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Re: Learning to code by reading code

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"Rod Pemberton" <do_not_have@noavailemail.cmm> wrote in message
news:jhvobn$ujr$1@speranza.aioe.org...
> "Juha Nieminen" <nospam@thanks.invalid> wrote in message

>> The question is: Would it be *efficient*?
>
> No, it wouldn't.  There is no such thing as an "*efficient*" interpreter
> as
> compared to compiled native code.

In the case of a scripting language, this is largely irrelevant.

If all the language does is invoke other programs, then there would be no
measureable difference between an interpreter, and a native code version.

It also depends on how the language is used; it might be 100 times slower
than native code, but if runtimes are small anyway, then there may not be
much advantage in taking only 1msec to do something instead of 100msec.

> There are two fundamental problems with
> interpreters that can't be overcome: 1) they reimplement the mechanisms of
> assembly language which slows things down alot

An interpreter may well be *implemented* in assembly language. Every
instruction that the interpreter deals with could be implemented by a
carefully hand-crafted and optimised block of assembly code! Sometimes
better than automatically compiled code.

 2) they can't optimize and
> compile code sequences which dramatically slows down loops and other
> control-flow.

Tell that to the guy who implemented the LuaJIT interpreter. Numeric
benchmarks are often faster than optimised C!

>> [...] the resulting C code is usually completely unreadable
>> and unusable by a human being.

I used to find that anyway, even when not generated by a machine..

> True, but if you coded that feature yourself, it doesn't have to be
> coded as "butchered" code.
>
>> Even then it would probably be hard to match the speed of an actual
>> compiler of the original language.
>
> I don't believe that.  C has had some of the most intensive research into
> language optimizations.  Other languages just haven't had the time and
> research put into them.

C is pretty good, but it has to spend a lot of time recognising constructs
in the source code could be expressed directly in a higher level language 
and which can be executed directly (vector operations for example). It 
doesn't always manage to do that.

And if implementing something unusual, you can often write almost directly
from pseudo-code in a higher level language, but a quick, throwaway
implementation in C may well be slower; you need to spend time with C in
achieving what's already been done inside the interpreter.

-- 
Bartc 

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Re: Learning to code by reading code (was: The way to read STL source code) "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2012-02-18 19:00 -0500
  Re: Learning to code by reading code "MikeWhy" <boat042-nospam@yahoo.com> - 2012-02-18 22:34 -0600
  Re: Learning to code by reading code "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2012-02-19 03:54 -0500
    Re: Learning to code by reading code "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> - 2012-02-19 10:42 +0100
      Re: Learning to code by reading code "BartC" <bc@freeuk.com> - 2012-02-19 22:34 +0000
        Re: Learning to code by reading code "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> - 2012-02-20 12:22 +0100
    Re: Learning to code by reading code "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2012-02-20 03:39 -0500
  Re: Learning to code by reading code "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2012-02-19 03:54 -0500
    Re: Learning to code by reading code Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-02-19 08:40 -0800
      Re: Learning to code by reading code "MikeWhy" <boat042-nospam@yahoo.com> - 2012-02-19 13:17 -0600
        Re: Learning to code by reading code Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-02-20 02:32 -0800
          Re: Learning to code by reading code "io_x" <a@b.c.invalid> - 2012-02-20 13:02 +0100
            Re: Learning to code by reading code Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-02-20 05:09 -0800
              Re: Learning to code by reading code "io_x" <a@b.c.invalid> - 2012-02-20 15:11 +0100
                Re: Learning to code by reading code Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-02-20 07:39 -0800
      Re: Learning to code by reading code "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2012-02-20 04:14 -0500
        Re: Learning to code by reading code "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> - 2012-02-20 11:14 +0100
          Re: Learning to code by reading code Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-02-20 05:13 -0800
        Re: Learning to code by reading code Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-02-20 02:49 -0800
          Re: Learning to code by reading code "io_x" <a@b.c.invalid> - 2012-02-20 13:02 +0100
            Re: Learning to code by reading code Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-02-20 05:18 -0800
              Re: Learning to code by reading code "BartC" <bc@freeuk.com> - 2012-02-20 13:53 +0000
                Re: Learning to code by reading code Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-02-21 01:32 -0800
                Re: Learning to code by reading code "io_x" <a@b.c.invalid> - 2012-02-21 16:16 +0100
                Re: Learning to code by reading code Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-02-21 08:40 -0800
          Re: Learning to code by reading code "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2012-02-20 17:36 -0500
            Re: Learning to code by reading code Dombo <dombo@disposable.invalid> - 2012-02-21 00:45 +0100
              Re: Learning to code by reading code "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2012-02-21 04:35 -0500
                Re: Learning to code by reading code Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-02-21 08:48 -0800
                Re: Learning to code by reading code Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-02-22 00:12 -0800
                Re: Learning to code by reading code "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2012-02-22 06:12 -0500
                Re: Learning to code by reading code Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-02-22 04:30 -0800
                Re: Learning to code by reading code Geoff <geoff@invalid.invalid> - 2012-02-22 10:45 -0800
                Re: Learning to code by reading code Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-02-23 01:12 -0800
                Re: Learning to code by reading code "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2012-02-23 07:34 -0500
                Re: Learning to code by reading code Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-02-23 05:46 -0800
                Re: Learning to code by reading code "io_x" <a@b.c.invalid> - 2012-02-24 08:38 +0100
                Re: Learning to code by reading code "io_x" <a@b.c.invalid> - 2012-02-24 08:40 +0100
                Re: Learning to code by reading code "io_x" <a@b.c.invalid> - 2012-02-24 09:38 +0100
                Re: Learning to code by reading code "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2012-02-25 05:25 -0500
                Re: Learning to code by reading code Dombo <dombo@disposable.invalid> - 2012-02-25 12:50 +0100
                Re: Learning to code by reading code Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-02-25 06:13 -0800
                Re: Learning to code by reading code Gareth Owen <gwowen@gmail.com> - 2012-02-26 07:20 +0000
            Re: Learning to code by reading code Juha Nieminen <nospam@thanks.invalid> - 2012-02-21 08:23 +0000
              Re: Learning to code by reading code Juha Nieminen <nospam@thanks.invalid> - 2012-02-21 08:43 +0000
                Re: Learning to code by reading code "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2012-02-21 04:47 -0500
                Re: Learning to code by reading code Juha Nieminen <nospam@thanks.invalid> - 2012-02-21 10:09 +0000
                Re: Learning to code by reading code "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2012-02-22 05:38 -0500
              Re: Learning to code by reading code "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2012-02-21 04:31 -0500
                Re: Learning to code by reading code Juha Nieminen <nospam@thanks.invalid> - 2012-02-21 10:05 +0000
                Re: Learning to code by reading code "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> - 2012-02-21 12:21 +0100
                Re: Learning to code by reading code "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2012-02-22 06:04 -0500
                Re: Learning to code by reading code "BartC" <bc@freeuk.com> - 2012-02-21 11:01 +0000
                Re: Learning to code by reading code "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2012-02-22 05:59 -0500
                Re: Learning to code by reading code "BartC" <bc@freeuk.com> - 2012-02-22 12:59 +0000
                Re: Learning to code by reading code "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2012-02-23 07:03 -0500
                Re: Learning to code by reading code "BartC" <bc@freeuk.com> - 2012-02-24 14:20 +0000
            Re: Learning to code by reading code Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-02-21 01:27 -0800
        Re: Learning to code by reading code Peter Remmers <p.remmers@expires-2011-04-30.arcornews.de> - 2012-02-20 22:25 +0100
          Re: Learning to code by reading code Jorgen Grahn <grahn+nntp@snipabacken.se> - 2012-02-26 08:47 +0000
            Re: Learning to code by reading code "BartC" <bc@freeuk.com> - 2012-02-26 10:55 +0000
        Re: Learning to code by reading code Nomen Nescio <nobody@dizum.com> - 2012-02-22 08:59 +0100
          Re: Learning to code by reading code "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2012-02-22 05:59 -0500
            Re: Learning to code by reading code Nomen Nescio <nobody@dizum.com> - 2012-02-22 13:47 +0100
              Re: Learning to code by reading code "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2012-02-23 06:21 -0500
        Re: Learning to code by reading code Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-02-22 00:08 -0800
  Re: Learning to code by reading code "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2012-02-19 03:54 -0500
  Re: Learning to code by reading code Marco van de Voort <marcov@toad.stack.nl> - 2012-02-19 11:27 +0000

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