Lambda the Ultimate

activeTopic Adding Wildcards to Java
started 6/14/2004; 11:20:49 AM - last post 6/14/2004; 12:44:45 PM
Isaac Gouy - Adding Wildcards to Java  blueArrow
6/14/2004; 11:20:49 AM (reads: 72, responses: 4)
Adding Wildcards to the Java Programming Language
"Based on the notion of use-site variance, wildcards provide a type safe abstraction over different instantiations of parameterized classes, by using ? to denote unspecified type arguments. Thus they essentially unify the distinct families of classes often introduced by parametric polymorphism."

Chris Rathman - Re: Adding Wildcards to Java  blueArrow
6/14/2004; 11:40:10 AM (reads: 66, responses: 1)
In glancing through the paper, it mostly brings to mind Constrained Genericity that is used in Eiffel. If that be the case, I think using a wildcard character (out of regular expressions bag) is more confusing than enlightening.

(not sure if Meyer lifted the idea from Ada?).

Ehud Lamm - Re: Adding Wildcards to Java  blueArrow
6/14/2004; 12:03:18 PM (reads: 62, responses: 0)
(not sure if Meyer lifted the idea from Ada?)

I don't know. Meyer likes to mock Ada's OOP, but Ada83 genericity was quite advanced for its time.

Chris Rathman - Re: Adding Wildcards to Java  blueArrow
6/14/2004; 12:21:46 PM (reads: 59, responses: 1)
Was thinking more along the lines of Ada generics. Can't remember if it supports constraints or not?

WRT Meyer, he had lots of good things to say about Ada (other than his dislike of the OOP stuff).

Ehud Lamm - Re: Adding Wildcards to Java  blueArrow
6/14/2004; 12:44:45 PM (reads: 53, responses: 0)
Ada generics are constrained. The Ada83 constraints aren't the same as you'd find in current OO languages, since Ada83 lacked inheritance. Ada95 added inheritance and enhanced the generic contract model accordingly.