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Use local_inner_macros to resolve all helper macros within $crate #165

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merged 1 commit into from
Jul 27, 2018
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Use local_inner_macros to resolve all helper macros within $crate #165

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22 changes: 16 additions & 6 deletions src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -325,7 +325,7 @@ pub extern crate core as _core;
/// assert_eq!(format!("{:?}", Flags::B), "B");
/// }
/// ```
#[macro_export]
#[macro_export(local_inner_macros)]
macro_rules! bitflags {
(
$(#[$outer:meta])*
Expand Down Expand Up @@ -386,7 +386,7 @@ macro_rules! bitflags {
};
}

#[macro_export]
#[macro_export(local_inner_macros)]
#[doc(hidden)]
macro_rules! __bitflags {
(
Expand Down Expand Up @@ -415,7 +415,7 @@ macro_rules! __bitflags {
};
}

#[macro_export]
#[macro_export(local_inner_macros)]
#[doc(hidden)]
macro_rules! __impl_bitflags {
(
Expand Down Expand Up @@ -467,14 +467,14 @@ macro_rules! __impl_bitflags {
$(
if <$BitFlags as __BitFlags>::$Flag(self) {
if !first {
try!(f.write_str(" | "));
f.write_str(" | ")?;
}
first = false;
try!(f.write_str(stringify!($Flag)));
f.write_str(__bitflags_stringify!($Flag))?;
}
)+
if first {
try!(f.write_str("(empty)"));
f.write_str("(empty)")?;
}
Ok(())
}
Expand Down Expand Up @@ -771,6 +771,16 @@ macro_rules! __impl_bitflags {
};
}

// Same as std::stringify but callable from __impl_bitflags, which needs to use
// local_inner_macros so can only directly call macros from this crate.
#[macro_export]
#[doc(hidden)]
macro_rules! __bitflags_stringify {
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Ah interesting... Is this a workaround to an inherent feature of local_inner_macros or just an implementation detail that might not be necessary in the future?

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This is what local_inner_macros means -- macro calls in the expansion are resolved as local helper macros. So a local_inner_macros macro cannot directly call a macro from a different crate, such as stringify from std.

($s:ident) => {
stringify!($s)
};
}

#[cfg(feature = "example_generated")]
pub mod example_generated;

Expand Down