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Re^5: Perl 5 interpreter

by Corion (Pope)
on Jan 12, 2011 at 08:55 UTC ( #881850=note: print w/ replies, xml ) Need Help??


in reply to Re^4: Perl 5 interpreter
in thread Perl 5 interpreter

If "by choice" you mean "the C compiler that my OS vendor uses", I guess too many, especially for OSes that you pay real money for :-)

I think there are some macros that you can't conveniently elide, like dTHX, which expands to "the current thread context" if Perl is compiled with iThreads and "nothing" if threads are not compiled (but you know that). I'm not sure whether having inlined functions is much better, structurally, than having the macros.


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Re^6: Perl 5 interpreter
by BrowserUk (Pope) on Jan 12, 2011 at 09:25 UTC

    21 years is as near as damn it half the life of the industry.

    Can you imagine if say the car industry was still used technology from its half life? Cross-ply tyres, drum brakes and 3-speed gearboxes on your latest car?

    How about planes with canvas and dope wings and piston engines?

    Where would we be if the electronics industry still required the use of discrete transitors?


    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".
    In the absence of evidence, opinion is indistinguishable from prejudice.
      I think it all boils down cost of running them Vs Cost of replacing them. OTOH breaking backwards compatibility won't do good for Perl PR.

        Proprietary hardware/OS manufacturers won't start investing in keeping up with standards until purchasers and programmers start demanding it of them.

        If OS projects like Perl required C99, then the blame doesn't fall on Perl, but the suppliers of antiquated systems software tool chains.


        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".
        In the absence of evidence, opinion is indistinguishable from prejudice.
      21 years is as near as damn it half the life of the industry. Can you imagine if say the car industry was still used technology from its half life?

      Well, actually the car industry is a good example where C89 is still in use.

      There is a lot of software in modern cars, and most is written in C. One of the requirements of the car-manufactors is that the software uses a safe subset of C. And this safe subset is defined by a de-facto standard called MISRA-C (Guidelines for the use of the C-language in critical systems). The current version of it is MISRA-C:2004. In the foreword of that standard you can read:

      While producing MISRA-C:2004 the question of addressing the 1999 C standard arose. At this time only issues with MISRA-C:1998 are addressed due to limited support for C99 on embedded microprocessors.

      So even if current cars contain high-tech features, those features are implemented using an 21-year-old-standard.

      Backward compability to C89 is not as absurd as it seems!

      Rata

        Unless Perl is used on the systems--which almost certainly would not be allowed--that is no reason to limit Perl to that subset.


        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".
        In the absence of evidence, opinion is indistinguishable from prejudice.

      The car industry still uses the same bolts (i.e. same dimension and shape) to fix wheels it used 21 years ago (AFAIK). And probably for the same reason, backwards compatibility/standard compliance

        The car industry still uses the same bolts (i.e. same dimension and shape) to fix wheels it used 21 years ago

        Actually, the almost everything about wheel studs has changed in that time. From the specification of the steel, to the self-locking properties of the threads (fit tolorances), to the torque settings.

        But even if they hadn't, the equivalent might be that C99 uses mostly the same keywords as K&R.


        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".
        In the absence of evidence, opinion is indistinguishable from prejudice.
      Can you imagine if say the car industry was still used technology from its half life?

      Trivia-of-the-Day: The Schrader valve, patented in the 19th century, is still used in its original form on cars today (at least in North America). Depending on the model, your car may easily have a half-dozen of them and is unlikely to have fewer than four.

        I guess I should have phrased that as:

        Can you imagine if say the car industry restricted itself to only using technology from its half life?

        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".
        In the absence of evidence, opinion is indistinguishable from prejudice.

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