[Python-Dev] Python as a Metro-style App (original) (raw)

"Martin v. Löwis" martin at v.loewis.de
Sat Jan 7 18:57:41 CET 2012

I just tried porting Python as a Metro (Windows 8) App, and failed.

Metro Apps use a variant of the Windows API called WinRT that still allows to write native applications in C++, but restricts various APIs to a subset of the full Win32 functionality. For example, everything related to subprocess creation would not work; none of the byte-oriented file API seems to be present, and a number of file operation functions are absent as well (such as MoveFile).

Regardless, porting Python ought to be feasible, except that it fails fundamentally with the preview release of Visual Studio.

The problem is that compilation of C code is apparently not supported/tested in that preview release. When compiling a trivial C file in a Metro app, the compiler complains that a temporary file ending with "md" could not be found, most likely because the C compiler failed to generate it, whereas the C++ compiler would.

I tried compiling the Python sources as C++, but that produced hundreds of compilation errors. Most of them are either about missing casts (e.g. from int to enum types, or from void * to other pointer types), or about the "static forward" declarations of type objects.

For the latter, anonymous namespaces should be used. While it is feasible to replace

static PyTypeObject foo; ... static PyTypeObject foo = { ... };

with

Py_BEGIN_STATIC PyTypeObject foo; Py_END_STATIC ... Py_BEGIN_STATIC PyTypeObject foo = { ... }; Py_END_STATIC

I'm not sure whether such a change would be accepted, in particular as Microsoft might fix the bug in the compiler until the final release of Windows 8.

Regards, Martin

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