pub enum SyntaxExtensionKind {
    Bang(Box<dyn BangProcMacro + DynSync + DynSend>),
    LegacyBang(Box<dyn TTMacroExpander + DynSync + DynSend>),
    Attr(Box<dyn AttrProcMacro + DynSync + DynSend>),
    LegacyAttr(Box<dyn MultiItemModifier + DynSync + DynSend>),
    NonMacroAttr,
    Derive(Box<dyn MultiItemModifier + DynSync + DynSend>),
    LegacyDerive(Box<dyn MultiItemModifier + DynSync + DynSend>),
}
Expand description

A syntax extension kind.

Variants§

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Bang(Box<dyn BangProcMacro + DynSync + DynSend>)

Tuple Fields

§0: Box<dyn BangProcMacro + DynSync + DynSend>

An expander with signature TokenStream -> TokenStream.

A token-based function-like macro.

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LegacyBang(Box<dyn TTMacroExpander + DynSync + DynSend>)

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§0: Box<dyn TTMacroExpander + DynSync + DynSend>

An expander with signature TokenStream -> AST.

An AST-based function-like macro.

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Attr(Box<dyn AttrProcMacro + DynSync + DynSend>)

Tuple Fields

§0: Box<dyn AttrProcMacro + DynSync + DynSend>

An expander with signature (TokenStream, TokenStream) -> TokenStream. The first TokenSteam is the attribute itself, the second is the annotated item. The produced TokenSteam replaces the input TokenSteam.

A token-based attribute macro.

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LegacyAttr(Box<dyn MultiItemModifier + DynSync + DynSend>)

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§0: Box<dyn MultiItemModifier + DynSync + DynSend>

An expander with signature (AST, AST) -> AST. The first AST fragment is the attribute itself, the second is the annotated item. The produced AST fragment replaces the input AST fragment.

An AST-based attribute macro.

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NonMacroAttr

A trivial attribute “macro” that does nothing, only keeps the attribute and marks it as inert, thus making it ineligible for further expansion.

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Derive(Box<dyn MultiItemModifier + DynSync + DynSend>)

Tuple Fields

§0: Box<dyn MultiItemModifier + DynSync + DynSend>

An expander with signature TokenStream -> TokenStream. The produced TokenSteam is appended to the input TokenSteam.

FIXME: The text above describes how this should work. Currently it is handled identically to LegacyDerive. It should be migrated to a token-based representation like Bang and Attr, instead of using MultiItemModifier.

A token-based derive macro.

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LegacyDerive(Box<dyn MultiItemModifier + DynSync + DynSend>)

Tuple Fields

§0: Box<dyn MultiItemModifier + DynSync + DynSend>

An expander with signature AST -> AST. The produced AST fragment is appended to the input AST fragment.

An AST-based derive macro.

Auto Trait Implementations§

Blanket Implementations§

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impl<T> Any for Twhere T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for Twhere T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for Twhere T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for Twhere U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T, U> TryFrom<U> for Twhere U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for Twhere U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.

Layout§

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 24 bytes

Size for each variant:

  • Bang: 16 bytes
  • LegacyBang: 16 bytes
  • Attr: 16 bytes
  • LegacyAttr: 16 bytes
  • NonMacroAttr: 0 bytes
  • Derive: 16 bytes
  • LegacyDerive: 16 bytes