Hi all,

I'm looking for the equivalent of `typeof(this)` in module scope (so that it gets the current module). My use-case is iterating over the members of the module - right now I'm doing

`mixin(iterateOverModule!(module.name.here));`

but in the interests of keeping the code simple to maintain, I'd like to be able to get the current module automatically.

Is this possible? A cursory Google search didn't turn up anything, and `this` has no meaning in module scope.

On Tuesday, 12 April 2016 at 13:44:07 UTC, Mithun Hunsur wrote:
> I'm looking for the equivalent of `typeof(this)` in module scope (so that it gets the current module).

The trick I use is `mixin(__MODULE__)`.

I also mentioned this in my book

https://www.packtpub.com/application-development/d-cookbook

the free sample is the reflection chapter which has a few tricks like this.

On Tuesday, 12 April 2016 at 14:22:22 UTC, Adam D. Ruppe wrote:
> On Tuesday, 12 April 2016 at 13:44:07 UTC, Mithun Hunsur wrote:
>> I'm looking for the equivalent of `typeof(this)` in module scope (so that it gets the current module).
>
> The trick I use is `mixin(__MODULE__)`.
>
> I also mentioned this in my book
>
> https://www.packtpub.com/application-development/d-cookbook
>
> the free sample is the reflection chapter which has a few tricks like this.

Thanks! That works great. For anyone else stumbling across this in the future: if your mixin is in another file, you need to pass in __MODULE__ as a default argument:

mixin template ATemplate(string moduleName = __module__)
{
    mixin(moduleName); // Is a reference to the module that instantiated it.
}

This can be a little finicky, so I'd still like to see language-level support for getting the current module (perhaps defining 'this' at module-level to be the current module). I'll probably make a post in the main group for it - thanks for the help :)

On Tuesday, 12 April 2016 at 13:44:07 UTC, Mithun Hunsur wrote:
> Hi all,
>
> I'm looking for the equivalent of `typeof(this)` in module scope (so that it gets the current module). My use-case is iterating over the members of the module - right now I'm doing
>
> `mixin(iterateOverModule!(module.name.here));`
>
> but in the interests of keeping the code simple to maintain, I'd like to be able to get the current module automatically.
>
> Is this possible? A cursory Google search didn't turn up anything, and `this` has no meaning in module scope.

Have you tried __traits(parent, someTopLevelSymbol)?

Walking the __traits(parent) chain should get you to a module either way, I think.

On Wednesday, 13 April 2016 at 05:30:27 UTC, Vladimir Panteleev wrote:
> On Tuesday, 12 April 2016 at 13:44:07 UTC, Mithun Hunsur wrote:
>> Hi all,
>>
>> I'm looking for the equivalent of `typeof(this)` in module scope (so that it gets the current module). My use-case is iterating over the members of the module - right now I'm doing
>>
>> `mixin(iterateOverModule!(module.name.here));`
>>
>> but in the interests of keeping the code simple to maintain, I'd like to be able to get the current module automatically.
>>
>> Is this possible? A cursory Google search didn't turn up anything, and `this` has no meaning in module scope.
>
> Have you tried __traits(parent, someTopLevelSymbol)?
>
> Walking the __traits(parent) chain should get you to a module either way, I think.

Yeah, that also works; you have to define a symbol (if you don't have one you can already use) in order to get to it, so it's a little wasteful. Still useful to know, though!

On Wednesday, 13 April 2016 at 11:36:07 UTC, Mithun Hunsur wrote:
> Yeah, that also works; you have to define a symbol (if you don't have one you can already use) in order to get to it, so it's a little wasteful. Still useful to know, though!

No, it's not necessary. You should be able to walk the chain of __traits(parent) by starting with a local symbol, e.g. a lambda predicate.

Have a look at std.traits.moduleName which does most of the work.

On Wednesday, 13 April 2016 at 16:58:34 UTC, Vladimir Panteleev wrote:
> On Wednesday, 13 April 2016 at 11:36:07 UTC, Mithun Hunsur wrote:
>> Yeah, that also works; you have to define a symbol (if you don't have one you can already use) in order to get to it, so it's a little wasteful. Still useful to know, though!
>
> No, it's not necessary. You should be able to walk the chain of __traits(parent) by starting with a local symbol, e.g. a lambda predicate.
>
> Have a look at std.traits.moduleName which does most of the work.

Aha! That is a _very_ clever trick. :) For everyone else:

__traits(parent, {});

The {} is a lambda predicate instantiated in the current scope (i.e. module scope); getting the parent of that gets you the module. If you wanted to generalise that, you could walk up the parent chain like Vladimir says - but this is perfect for my uses. Thanks again!