Re: Re: pattern matching on fields of the argument

>>operator-overloding to use any operator for this meaning, given that
>>type expressions are becoming first-class (in the CVS version
>>fully-qualified types are, and I think I will generalize it to others
>>too).
> 
> 
> Like Cayenne?

No, it's not a fundamental change in the type system. It's the idea that types 
can appear in the syntax anywhere an expression is expected. These type 
expressions denote a java.lang.Class at runtime, and they can also be used 
with operators that expects a type, like instanceof. So you could write an 
operator that does the same thing as instanceof:

   <T,U> boolean `/` (T value, Class<U> type) = `instanceof`(value, type);

and use it like:

   InputStream x = ...;
   if (x/java.io.BufferedInputStream)
     {...}


Something that could make it to nice.lang would be a version of cast where you 
can specify the target type. It can now be implemented in pure Nice:

   <T, U> U cast(T value, Class<U> type) = cast(value);

That's mostly redundant when you assign to a local variable (since you can 
declare its type), but is useful when using directly inside a complex 
expression. Not sure if we should encourage that or not.

Cheers,

Daniel


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