On Jan 29, 2010, at 3:12 PM, Nathaniel Smith wrote:
> On Fri, Jan 29, 2010 at 11:58 AM, Robert Bradshaw
> <[email protected]> wrote:
>> On Jan 29, 2010, at 2:25 AM, Stefan Behnel wrote:
>>> One thing that strikes me: Is "new" a keyword now?
>>
>> "new" was chosen because of the symmetry between new and del (if one
>> allocates, one needs to delete), and it would be easy for C++ people
>> to understand. Calling the constructor directly returns an object by
>> value, not a heap allocated one. (How to best handle objects returned
>> by value is an open question...) Note that the lack of block-level
>> scoping, and the c89/MSVC requirement of pre-declaring all variables
>> at the top, makes stack allocated C classes a stickier problem,
>> necessitating good support for new.
>
> But could someone please clarify explicitly whether the following
> (trivial, no fancy non-Python features) code will work in the C++
> branch?
>
> def new(x):
> return myobj(x)
> foo = new(1)
>
> ? Note that this would fail to compile if the function were named "if"
> or "cdef", etc., but with the name "new" it is currently legal.
This will still be legal--I'll even make sure there's a regression
test for it.
>> How would cython.new be used to invoke a constructor?
>>
>> cdef extern from "a.h":
>> cdef cppclass A:
>> A(int, int)
>>
>> cdef *A = cython.new(A(2,3)) #?
>
> -1
>
>> cdef *A = cython.new(A, 2, 3) #?
>
> +0
>
>>> Or is it only enabled when compiling C++
>>> code? That would be bad enough, but would at least make it less
>>> likely to
>>> break code.
>>
>> I think this is an easy issue to work around--the original grammar
>> would prohibit new as an identifier in this context anyway.
>
> Can you give more details on what you mean here?
There's no way to interpret the expression
new A(1,10)
as valid Python, so there's no ambiguity.
- Robert
_______________________________________________
Cython-dev mailing list
[email protected]
http://codespeak.net/mailman/listinfo/cython-dev
