New

[Pavel Minaev]

On Mon, Mar 29, 2010 at 10:11 PM, Paul Benedict <pbenedict at apache.org> wrote:
> On Mon, Mar 29, 2010 at 8:51 PM, Howard Lovatt <howard.lovatt at gmail.com> wrote:
>> I think the strongest argument that anyone has made against using 'new' is
>> your "economy of expression" argument, it then comes down to trading off
>> conciseness against consistency and clarity. I go with consistency and
>> clarity and you go with conciseness. I guess Alex or someone at Sun will
>> decide :)
>
> At one time, the "lambda" keyword was thrown around as an option. Any
> thoughts to floating that idea around again? I suppose it was supposed
> to function in the language like the "new" keyword:
>
> #<int()> foo = lambda #<int()>(42);

If you already have # there, then "lambda" serves no purpose
whatsoever. # alone is enough to indicate the start of the lambda.

If you don't use #, then you have to add it as a new reserved keyword
- meaning that any existing Java code which uses "lambda" as
identifier won't compile anymore. Nor can you make it an unambiguous
context keyword, because, when generics are involved, you can get
something like:

   lambda <A<B>(C<D> e)> (e + 1)

which is a perfectly valid expression as far as they go:

  (((lambda < A) < B) > ((C < D) > e)) > (e + 1)

Of course, it'll never type-check, but that doesn't stop it from being
valid grammar for an expression, which is enough to confuse the
parser.