On Dec 12, 2007 2:11 AM, amit <regmi.amit@gmail.com> 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.LinkedList<str>

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.LinkedList<str>() 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','LinkedList<str>')

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`1<int32>") 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