On Dec 12, 2007 2:11 AM, amit [EMAIL PROTECTED] wrote:
Support for generic classes
---IronPythonic way-
from System.Collections.Generic import *
l = List[str]()
l.Add(Hello)
l.Add(Hi)
l.Add(3)# fails with ValueError:
d = Dictionary[str, int]()
d.Add('abc', 1)
d.Add('def', 2)
for i in d.Keys:
print d[i]
So here in pypy-clr what we'd like to do is
import System.Collections.Generic.LinkedListstr
we can't use this syntax, because the parser would complain. We need
to use the same trick as IronPython, i.e. use square brackets.
l= System.Collections.Generic.LinkedListstr()
l.Add(hello)
l.Add(hi)
l.Add(3)# throw ValueError exception
the import is to be analysed if its an import for a Generic Class and
loaded as
clr.load_cli_generic_class('System.Collections.Generic','LinkedListstr')
No, I don't think we want to do so. I think the best is to mimic
IronPython as much as possible. I.e., let the user to import the
generic class by itself, e.g. import
System.Collections.Generic.List; then, if you do List[str] it
returns a concrete class that can be istantiated as in IronPython.
The implementation of load_cli_generic_class is a BlackBox to me as of now.
From the import line we can check if the class is a generic and then
reflection can be used to determine:
a) Generic type
b) type arguments
c) Parameter attributes
and more
I hope somehow the existing build_wrapper could be used after putting
some checks but I am not sure how.
well, basically you have to check whether a class is generic; if it
is, we need to construct it by using another metaclass which has
support for __getitem__; something like this:
class MetaGenericCliClassWrapper(...):
def __getitem__(self, *types):
# do something
return load_cli_class(...)
But before you can use this metaclass, you need to ensure that
load_cli_class works fine with concrete instantiations of generic
classes. So, the first thing to do is to write a test like this:
def test_generic_class(self):
ListInt = load_cli_class(System.Collections.Generic, List`1int32)
x = ListInt()
x.Add(42)
# etc...
Then we need to write other tests for the error cases (e.g., test that
if you put a string inside x it raises ValueError).
Maybe these test swould work out of the box, I don't know. After that,
all we need to do is to provide some nice syntactic sugar like square
brackets co.
ciao Anto
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