Mailman 3 May 2013 - cython-devel

Re: [Cython] [cython-users] Bug in 0.19 (with example)
by Stefan Behnel May 1, 2013

May 1, 2013

Eric Frederich, 01.05.2013 18:59: > I have discovered a bug in Cython 0.19 > > This code works in 0.15.1 but not in 0.19. > I haven't tested it anywhere in between. > > The following 3 files are listed at the end of this email. > blah.h > blah.pxd > test.pyx > > The errors I get are the following: > test.pyx:3:18: Not allowed in a constant expression > test.pyx:3:18: Array dimension not integer > test.pyx:3:20: Variable type 'char []' is incomplete > > The line is: > cdef char[blah.FOO] x > > If I do: > cdef char[int(blah.FOO)] x > ... I get the following error: Thanks for the report. Looks like a known bug, however, already reported and fixed: http://mail.python.org/pipermail/cython-devel/2013-May/003631.html Stefan

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Re: [Cython] [cython] Autodoc improvements (#216)
by Stefan Behnel May 1, 2013

May 1, 2013

Nikita Nemkin, 18.04.2013 07:07: > Three improvements are included in this patch that I have found helpful when using Sphinx autodoc to document my project: > > 1) Default values preserve and display binary expressions and attribute access. For example, the following function will have its signature displayed as is: > > cpdef func(int flags=MyModule.FLAG1 | MyModule.FLAG2) > > This only affects expressions not reducible at compilation time, i.e. `2+2` will appear as `4`. > > 2) Public/readonly cdef attributes can have docstrings attached, using the [PEP 258 attribute docstring syntax](http://www.python.org/dev/peps/pep-0258/#attribute-docstrings). Example: > > cdef class X: > cdef public attr > """attr docstring""" > > When ``embedsignature=True`` Cython already adds a signature docstring to the generated property (assuming the example above). This patch allows to add an actual docstring too. > > Dosctrings on private cdef attributes will give a warning ("docstring ignored"). > Other forms and uses of attribute docstrings, as described in the PEP 258, are not supported at all (SyntaxError), because there is no standard introspection mechanism designed for them. ([PEP 224](http://www.python.org/dev/peps/pep-0224/) describing such mechanism had been rejected.) > > 3) `bint` appears as `bool` (instead of `int`) in autogenerated signatures, as I suggested on the mailing list. > > Each change is contained in its own commit in case you want to review them separately. > > https://github.com/cython/cython/pull/216 I like 1) and 3), but I'm not sure about 2). Worth noting that PEP 258 was rejected, although definitely for other reasons than this feature. I remember discussing this topic before on the mailing list, but don't remember if we reached a conclusion. I faintly recall that we preferred making the property explicit as soon as there's more to it than a plain 1:1 mapping to the cdef attribute. The above syntax is not wrong, but it also doesn't feel right to me. For example, it's impossible to draw a distinction between the above and something like cdef class X: cdef public attr """ quotes used for commenting out code here. """ And users are unlikely to notice that they just dropped some internals into the docstring of a property they didn't even know they were implementing. IMHO, the user intention is way too unclear in this syntactic construct. Stefan

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Regresion in 0.19
by Lisandro Dalcin May 1, 2013

May 1, 2013

See the example below, the last hunk fails with Cython 0.19. It seems Cython is confusing attribute access with constness. CYTHON=cython echo 'cdef import from *:' > defs.pxd echo ' enum:SIZE' >> defs.pxd echo 'from defs cimport *' > code1.pyx echo 'cdef char buf[SIZE]' >> code1.pyx $CYTHON code1.pyx echo 'cimport defs' > code2.pyx echo 'cdef char buf[defs.SIZE]' >> code2.pyx $CYTHON code2.pyx -- Lisandro Dalcin --------------- CIMEC (INTEC/CONICET-UNL) Predio CONICET-Santa Fe Colectora RN 168 Km 472, Paraje El Pozo 3000 Santa Fe, Argentina Tel: +54-342-4511594 (ext 1011) Tel/Fax: +54-342-4511169

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