On Fri, 30 Jul 2010 19:41:03 -0400, Justin Spahr-Summers
<[email protected]> wrote:
On Fri, 30 Jul 2010 16:30:17 -0700, Jonathan M Davis
<[email protected]> wrote:
On Friday, July 30, 2010 14:13:15 dcoder wrote:
> If I'm writing a program that pretty prints tree data, or output of
sql,
> like Oracle's sqlplus, or postgres equivalent, I find having such a
> utility function/constructor a pretty handy feature.
>
> I don't know where such a tool should finally be placed in D, but I
having
> it available as a library or as part of the language would be great.
It
> seems like a lot of other languages have it like python, perl, C++,
and
> Java. So it can't be that useless.
Well, I certainly have no problem with a function like makeArray()
existing.
It's just that it's one of those functions that I've never found
useful, and I
don't think that I've ever seen anyone use it in code.
That's because it's not a trivial function to write :) One has to have
intimate knowledge of the runtime and understand how to properly allocate
a block for this purpose.
Basically, there have been code instances of the form:
T[] x = new T[n];
x[] = initval;
Because that's the only way to do it. Offer a function like makeArray,
and why *wouldn't* you change to it? I prefer a single
line/initialization anyways.
I agree with this sentiment. I think the feature is pretty niche to
begin with, and the compiler should be able to optimize out the
initialization in the sample I gave previously. D is indeed a systems
language, but I (and I'm sure others) would like to use it in a high-
level way, where I can write natural, straightforward code and expect
the compiler to do the Right Thing.
I just find the syntax awkward:
char[] divider = new char[5]; // hey, compiler I'm initializing divider
divider[] = '-'; // OOHHH got you there, I wasn't done yet :)
It just seems natural that I should be able to do this in one line.
Having the compiler optimize isn't a bad thing, but relying on the
optimization because "we can't find a better way" seems crappy to me.
Besides, performance is not an applicable argument for this use case.
Even if the array initialization is compiled into the binary, the amount
of time it would take is infinitesimal. If someone's trying to
initialize a 100,000 element array to some specific value, they're
likely going to write their own makeArray() anyways.
The performance improvement is certainly a smaller argument compared to
the syntax. But it is a nice bonus. There are more significant
performance bugs in initialization of static arrays using array literals.
-Steve
