The DUB package manager

[Dmitry Olshansky]

23-Feb-2013 22:40, Russel Winder пишет:
> On Sat, 2013-02-23 at 21:44 +0400, Dmitry Olshansky wrote:
> […]
>> I have to say that no amount of provided out of the box nice libraries
>> and top-notch GC help alleviate the dire need for plain value-types and
>> some kind of terseness (rows of static final int xyz = blah; to define a
>> bunch of constants). With Java version being 5 or 6 (as is usually the
>> case in production ATM) there is basically not a single construct to
>> avoid horrible duplication of information on each line.
>
> Maybe in Java 1.4, 8 years ago a plethora of public static final int
> constants, but these days seeing that implies a bad design, a complete
> lack of updating/refactoring of the software to modern Java features, or
> simple laziness. Java 5 introduced more than generics.

Admittedly I'm no expert on Java. Hence "have to work".
Would be nice to know if there is something that can represent this C 
snippet without the usual heaps of verbosity:
enum {
STATUS_OK = 0,
STATUS_FAIL_REASON_XYZ,
... ad infinitum (but presently dozens)
};

There are lots of other cases, but this one is prime.

You might argue for using classes and inheritance + visitor pattern 
instead of plain switch/state machines. The heaps of boilerplate to 
write/generate all of "state"/visitor etc. classes argues the other way 
around.
(and I suspect the execution speed too)

>
> The G1 GC is a significant improvements to Java.

I guess this depends on the platform you (have to) use?
BTW I agree that Java's GC is nice, more so the automatic 
de-heapification of modern VMs.

>
> Java supports value types, albeit as objects on the heap. Give me an
> example of the problem so we can approach this with more than waffly
> statements.

A trivial example is storage of pairs or tuples. That plus using Java's 
containers makes memory footprint explode. At 100K+ hash-map I notice 
quite high factor of waste. It's some double digits compared to plain C 
arrays. I probably shouldn't care that much since servers are having 
tons of RAM these days, and customers throw money on equipment without 
second thought. Thus for the moment I just can't help but notice. Thank 
god we are mostly I/O bound.

Another example. I had to sort some objects by rating for a bit of 
processing with ranking. Yet this rating is computed and really doesn't 
belong with them at all (and needs locking beforehand) and I can't 
reorder them in place. What I'd do is create an array of tuple 
link-rating and sort these.

In Java I have to create a full-blown object and allocate each array 
slot separately, cool. Not to mention the complete lack of concise tuples.

Writing functors is a royal pain in the ass too. Anonymous classes 
doesn't quite cut it on the scale of verbosity/benefit. If there any 
library that doesn't use reflection like crazy to achieve simple, 
concise functors, I'd be glad to use it but so far I found none.

Sorry can't elaborate on exact details here, the work is not open-source 
by any measure.

> Far too few programmers use the final keyword properly/effectively.

In Java programs it can be used very often. I'd say too often since I 
find it rare to have a need to e.g. rebind an object. As for "a few 
programmers", well you have to type it everywhere, guess why it's not 
popular?!

>> There are few shortcuts in Java 7, and even more stuff in Java 8 but all
>> of it is coming horribly too late and doesn't fix the "big picture".
>> Plus that has to propagate into the  mainstream.
>
> This is Java's serious problem. There are still people using Java 1.4.2
> because they can't be bothered to update to Java 5 let alone 7.

And even if e.g. I for one would go for Java 7 it really doesn't depend 
on my views at all.

> […]
>
> I have many problems with Java, it is very verbose, but it needs to be
> criticized in a fair manner not in a "slag off" way. Clearly everyone on
> this list is going to prefer D over Java, but that is not permission to
> use inappropriate argumentation.

Mmm. I report my experience not argument much of anything excpet that 
it's far from pleasant.

If anything I might convince the team to switch off to Scala, someday.
If not the somewhat alien syntax it would be far easier.

-- 
Dmitry Olshansky