[Cython] Beginner-friendly tickets

[Anoop Saldanha]

Looks like it was available here
http://docs.cython.org/docs/language_basics.html#integer-for-loops and
http://docs.cython.org/docs/pyrex_differences.html#automatic-range-conversion

On Wed, Mar 18, 2009 at 10:23 PM, Anoop Saldanha <poonaatsoc at gmail.com>wrote:

> Thanks Kurt.  That was helpful.  Looks like the optimization is happening
> at IterationTransform() in the pipeline.
>
>
> On Wed, Mar 18, 2009 at 9:59 PM, Kurt Smith <kwmsmith at gmail.com> wrote:
>
>> 2009/3/18 Anoop Saldanha <poonaatsoc at gmail.com>:
>>
>> [snip]
>>
>> >
>> > But
>> >
>> > cdef int g():
>> >      print "g called"
>> >      return 5
>> >
>> > def f():
>> >     cdef int i
>> >     for i in range(g()):
>> >         print i
>> >     print i
>> >
>> > uses a ForFromStatNode for the "for in" loop!
>>
>> I'm not a core developer, so this is open to correction, but putting
>> in some PrintTree() calls into
>> Cython/Compiler/Main.py:create_pipeline() shows that it starts out as
>> a ForInStatNode and is changed to a ForFromStatNode.  Perhaps because
>> cython inferrs that g returns a C int and it triggers the 'range'
>> optimization.
>>
>> Before any transformations:
>>
>> - (root): ModuleNode(pos=(foo.pyx:1:0))
>>  - body: StatListNode(pos=(foo.pyx:1:0))
>>    - stats[0]: CFuncDefNode(pos=(foo.pyx:1:5))
>>     [removing cdef int g() stuff]
>>    - stats[1]: DefNode(name="f")
>>      - body: StatListNode(pos=(foo.pyx:6:4))
>>        - stats[0]: CVarDefNode(pos=(foo.pyx:6:9))
>>          - base_type: CSimpleBaseTypeNode(pos=(foo.pyx:6:9))
>>          - declarators[0]: CNameDeclaratorNode(pos=(foo.pyx:6:13))
>>        - stats[1]: ForInStatNode(pos=(foo.pyx:8:4)) <== starts out as
>> as ForInStatNode
>>          [snip rest of def f() function body]
>>
>> After all transformations:
>>
>> - (root): ModuleNode(pos=(foo.pyx:1:0))
>>  - body: StatListNode(pos=(foo.pyx:1:0))
>>    - stats[0]: CFuncDefNode(pos=(foo.pyx:1:5))
>>       [snip func body]
>>    - stats[1]: DefNode(name="f")
>>      - body: StatListNode(pos=(foo.pyx:6:4))
>>        - stats[0]: ForFromStatNode(pos=(foo.pyx:8:4))  <== Changed to
>> a ForFromStatNode.
>>          - target: NameNode(type=<CNumericType int>, name="i")
>>          - bound1: IntNode(type=<CNumericType long>)
>>          - bound2: SimpleCallNode(type=<CNumericType int>)
>>            - function: NameNode(type=<CFuncType <CNumericType int>
>> []>, name="g")
>>          - step: IntNode(type=<CNumericType long>)
>>          - body: StatListNode(pos=(foo.pyx:9:8))
>>            - stats[0]: PrintStatNode(pos=(foo.pyx:9:8))
>>              - arg_tuple: TupleNode(type=<PyTuple_Type>)
>>                - args[0]: CoerceToPyTypeNode(type=<PyObjectType>)
>>                  - arg: NameNode(type=<CNumericType int>, name="i")
>>        - stats[1]: PrintStatNode(pos=(foo.pyx:10:4))
>>          - arg_tuple: TupleNode(type=<PyTuple_Type>)
>>            - args[0]: CoerceToPyTypeNode(type=<PyObjectType>)
>>              - arg: NameNode(type=<CNumericType int>, name="i")
>>
>> Kurt
>> _______________________________________________
>> Cython-dev mailing list
>> Cython-dev at codespeak.net
>> http://codespeak.net/mailman/listinfo/cython-dev
>>
>
>
>
> --
> Regards,
> Anoop S.
>
> People who says, "It's not winning or losing that matters, but
> participation", probably lost.
>



-- 
Regards,
Anoop S.

People who says, "It's not winning or losing that matters, but
participation", probably lost.
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