On 12/6/2013 11:34 PM, Maxim Fomin wrote:
On Friday, 6 December 2013 at 23:19:22 UTC, Walter Bright wrote:
I see a lot of C code that does strlen() over and over. I think Tango's XML
parser showed what can be done in D versus any known C implementation. It took
maximal advantage of D's slicing abilities to avoid copying.
Dmitry's regex also showed huge gains over C regex implementations.
This C code is easy to fix.
No it isn't. Have you tried? I have, it's very hard to retrofit a non-trivial C
program with carrying around all the string lengths as a separate value. Call
just about any C library, and you're back again to strlen(). It's even harder to
get away from strlen() in C++ because it inextricably tied std::string to it.
A lot of capable people worked for decades on C regexen, yet Dmitry blew them
away with his D version.
Unlike in D there is no way to fix constant gc
allocations and if gc is disabled, you say good buy to: classes, interfaces,
exceptions, dynamic arrays, delegates, lambdas, AA arrays, etc.
I think you're way exaggerating. (Note that C has none of those features.)
By the way, if you mentioned strlen(), lets compare printf() and writeln().
Sure. Feel free.
But summing this issues altogether makes D code cannot compete with C code.
This is simply not true. You might want to look at Don's presentation at
Dconf2013 where he explains that Sociomantic uses D not for romantic reasons but
because the performance of it gives a competitive edge.
examples from hall of D mangling, mangling is so big, that forum software goes
astray)
Long mangling is not an inherent language characteristic, as that thread
suggests improvements.
But this is flaw in implementation. Language and its advantages are dead without
implementation.
I've worked with a lot of C compilers that had lousy, buggy implementations and
lousy code generation. I'm being careful here to deal with characteristics of
the language, not the implementation.
And again, notice that you are speaking about 'hypothetical advantages'
(language advantages) which implies two things:
1) current efficiency is worse when comparing with some benchmark
2) despite many years of development, community failed to realize these
advantages.
This makes me think that probably there is another reason of why code is less
efficient, for example fundamental characteristics of the language make him hard
to be quick. This is not bad per se, but saying that language code can be faster
than C, taking into account some many problems with D, looks like advertisement,
rather then technical comparison.
There are several D projects which show faster runs than C. If your goal is to
pragmatically write faster D code than in C, you can do it without too much
effort. If your goal is to find problem(s) with D, you can certainly do that, too.
