Proposal: Sameness operators

Tom Hawtin Thomas.Hawtin at Sun.COM
Wed Apr 1 11:26:43 PDT 2009

Christian Fischer wrote:
> These $-operators doesn't seem intuitive to me, but replacing equal-calls
> sounds interesting.
> Maybe a better solution would be something like this:
> if (a eq b) // equals
> if (a ne b) // not equal
> if (a lt b) // lesser than
> if (a le b) // lesser or equal

Along with other concerns, four new keywords?! Theoretically they could 
be context sensitive, but then we are boxing in the grammar.

If something like this were to be done (and let's face it, operator 
overloading ain't gonna happen in JDK7), then I think there needs to be 
to changes in fundamental direction of the proposal.

  * We need new symbols. .<. and the like were proposed in another 
similar proposal. So long as the symbol is a sequence of characters 
which is not valid in an existing Java program (outside of comments and 
literal strings).

  * I think it's clear that we can't use Comparable.compareTo and 
Object.equals. It requires a new method for each operator.


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