This Week in #Dlang - new bugfix release, Windows driver, Azure+vibe tutorial, tip on uda transformations + mixin templates

http://arsdnet.net/this-week-in-d/sep-27.html


The tip here is one I've been talking about on irc a little and decided to write up this time. Using a mixin template to hold the source code of a thing to be transformed is something I think is kinda cool.... though I haven't actually used it in a real project yet. (Actually, I've barely used UDAs in the real world at all yet. I was so excited for them when they were new, but it took so long to materialize that I found other ways to do my stuff and now haven't transitioned!)

On Monday, 28 September 2015 at 13:03:50 UTC, Adam D. Ruppe wrote:
> The tip here is one I've been talking about on irc a little and decided to write up this time. Using a mixin template to hold the source code of a thing to be transformed is something I think is kinda cool.... though I haven't actually used it in a real project yet. (Actually, I've barely used UDAs in the real world at all yet. I was so excited for them when they were new, but it took so long to materialize that I found other ways to do my stuff and now haven't transitioned!)

Somewhat related to this, see page 6 of what I was working on over the weekend: https://github.com/DlangScience/design/blob/master/design.pdf

On Monday, 28 September 2015 at 13:06:37 UTC, John Colvin wrote:
> https://github.com/DlangScience/design/blob/master/design.pdf

BTW there is a plot thing David Simcha did years ago:
http://code.dlang.org/packages/plot2kill

I don't know how good it is though, I've never actually used it.

That page 6 bit is cool too, nice stuff.

On Monday, 28 September 2015 at 13:03:50 UTC, Adam D. Ruppe wrote:
> This Week in #Dlang - new bugfix release, Windows driver, Azure+vibe tutorial, tip on uda transformations + mixin templates
>
> http://arsdnet.net/this-week-in-d/sep-27.html
>
>
> The tip here is one I've been talking about on irc a little and decided to write up this time. Using a mixin template to hold the source code of a thing to be transformed is something I think is kinda cool.... though I haven't actually used it in a real project yet. (Actually, I've barely used UDAs in the real world at all yet. I was so excited for them when they were new, but it took so long to materialize that I found other ways to do my stuff and now haven't transitioned!)

Really cool trick. I had to run it and look at the output to really understand though!

Atila

On 2015-09-28 15:03, Adam D. Ruppe wrote:

> The tip here is one I've been talking about on irc a little and decided
> to write up this time. Using a mixin template to hold the source code of
> a thing to be transformed is something I think is kinda cool.... though
> I haven't actually used it in a real project yet. (Actually, I've barely
> used UDAs in the real world at all yet. I was so excited for them when
> they were new, but it took so long to materialize that I found other
> ways to do my stuff and now haven't transitioned!)

This looks pretty cool. Unfortunately the original code needs to be contained inside a template :( .

-- 
/Jacob Carlborg

On Tuesday, 29 September 2015 at 07:09:35 UTC, Jacob Carlborg wrote:
> This looks pretty cool. Unfortunately the original code needs to be contained inside a template :( .

Yeah. You could put it in a module too (my original plan was to write about "module mything_impl; code here" and "module mything; mixin magic_from_mything_impl;" but there's a bit more difficulty with that and forwarding all members you don't want to transform.

Though, I just had an idea on how that might be simplified.... don't recreate them, just alias them!



So, conceptually, you'd do something like:


template transformer(alias member) {
    static if(hasUDA!(member, thing))
        mixin(transformed_version_of_member());
    else
        alias member = member;
}
mixin staticMap!(AllMembers!impl_module, transformer);



So you bring in the original thing via alias in much the same way I brought it in via template mixin, then do the rest basically the same.


That *should* work and not even be all that much more code. Then you don't need to wrap anymore. Though it does still need to be in a separate something, whether input module or struct, from the output.

On 2015-09-29 14:10, Adam D. Ruppe wrote:

> Though, I just had an idea on how that might be simplified.... don't
> recreate them, just alias them!
>
>
>
> So, conceptually, you'd do something like:
>
>
> template transformer(alias member) {
>      static if(hasUDA!(member, thing))
>          mixin(transformed_version_of_member());
>      else
>          alias member = member;
> }
> mixin staticMap!(AllMembers!impl_module, transformer);

This looks even more interesting :)

-- 
/Jacob Carlborg