean, things we know are numbers and can unambiguously identify as numbers, we treat as numbers, all other stuff we warn about

But if definition of numeric was expanded to include more ambiguous num formats, then perl would need a new warning

treating "0x41" as numeric , might be wrong thing to do, silence with +"no warnings q/extranumeric/;"

I'm confused why perl-diddler hasn't posted use extranumeric; yet :D

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Re^18: why are hex values not numbers? (octal)
by BrowserUk (Patriarch) on Oct 03, 2016 at 08:38 UTC
    But if definition of numeric was expanded to include more ambiguous num formats, then perl would need a new warning: treating "0x41" as numeric , might be wrong thing to do, silence with "no warnings q/extranumeric/;"

    That's a (the first) plausible approach to the proposition. It is certainly doable; but at what benefit and what cost?

    Ignoring for now the old saw of backward compatibility. (Though it certainly wouldn't be ignored by the only persons whom opinions matter in this regard, namely the denizens of p5p.)

    The "benefit" would be that the programmer expecting non-decimal numbers in string input could write:

    print "%d\n", $string;

    Rather than:

    printf "%d\n", hex( $string );

    And the cost would be implicitly calling hex every time a scalar currently holding a PV, is used in a numeric context.

    That doesn't seem such a bad thing. (At least if it had been that way since the beginning: Ba-w-d co-pa-bil-ty!)

    But, either this is going to warn "might be wrong thing" every time it finds an extranumeric and the programmers who don't want that will have to disable it; or it will be silent and the programmers that do want the warning, will have to explicitly enable it.

    Seems to me that for those few that do, something like this is just as easy:

    sub myHex { no warnings 'digit'; hex( $_[0] }; } printf "%d\n", myHex( $string );

    With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
    Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
    "Science is about questioning the status quo. Questioning authority". I knew I was on the right track :)
    In the absence of evidence, opinion is indistinguishable from prejudice.

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