Extend generic types

[Charles]

I have implemented generic type extensions. That is, you can now "extend" on a generic type such as IList<of T>.

Quick example:

extend Dictionary<of TKey, TValue>

    def lastValue as TValue
        keys = List<of TKey>(.keys)
        keys.sort
        return this[keys[keys.count-1]]


class P

    def main is shared

        d = {
            'a': 1,
            'b': 2,
            'z': 3,
            'c': 4,
            'd': 5,
        }
        
        assert d.lastValue == 3

You can browse the test cases in your local workspace or online at http://cobra-language.com/trac/cobra/browser/cobra/trunk/Tests/420-extensions/400-extend-generics.

This feature will enable us to add convenience methods to IList, IDictionary, etc.

If you find any problems, please report them here.

[gauthier]

that's looking handy

as for .net extension methods, do you plan to support C# 3 extension method call and definition soon?

def transform(this text as String) as String is shared
    return text + text

[Charles]

If you mean syntaxwise, no. The Cobra syntax is already established as:

extend String
    def transform as String
        return this + this

If you mean translating Cobra's extensions down to the C# syntax so that C# 3 programs see them properly, yes we would do that as part of supporting .NET 3.5+. Same with reading C#/VB extensions from .DLLs.

But right now Cobra is still on .NET 2.0 and I haven't given much thought to moving to later versions of .NET.