Static typing (was Re: Java guy interested in Python)

[Hamish Lawson]

Michael Hudson wrote:

> If you type-annotate this, you might write (using entirely made up
> syntax):
> 
> def write16(file : <file>, int : <int>):
>     file.write(struct.pack("h",int))
> 
> but then what about passing in a StringIO object, or some user 
> wrapper of a file object?  What makes a "<file>"?  At the moment, 
> it's just a loose collection of methods, some of which are optional 
> in some circumstances.

Wouldn't there be a hierarchy of interface types for file-like objects,
with some interfaces specifying more methods than others? You'd then
choose the interface type that specified the collection of methods that
you require of your passed object.

Not-that-I'd-necessarily-want-this-all-of-the-time-ly yours,
Hamish Lawson


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