Why is python not written in C++ ?
in [Python]
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From: Carl Banks on 9 Aug 2010 14:08 On Aug 9, 6:39 am, Ulrich Eckhardt <eckha...(a)satorlaser.com> wrote: > candide wrote: > > Python is an object oriented langage (OOL). The Python main > > implementation is written in pure and "old" C90. Is it for historical > > reasons? > > The fact that Python is OOP doesn't mean that the implementation of it has > to be written using an OOP language. > > Other than that, I'm actually surprised that nobody mentioned that Python > actually _is_ written in C++. Yes, it's restricted to a subset thereof that > is compatible to C, but you could also claim that it was written in a > subset of C compatible to C++. > > :) I highly doubt the Python source would build with a C++ compiler. C++ is "'mostly' 'backwards' compatible" with C insofar as you can pretty easily write C code that is also legal (and semantically equivalent) C++. But if you don't actively try to write code that is compatible with both languages, chances are the C code will invoke one of those "'minor' 'backwards' incompatibilies", the most common one being failure to cast a pointer. Carl Banks
From: Christian Heimes on 9 Aug 2010 14:27 > I highly doubt the Python source would build with a C++ compiler. > > C++ is "'mostly' 'backwards' compatible" with C insofar as you can > pretty easily write C code that is also legal (and semantically > equivalent) C++. But if you don't actively try to write code that is > compatible with both languages, chances are the C code will invoke one > of those "'minor' 'backwards' incompatibilies", the most common one > being failure to cast a pointer. Indeed: g++ -pthread -c -fno-strict-aliasing -g -O2 -DNDEBUG -g -fwrapv -O3 -Wall -I. -IInclude -I./Include -DPy_BUILD_CORE -o Parser/parsetok.o Parser/parsetok.c Parser/parsetok.c: In function 'node* parsetok(tok_state*, grammar*, int, perrdetail*, int*)': Parser/parsetok.c:251: error: invalid conversion from 'void*' to 'char*' make: *** [Parser/parsetok.o] Error 1 Beside from several invalid conversions Python could most probably be compiled with a g++ compiler. I once worked on a patch to fix the conversion issues but Martin argued against it. There isn't really a point in cluttering the source with type casts. Christian
From: Ulrich Eckhardt on 10 Aug 2010 03:06 Carl Banks wrote: > I highly doubt the Python source would build with a C++ compiler. As Christian showed, it doesn't. However, look around the sources a bit. There are lots of places where e.g. the returnvalue of malloc() (or, rather, the macro that resolves to something like it) is explicitly type-cast to the according pointer type. When asked on the developers' list, it was said that this was intended for compatibility with C++, e.g. in cases where people want to embed Python into their C++ projects. Of course, this contradicts Christian's statement that C++ compatibility wasn't considered useful enough. *shrug* Uli -- Sator Laser GmbH Geschäftsführer: Thorsten Föcking, Amtsgericht Hamburg HR B62 932
From: Lawrence D'Oliveiro on 10 Aug 2010 06:28 In message <mailman.1863.1281378450.1673.python-list(a)python.org>, Christian Heimes wrote: > There isn't really a point in cluttering the source with type casts. Makes you wonder why they bothered using a typed language at all.
From: Carl Banks on 10 Aug 2010 14:49
On Aug 10, 12:06 am, Ulrich Eckhardt <eckha...(a)satorlaser.com> wrote: > Carl Banks wrote: > > I highly doubt the Python source would build with a C++ compiler. > > As Christian showed, it doesn't. However, look around the sources a bit. > There are lots of places where e.g. the returnvalue of malloc() (or, > rather, the macro that resolves to something like it) is explicitly > type-cast to the according pointer type. When asked on the developers' > list, it was said that this was intended for compatibility with C++, e.g. > in cases where people want to embed Python into their C++ projects. Of > course, this contradicts Christian's statement that C++ compatibility > wasn't considered useful enough. I question why it needs to be compatible with C++ to be able to embed Python in a C++ project. How many C++ compilers out there don't come bundled with a C compiler? Carl Banks |