Re: [rust-dev] RFC: Importing/exporting macros

[Brendan Zabarauskas]

Agreed. Exporting macros feels like a hack. Importing macros feels like a hack. 
Global namespaces are a pain.

Macros on the whole feel like a second class citizen of the language. I’m not 
talking about writing them - I’m perfectly fine about that kind of ugliness – 
I’m referring to the client side usability. I would steer clear from forcing 
them on the users of my libraries.

~Brendan

On 26 Feb 2014, at 8:39 am, Sean McArthur  wrote:

> Rust now has the ability to import macros from other crates, hurray! However, 
> I'd like to propose adjusting the current way of using them to be more like 
> importing/exporting other symbols of a crate.
> 
> 1) It's more consistent, makes it easier to find where macros came from.
> 2) Current usage brings name collisions.
> 
> 
> Current example:
> 
> pub mod foo {
>   // assume other macros as well
>   #[macro_export]
>   macro_rules! bar ( ... )
> }
> 
> pub mod baz {
>   // assume other macros as well
>   #[macro_export]
>   macro_rules! bar ( ... )
> }
> 
> mod herp {
>   // i want bar! from foo, and some other macros from baz
>   [phase(syntax)]
>   use super::foo;
>   [phase(syntax)]
>   use super::baz;
> 
>   pub Derp = bar!(); // which bar? is this an ICE? or logic error?
> }
> 
> Proposed example:
> 
> pub mod foo {
>   pub marco_rules! bar ( ... );
> }
> 
> pub mod baz {
>   pub marco_rules! bar ( ... );
>   pub marco_rules! quux ( ... );
> }
> 
> mod herp {
>   use super::foo::bar!;
>   use super::baz::quux!;
>   // using same name macros, no problem
>   use baz! = super::baz::bar!;
> 
>   pub Derp = bar!(baz!());
> }
> ___
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> Rust-dev@mozilla.org
> https://mail.mozilla.org/listinfo/rust-dev

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Re: [rust-dev] RFC: Importing/exporting macros

[Corey Richardson]

This is problematic because name resolutions happens far after macro
expansion. I think this could be doable with an extremely limited
"macro module system", but I think it's not-very-good to have the same
path syntax for two incredibly different systems.

On Tue, Feb 25, 2014 at 4:39 PM, Sean McArthur  wrote:
> Rust now has the ability to import macros from other crates, hurray!
> However, I'd like to propose adjusting the current way of using them to be
> more like importing/exporting other symbols of a crate.
>
> 1) It's more consistent, makes it easier to find where macros came from.
> 2) Current usage brings name collisions.
>
>
> Current example:
>
> pub mod foo {
>   // assume other macros as well
>   #[macro_export]
>   macro_rules! bar ( ... )
> }
>
> pub mod baz {
>   // assume other macros as well
>   #[macro_export]
>   macro_rules! bar ( ... )
> }
>
> mod herp {
>   // i want bar! from foo, and some other macros from baz
>   [phase(syntax)]
>   use super::foo;
>   [phase(syntax)]
>   use super::baz;
>
>   pub Derp = bar!(); // which bar? is this an ICE? or logic error?
> }
>
> Proposed example:
>
> pub mod foo {
>   pub marco_rules! bar ( ... );
> }
>
> pub mod baz {
>   pub marco_rules! bar ( ... );
>   pub marco_rules! quux ( ... );
> }
>
> mod herp {
>   use super::foo::bar!;
>   use super::baz::quux!;
>   // using same name macros, no problem
>   use baz! = super::baz::bar!;
>
>   pub Derp = bar!(baz!());
> }
>
> ___
> Rust-dev mailing list
> Rust-dev@mozilla.org
> https://mail.mozilla.org/listinfo/rust-dev
>
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[rust-dev] RFC: Importing/exporting macros

[Sean McArthur]

Rust now has the ability to import macros from other crates, hurray!
However, I'd like to propose adjusting the current way of using them to be
more like importing/exporting other symbols of a crate.

1) It's more consistent, makes it easier to find where macros came from.
2) Current usage brings name collisions.


Current example:

pub mod foo {
  // assume other macros as well
  #[macro_export]
  macro_rules! bar ( ... )
}

pub mod baz {
  // assume other macros as well
  #[macro_export]
  macro_rules! bar ( ... )
}

mod herp {
  // i want bar! from foo, and some other macros from baz
  [phase(syntax)]
  use super::foo;
  [phase(syntax)]
  use super::baz;

  pub Derp = bar!(); // which bar? is this an ICE? or logic error?
}

Proposed example:

pub mod foo {
  pub marco_rules! bar ( ... );
}

pub mod baz {
  pub marco_rules! bar ( ... );
  pub marco_rules! quux ( ... );
}

mod herp {
  use super::foo::bar!;
  use super::baz::quux!;
  // using same name macros, no problem
  use baz! = super::baz::bar!;

  pub Derp = bar!(baz!());
}
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