Menu
Search

Forums

Forum Index

Thread overview
Example for multi level template composition
Oct 10, 2022
Arun
Oct 10, 2022
user1234
Oct 10, 2022
rassoc
Oct 10, 2022
ag0aep6g
Oct 11, 2022
surlymoor
October 10, 2022
Gravatar of ArunPosted by ArunReply
Arun
Gravatar of Arun


Reply

Stumbled upon this question on HN https://news.ycombinator.com/item?id=33142751#33147401

>

Can I write template A and then apply it to itself to get template B and then apply that onto template C to get template D.

Does anyone have an example for this?

October 10, 2022
Gravatar of user1234Posted by user1234
in reply to Arun		Reply
user1234
Gravatar of user1234
Posted in reply to Arun


Reply

On Monday, 10 October 2022 at 06:30:05 UTC, Arun wrote:

>

Stumbled upon this question on HN https://news.ycombinator.com/item?id=33142751#33147401

>

Can I write template A and then apply it to itself to get template B and then apply that onto template C to get template D.

Does anyone have an example for this?

Recursive templates can make other templates with themselves. I dont feel to provide an example ATM tho.

October 10, 2022
Gravatar of rassocPosted by rassoc
in reply to Arun		Reply
rassoc
Gravatar of rassoc
Posted in reply to Arun


Reply
On 10/10/22 08:30, Arun via Digitalmars-d-learn wrote:
> Stumbled upon this question on HN https://news.ycombinator.com/item?id=33142751#33147401
> 
>> Can I write template A and then apply it to itself to get template B and then apply that onto template C to get template D.
> 
> Does anyone have an example for this?

Aren't UFCS chained range calls just that?

range.map!foo.filter!bar.fold!baz;

These templates return new template ranges that transform themselves according to their inputs via Design by Introspection. For example, joiner of joiner of joiner would allow you to lazily flatten a multi dim array.
October 10, 2022
Gravatar of ag0aep6gPosted by ag0aep6g
in reply to Arun		Reply
ag0aep6g
Gravatar of ag0aep6g
Posted in reply to Arun


Reply

On Monday, 10 October 2022 at 06:30:05 UTC, Arun wrote:

>

Stumbled upon this question on HN https://news.ycombinator.com/item?id=33142751#33147401

>

Can I write template A and then apply it to itself to get template B and then apply that onto template C to get template D.

Does anyone have an example for this?

You can just write that down in code:

template D() { enum D = "It's me, template D!"; }

template A(alias MyA)
{
    template A(alias MyC)
    {
        alias A = D;
    }
}

template C() {}

alias B = A!A;
alias MaybeD = B!C;
pragma(msg, MaybeD!()); /* prints "It's me, template D!" */
October 11, 2022
Gravatar of surlymoorPosted by surlymoor
in reply to Arun		Reply
surlymoor
Gravatar of surlymoor
Posted in reply to Arun


Reply

On Monday, 10 October 2022 at 06:30:05 UTC, Arun wrote:

>

Stumbled upon this question on HN https://news.ycombinator.com/item?id=33142751#33147401

This guy could have read std.meta's documentation or source, but instead makes assumptions and lazes around.