Mailman 3 May 2011 - cython-devel

Bug in ord(Py_UNICODE) optimization
by John Ehresman May 27, 2011

May 27, 2011

Hi, ord() applied to a Py_UNICODE typed variable seems to yield a 1 character unicode string rather than an integer. The following doctest fails when added to unicodefunction.pyx: def Py_UNICODE_ord(unicode s): """ >>> Py_UNICODE_ord(u' ') 32 """ cdef Py_UNICODE u u = s[0] return ord(u) Thanks, John

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Re: [Cython] [cython] Openmp (#30)
by Stefan Behnel May 27, 2011

May 27, 2011

[regarding the code for analysing uninitialised variables in the OpenMP branch] dagss, 27.05.2011 10:32: > I suggest this: > > a) Vitja and Stefan notifies Mark of any issues that stops control flow > analysis from going into trunk (outright collisions etc.). Those have > prioritiy over fused types work etc (although I guess Mark don't have > much GSoC time the next month). > > b) Come July, when control flow analysis is presumably in master, Mark > takes a pass and removes any duplicated logic. > > Thoughts? I don't think there are any collisions, it's just that Vitja is currently removing the old visitor based attempts of doing variable initialisation analysis. Getting yet another one in while getting rid of the old ones is a rather unnecessary duplication of effort. I suggest we rebase Vitja's branch when the current test issues are solved, then we'll see if there are any issues with the parallel looping code. I'm in favour of merging the control flow branch ASAP, simply because it's such a great feature. I already disabled two tests in Mark's code that relied on uninitialised variables being None. There are likely others (way older ones) that were written with such misfeatures in mind. Stefan

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Re: [Cython] [cython] Initial startswith / endswith optimization (#35)
by Robert Bradshaw May 26, 2011

May 26, 2011

On Wed, May 25, 2011 at 12:37 PM, jpe <reply+i-954759-90be1c778e144f2c17b3665667d3d62b01062479(a)reply.github.com> wrote: > This optimizes startswith / endwith optimization for str. Cool. >What's unclear to me is how str will be mapped to either bytes or unicode; I assume at some point cython will have a python3 syntax mode where str is unicode, print is a function, etc (if it doesn't have one already). Should I be using the type name bytes instead of str? I'm glad you're thinking about this question, some explanation of the various string types is at http://wiki.cython.org/enhancements/stringliterals Probably the way to do this is have one optimization for bytes, one for unicode, and then have a third type for str that dispatches to the one or the other depending on the python version (using #define). - Robert

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Re: [Cython] [cython] Initial startswith / endswith optimization (#35)
by Stefan Behnel May 26, 2011

May 26, 2011

jpe, 25.05.2011 21:37: > This optimizes startswith / endwith optimization for str. What's > unclear to me is how str will be mapped to either bytes or unicode > Should I be using the type name bytes instead of str? Different things. Robert already pointed you to the Wiki site. Basically, "str" is evaluated at C compile time to become either bytes or unicode, depending on the CPython version it is being compiled against. The same applies to literals. (And believe me, there has gone some work into this behaviour...) > I assume at some point cython will have a python3 syntax mode where str is > unicode, print is a function, etc (if it doesn't have one already). We have both a "-3" command line option and the "language_level=3" compiler directive for that. Stefan

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Small issue with buffers
by Vitja Makarov May 25, 2011

May 25, 2011

Hi! Trying to fix some tests broken by CF I've found this issue: def fuu(object[int] b1): cdef object[int] b2 print b1 buff.c: In function ‘__pyx_pf_4buff_fuu’: buff.c:504: error: ‘__pyx_bstruct_b2’ undeclared (first use in this function) buff.c:504: error: (Each undeclared identifier is reported only once buff.c:504: error: for each function it appears in.) buff.c: In function ‘__Pyx_BufFmt_TypeCharToAlignment’: buff.c:809: warning: unused parameter ‘is_complex’ -- vitja.

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subclassing list
by Vitja Makarov May 25, 2011

May 25, 2011

cdef class Foo(list): pass def foo(): f = Foo() f.append(1) gcc -g3 -fPIC -I/usr/include/python2.6 -g3 -W -Wall -c -o lll.o lll.c lll.c: In function ‘__pyx_pf_3lll_foo’: lll.c:468: error: ‘struct __pyx_obj_3lll_Foo’ has no member named ‘None’ Is this a known bug? -- vitja.

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CF and finally clause
by Vitja Makarov May 25, 2011

May 25, 2011

Hi! When I create control flow graph I have to visit finally clause twice. This is required because of different outputs should be generated for success and exception case: try: a = might_raise() finally: pass # 'a' might be uninitialized here print(a) # and definitely defined here So after tracking both cases I have to merge states back because same code is generated for each. Maybe it's a good idea to split success/exception case by copying it at PostParse transform? -- vitja.

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Scope resolution in a Visitor
by Romain Guillebert May 24, 2011

May 24, 2011

Hi I'm doing the PyPy backend for Cython Summer of Code project and I would like to know if there is a way of getting the AST Node responsible for the declaration of a variable. For example : def func(): def func(): pass func() In the situation where I'm currently traversing the function call, I would like to get the function declaration node. Is there already something to do that ? Cheers Romain

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nonecheck directive
by Stefan Behnel May 22, 2011

May 22, 2011

Hi, why is the "nonecheck" directive set to False by default? Shouldn't it rather be a "I know what I'm doing" option that allows advanced users to trade speed for safety? The reason I'm asking is that I just enabled its evaluation in NoneCheckNode and immediately got crashes in the test suite. So its currently only half-heartedly safe because it's not being evaluated in a lot of places. That's a rather fragile situation, not only for refactorings. Stefan

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Scoped expressions and generators problem
by Vitja Makarov May 20, 2011

May 20, 2011

I don't know how to handle scopedexprs in generators, here are some examples: [(yield i) for i in l] or [i for i in yield] In Python3 language mode scoped expression is created for list comprehension and loop variable is moved there. So now it isn't stored inside generator closure and is lost between yields. Btw there is one more problem I hope that's easy to solve: yield expression inside scoped expression is counted twice. -- vitja.

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