Why is python not written in C++ ?
in [Python]
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From: John Nagle on 3 Aug 2010 13:44 On 8/1/2010 5:36 PM, Roy Smith wrote: > In article<4c55fe82$0$9111$426a34cc(a)news.free.fr>, > candide<candide(a)free.invalid> wrote: > >> Python is an object oriented langage (OOL). The Python main >> implementation is written in pure and "old" C90. Is it for historical >> reasons? >> >> C is not an OOL and C++ strongly is. I wonder if it wouldn't be more >> suitable to implement an OOL with another one. > > One thing that comes to mind is that it's much easier to distribute C > libraries than C++ libraries. > > If I compile a main program with one C compiler and you compile a > dynamically loaded library with another C compiler on the same box, the > odds are pretty good they'll interoperate without any problems. Not for Python. Extensions have to be built with essentially the same version of the same C compiler used for building Python. This is a major headache. John Nagle
From: Paul Rubin on 3 Aug 2010 14:35 Grant Edwards <invalid(a)invalid.invalid> writes: > There's no computing problem so simple that it can't be solved in a > complex and obtuse manner in C++. > > I know that's true of any language, but from what I've seen over the > years, it "more true" in C++. http://www.willamette.edu/~fruehr/haskell/evolution.html
From: John Bokma on 3 Aug 2010 18:19 Carl Banks <pavlovevidence(a)gmail.com> writes: > On Aug 3, 2:29 am, John Bokma <j...(a)castleamber.com> wrote: [..] >> But they call both the C libraries in the same way. > > Go look at the original claim, the one that you responded to. "It's > much easier to distribute C libraries than C++ libraries." Yup, and if I read it correctly the claim was: and that's why C++ was not chosen. I doubt it. > Hence, "It's much easier to distribute C libraries than C++ > libraries." Yup, but still doesn't exclude C++ from being used to implement a programming language. And I would appreciate some respect, especially from someone who's too lazy to do some editing before posting, thank you. -- John Bokma j3b Hacking & Hiking in Mexico - http://johnbokma.com/ http://castleamber.com/ - Perl & Python Development
From: John Bokma on 3 Aug 2010 18:20 Ethan Furman <ethan(a)stoneleaf.us> writes: > John Bokma wrote: >> Michael Torrie <torriem(a)gmail.com> writes: >> >>> On 08/01/2010 07:09 PM, John Bokma wrote: >>>>> One thing that comes to mind is that it's much easier to >>>>> distribute C libraries than C++ libraries. >>>> In the beginning of C++ there were programs that just converted C++ to C >>>> (frontends). At least that is how the C++ compiler Acorn sold worked. >>>> So I don't think your argument was much true back then. >>> No, he is still right. Each C++ implementation did name mangling >>> differently leading to "C" libraries that had incompatible names and >>> signatures. Also each frontend could have generated incompatible >>> vtables and other C++ structures. So C code generated by one C++ >>> frontend could not easily call C code generated by another C++ frontend. >>> So the same arguments that are made about C++ now were just as valid >>> back then when C++ was merely a fancy preprocessor. >> >> See my other post: I understand that two C++ preprocessors can't call >> each others generated code, but if one uses C++ and knows that one can >> only use shared C libraries on target systems, and not C++ libraries >> that might be present (or more likely not: C++ was new in those days). > > So if Python were written in C++, and an extension was written in C++, > how could the two call each other? Via C. -- John Bokma j3b Hacking & Hiking in Mexico - http://johnbokma.com/ http://castleamber.com/ - Perl & Python Development
From: Carl Banks on 3 Aug 2010 18:56
On Aug 3, 3:19 pm, John Bokma <j...(a)castleamber.com> wrote: > Carl Banks <pavlovevide...(a)gmail.com> writes: > > On Aug 3, 2:29 am, John Bokma <j...(a)castleamber.com> wrote: > > [..] > > >> But they call both the C libraries in the same way. > > > Go look at the original claim, the one that you responded to. "It's > > much easier to distribute C libraries than C++ libraries." > > Yup, and if I read it correctly the claim was: and that's why C++ was > not chosen. I doubt it. I think it was. Not necessarily that GvR made a list of reasons to choose C over C++. But the fact that C++ has almost no interoperability between compilers except via regular C linkage is a major cultural reason why it's avoided for programs that need extensible APIs like Python, which is why language implementors try to avoid it. The availability of C++ fronts that translate to C isn't the slightest bit relevant to this. > > Hence, "It's much easier to distribute C libraries than C++ > > libraries." > > Yup, but still doesn't exclude C++ from being used to implement a > programming language. Well, if you want to write a language that people can write extensions for using something other than the same C++ compiler you used, then your only option is to use "C" external linkage which means that whatever OOP advantages C++ gives you aren't going to be available to extensions. This is true even if you use a C++ front instead of a compiler. Carl Banks |