Re: Idioms you use
On 10/05/15 17:53, Marco Leise via Digitalmars-d wrote: > Am Sun, 04 Oct 2015 00:08:39 +0200 > schrieb Artur Skawina via Digitalmars-d > : > >>static ctfe = ctfeArr!( iota(256).map!isDigit() ); >> >>immutable typeof(R.front)[R.array().length] ctfeArr(alias R) = R.array(); > > I like that. Also that 1) In D everything is possible. And 2) > If not, there is a workaround, goto 1). Note that I just wanted to show that the ctfeArr /function/ was not necessary, and I didn't want that `ctfe` declaration to be affected; real code would look more like: enum typeof(R.front)[R.array().length] ctfeArr(alias R) = R.array(); immutable ctfe = ctfeArr!( iota(256).map!isDigit() ); artur
Re: Idioms you use
Am Sun, 04 Oct 2015 00:08:39 +0200 schrieb Artur Skawina via Digitalmars-d : >static ctfe = ctfeArr!( iota(256).map!isDigit() ); > >immutable typeof(R.front)[R.array().length] ctfeArr(alias R) = R.array(); I like that. Also that 1) In D everything is possible. And 2) If not, there is a workaround, goto 1). -- Marco
Re: Idioms you use
On 10/03/15 15:53, Marco Leise via Digitalmars-d wrote:
> Am Mon, 28 Sep 2015 21:40:43 +
> schrieb Freddy :
>
>> Are any D idioms you use that you like to share?
>> Heres one of mine
>> ---
>> enum ctfe =
>> {
>> return 0xdead & 0xbad;
>> }();
>> ---
>
> Yep, using that often, although I try to get my head around
> using functional style one-line expressions where possible to
> avoid the boilerplate.
>
> static immutable ctfe = {
> bool[256] result;
> foreach (i; 0 .. 256)
> result = isDigit(i);
> return result;
> }();
>
> ==>
>
> static immutable bool[256] ctfe = iota(256).map!isDigit.array;
>
> ==>
>
> static ctfe = ctfeArr!( iota(256).map!isDigit );
>
> enum ctfeArr(alias r)()
> {
> // r.length doesn't work as static array size
> enum length = r.length;
> // immutable doesn't work on this (cannot modify const)
> ElementType!(typeof(r))[length] result = r.array;
> // Cross fingers here ...
> return cast(immutable) result;
> }
==>
static ctfe = ctfeArr!( iota(256).map!isDigit() );
immutable typeof(R.front)[R.array().length] ctfeArr(alias R) = R.array();
[`array` is only required because of compiler issues, yes.]
artur
Re: Idioms you use
Am Mon, 28 Sep 2015 21:40:43 +
schrieb Freddy :
> Are any D idioms you use that you like to share?
> Heres one of mine
> ---
> enum ctfe =
> {
> return 0xdead & 0xbad;
> }();
> ---
Yep, using that often, although I try to get my head around
using functional style one-line expressions where possible to
avoid the boilerplate.
static immutable ctfe = {
bool[256] result;
foreach (i; 0 .. 256)
result = isDigit(i);
return result;
}();
==>
static immutable bool[256] ctfe = iota(256).map!isDigit.array;
==>
static ctfe = ctfeArr!( iota(256).map!isDigit );
enum ctfeArr(alias r)()
{
// r.length doesn't work as static array size
enum length = r.length;
// immutable doesn't work on this (cannot modify const)
ElementType!(typeof(r))[length] result = r.array;
// Cross fingers here ...
return cast(immutable) result;
}
--
Marco
Re: Idioms you use
On Tuesday 29 September 2015 15:06, Cauterite wrote: > some statements Buf of course! I totally didn't think of multiple statements. Thanks.
Re: Idioms you use
On Tuesday, 29 September 2015 at 12:52:36 UTC, anonymous wrote:
Why not just `enum ctfe = 0xdead & 0xbad;`?
Are there cases where `enum foo = {return bar;}();` works but
`enum foo = bar;` doesn't? And if there are, aren't they
compiler bugs?
I'm pretty sure he's talking about the general use of an
anonymous function invocation assigned to an enum to force some
statements to be executed at compile time. His example was not
very illustrative though.
Re: Idioms you use
On Tuesday, 29 September 2015 at 12:52:36 UTC, anonymous wrote:
Are there cases where `enum foo = {return bar;}();` works but
`enum foo = bar;` doesn't? And if there are, aren't they
compiler bugs?
If it is more complex than just one statement, putting it in a
function lets you execute multiple lines (including loops and
stuff) at once.
Re: Idioms you use
On Monday 28 September 2015 23:40, Freddy wrote:
> Are any D idioms you use that you like to share?
> Heres one of mine
> ---
> enum ctfe =
> {
> return 0xdead & 0xbad;
> }();
> ---
Why not just `enum ctfe = 0xdead & 0xbad;`?
Are there cases where `enum foo = {return bar;}();` works but `enum foo =
bar;` doesn't? And if there are, aren't they compiler bugs?
Re: Idioms you use
On Monday, 28 September 2015 at 21:40:45 UTC, Freddy wrote: Are any D idioms you use that you like to share? I'm not sure if these fit under the definition of 'idiom', but they sort of are… I think. http://dpaste.dzfl.pl/f66a76a7411f You could even extend the concept with opDispatch to achieve syntax like this: pinvoke.psapi.GetProcessImageFileNameW!uint(...); I've used a similar technique (+ caching) to lazily load OpenGL extensions. It worked really well.
Re: Idioms you use
On Monday, 28 September 2015 at 21:40:45 UTC, Freddy wrote:
Are any D idioms you use that you like to share?
Heres one of mine
---
enum ctfe =
{
return 0xdead & 0xbad;
}();
---
What does this do and where would it be useful in my code?
For D idioms I usually go here...you may want to submit a PR:
http://p0nce.github.io/d-idioms/
Phobos is another good source of how to do X in D.
bye,
lobo
