What are some features that you have discovered that you would like to share with the community? For me, one thing I found interesting was the ability to define structures dynamically using mixins:

import std.stdio;
import std.format: format;

template MakePoint(string name, string x, string y) {
    const char[] MakePoint = "struct %s {int %s; int %s;}".format(name, x, y);
}

mixin(MakePoint!("Point", "x", "y"));

void main() {
    auto pt = new Point;
    pt.x = 1;
    pt.y = 2;
    writefln("point at (%s, %s)", pt.x, pt.y);
}

On Wednesday, 12 April 2017 at 21:40:48 UTC, bluecat wrote:
> What are some features that you have discovered that you would like to share with the community? For me, one thing I found interesting was the ability to define structures dynamically using mixins:
>
> import std.stdio;
> import std.format: format;
>
> template MakePoint(string name, string x, string y) {
>     const char[] MakePoint = "struct %s {int %s; int %s;}".format(name, x, y);
> }
>
> mixin(MakePoint!("Point", "x", "y"));
>
> void main() {
>     auto pt = new Point;
>     pt.x = 1;
>     pt.y = 2;
>     writefln("point at (%s, %s)", pt.x, pt.y);
> }

this one does not need to be a template.
You can build the string using ctfe which is much faster indeed.

On Wednesday, 12 April 2017 at 21:40:48 UTC, bluecat wrote:
> What are some features that you have discovered that you would like to share with the community?

auto use(alias F, T)(T t){return F(t);}

void main()
{   import std.stdio;
    foreach(i; 1 .. 11)
    {   foreach(j; 1 .. 11) write((i * j).use!(x => x*x), " ");
        writeln;
    }
}

This way, you can avoid writing long expressions twice with UFCS.

On Wednesday, 12 April 2017 at 21:40:48 UTC, bluecat wrote:
> What are some features that you have discovered that you would like to share with the community? For me, one thing I found interesting was the ability to define structures dynamically using mixins:
>
> import std.stdio;
> import std.format: format;
>
> template MakePoint(string name, string x, string y) {
>     const char[] MakePoint = "struct %s {int %s; int %s;}".format(name, x, y);
> }
>
> mixin(MakePoint!("Point", "x", "y"));
>
> void main() {
>     auto pt = new Point;
>     pt.x = 1;
>     pt.y = 2;
>     writefln("point at (%s, %s)", pt.x, pt.y);
> }

There are quite a few in https://p0nce.github.io/d-idioms/
and This Week in D: http://arsdnet.net/this-week-in-d/

On Thursday, 13 April 2017 at 05:51:27 UTC, Dukc wrote:
> auto use(alias F, T)(T t){return F(t);}
>
> void main()
> {   import std.stdio;
>     foreach(i; 1 .. 11)
>     {   foreach(j; 1 .. 11) write((i * j).use!(x => x*x), " ");
>         writeln;
>     }
> }
>
> This way, you can avoid writing long expressions twice with UFCS.
If fact you don't need any template to do this. Try the next:

    foreach(i; 1 .. 11)
    {   foreach(j; 1 .. 11) write((x => x*x)(i * j), " ");
        writeln;
    }

On Wednesday, 12 April 2017 at 21:40:48 UTC, bluecat wrote:
> What are some features that you have discovered that you would like to share with the community? For me, one thing I found interesting was the ability to define structures dynamically using mixins:
>
> import std.stdio;
> import std.format: format;
>
> template MakePoint(string name, string x, string y) {
>     const char[] MakePoint = "struct %s {int %s; int %s;}".format(name, x, y);
> }
>
> mixin(MakePoint!("Point", "x", "y"));
>
> void main() {
>     auto pt = new Point;
>     pt.x = 1;
>     pt.y = 2;
>     writefln("point at (%s, %s)", pt.x, pt.y);
> }

I really like the ability to pass delegates as `alias` template arguments. This allows me to pass these delegates as templates, and the "higher-order" template can instantiate them multiple times with multiple types: https://dpaste.dzfl.pl/e2a7a252b5cc

On Thursday, 13 April 2017 at 11:16:46 UTC, crimaniak wrote:
> On Thursday, 13 April 2017 at 05:51:27 UTC, Dukc wrote:
>> auto use(alias F, T)(T t){return F(t);}
>>
>> void main()
>> {   import std.stdio;
>>     foreach(i; 1 .. 11)
>>     {   foreach(j; 1 .. 11) write((i * j).use!(x => x*x), " ");
>>         writeln;
>>     }
>> }
>>
>> This way, you can avoid writing long expressions twice with UFCS.
> If fact you don't need any template to do this. Try the next:
>
>     foreach(i; 1 .. 11)
>     {   foreach(j; 1 .. 11) write((x => x*x)(i * j), " ");
>         writeln;
>     }

Thats a good one, wrote that down for next time. With that I'll share another one I read about that I thought was really cool:

import std.stdio;
import std.functional: memoize;

ulong fib(ulong n) {
    alias mfib = memoize!(fib);
    return n < 2 ? 1 : mfib(n-2) + mfib(n-1);
}

void main() {
    foreach (x; 1..45) {
        writefln("%s", x.fib);
    }
}

What this does is make calculating the recursive fibonacci sequence much faster. I don't know too much about the technique, but having it in my optimizations.txt is always a good thing. Now that I think of it, I wonder if there is a page on this website that lists common optimization techniques.

On Thursday, 13 April 2017 at 11:16:46 UTC, crimaniak wrote:
> If fact you don't need any template to do this. Try the next:
>
>     foreach(i; 1 .. 11)
>     {   foreach(j; 1 .. 11) write((x => x*x)(i * j), " ");
>         writeln;
>     }

True, that's a good trick too. But I prefer the template at least sometimes because I ususally construct the argument up first and only then start to think about what function to call. With the use template, I can write and read in order I think -Exactly the reason why UFCS rules in my opinion.

On Thursday, 13 April 2017 at 05:51:27 UTC, Dukc wrote:
> auto use(alias F, T)(T t){return F(t);}
>
> void main()
> {   import std.stdio;
>     foreach(i; 1 .. 11)
>     {   foreach(j; 1 .. 11) write((i * j).use!(x => x*x), " ");
>         writeln;
>     }
> }

forgot three letters:

auto use(alias F, T...)(T t){return F(t);}

to make it work with many arguments:

void main()
{   import std.stdio;
    foreach(i; 1 .. 11)
    {   foreach(j; 1 .. 11) write((i * j).use!((x, y) => x^^y)(2), " ");
        writeln;
    }
}