Hi Robert,
On 2014-05-14, Robert Bradshaw <rober...@math.washington.edu> wrote:
> Another option is to do code generation, e.g. with one of the (many)
> Python templating libraries out there.
You mean some program will write Cython code for me, Cython will
write C code for me, and gcc will do the rest? Has this approach been
used in Sage before?
Perhaps related with this: One could create a collection of "templated"
cpdef functions, using fused types (see below), and then have a metaclass,
that puts the appropriate specialisation of the cpdef functions into a
Python class' dict.
The following may be similar. Do you think that the approach makes sense?
It is what I have outlined at #15820, and produces something like methods
whose implementation is indexed by an extenion class (and is something
that a metaclass would doubtlessly be able to do automatically):
cdef class Bar_int
cdef class Bar_str
cdef fused Bar:
Bar_int
Bar_str
def foo_(Bar self):
<code that is special-cased for Bar_int and Bar_str.
It is even able to access cdef attributes of Bar_int and Bar_str
as the .data attribute below!>
cdef class Bar_str:
cdef str data
foo = foo_[Bar_str]
cdef class Bar_int:
cdef int data
foo = foo_[Bar_int]
Then, if you have an instance b of either Bar_int or Bar_str then b.foo()
calls the version of foo_ that belongs to the respective class.
Problems:
- Defining "cpdef Bar foo_(Bar self)" is possible, but then there is
an error in the line "foo = foo_[Bar_...]". Why? I thought that a cpdef
function can be treated as a Python object?
- The code above puts foo_ into Bar_int.__dict__['foo']. Do you see a
way to put it into a c(p)def attribute rather than into the class' dict?
- Note that above I assign the "templated" function named "foo_" to an
attribute named "foo". Unfortunately, it seems impossible to give both
the same name: "foo_ = foo_[Bar_int]" fails with the complaint that
Bar_int has no attribute "foo_" (well, of course it hasn't, I just try
to create such attribute!)
Best regards,
Simon
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