Closures, too much or too little?

[tronicek at fit.cvut.cz]

> @For
>     @ForInit int x = 10;
>     @ForCond x < 20;
>     @ForIncr x++;
> @ForBlock {
> }

This approach would have been ok, if Java was designed with annotations
instead of keywords. But it was not. And so it is, in my opinion, against
the spirit of the language.

Z.
-- 
Zdenek Tronicek
FIT CTU in Prague
http://kenai.com/projects/refactoringng - refactoring tool for compiler guys


Reinier Zwitserloot napsal(a):
> Aside from your other arguments, why would a language have 2 separate
> constructs for what boils down to doing mostly the same thing?
>
> Convenience of course. Annotations are parameterized, pluggable, and have
> their own namespace, and even need to be imported. Keywords have none of
> those things, but they are independent of libraries, appear in entirely
> different places, and are easier to type. Unless you find:
>
> @For
>     @ForInit int x = 10;
>     @ForCond x < 20;
>     @ForIncr x++;
> @ForBlock {
> }
>
> easier to read than for (int x = 10; x < 20; x++) {}, of course.
>
> --Reinier Zwitserloot
>
>
>
> On Mon, Nov 23, 2009 at 1:51 PM, <tronicek at fit.cvut.cz> wrote:
>
>> Hi Howard,
>>
>> I do not understand your arguments. Warning means "be cautious, there
>> may
>> be an error" and error means "there is an error".
>> The @Shared annotation says "be cautious, the variable will be shared
>> between threads". This warning makes sense because we (programmers) are
>> not used to sharing the local variables.
>> However, it does not mean anything on the bytecode level. That is, the
>> program is compiled the same way regardless of the annotation. So what
>> error you want to report?
>>
>> > I also find the advise that annotations don't change program behavior
>> > a little silly. Half the time your program won't even run without the
>> > correct annotations in many frameworks!
>>
>> There is a difference between the Java language and Java frameworks. If
>> you let the annotations change the semantics of the Java language, what
>> would be the difference between annotations and keywords? None, except
>> the
>> way how they are written. And does it make sense to have two language
>> categories for the same?
>> It may seem that annotations can help in adding new features. To some
>> extent, it is true. But it violates the language consistency.
>>
>> Zdenek
>> --
>> Zdenek Tronicek
>> FIT CTU in Prague
>> http://kenai.com/projects/refactoringng - refactoring tool for compiler
>> guys
>>
>>
>> Howard Lovatt napsal(a):
>> > Sure for BGGA it suppresses a warning, but there would be nothing to
>> stop
>> > inner classes been changed to the same mechanism (I think CISE
>> proposed
>> > something similar). For a library as opposed to a language feature you
>> > could
>> > change the @Shared to provide automatic wrapping in a holder. This is
>> not
>> > quite the same, in that you would get an error as opposed to a warning
>> if
>> > @Shared was absent.
>> >
>> > However, I prefer the error since I am not a fan of warning messages
>> and
>> > thought Java was better before warnings and I am therefore not fazed
>> by
>> > this. I also find the advise that annotations don't change program
>> > behavior
>> > a little silly. Half the time your program won't even run without the
>> > correct annotations in many frameworks!
>> >
>> >  -- Howard.
>> >
>> > 2009/11/22 Neal Gafter <neal at gafter.com>
>> >
>> >> On Sun, Nov 22, 2009 at 12:20 PM, Howard Lovatt
>> >> <howard.lovatt at iee.org>wrote:
>> >>
>> >>> I agree with your point that it really only captures finals (which
>> as
>> >>> you
>> >>> say are simple values of an expression in the LamdaJ 'closure'), but
>> to
>> >>> me
>> >>> this is a secondary issue. A @Shared annotation could be introduced
>> >>> that
>> >>> works with inner classes and with LamdaJ closures.
>> >>>
>> >>
>> >> @Shared in BGGA just suppresses a warning; it has no effect on the
>> >> semantics of the code.  I have no idea what specification for an
>> >> annotation
>> >> you have in mind that could affect the way lambdaj works.
>> >>
>> >> ______________________________________________________________________
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>> >>
>> >
>> >
>> >
>> > --
>> >  -- Howard.
>> >
>> >
>> >
>> > --
>> >  -- Howard.
>> >
>> >
>>
>>
>>
>