Crate proc_macro

A support library for macro authors when defining new macros.

This library, provided by the standard distribution, provides the types consumed in the interfaces of procedurally defined macro definitions such as function-like macros #[proc_macro], macro attributes #[proc_macro_attribute] and custom derive attributes#[proc_macro_derive].

See the book for more.

Modules

token_stream	Public implementation details for the TokenStream type, such as iterators.
tracked_env	Experimental Tracked access to environment variables.

Macros

quote

Experimental quote!(..) accepts arbitrary tokens and expands into a TokenStream describing the input. For example, quote!(a + b) will produce a expression, that, when evaluated, constructs the TokenStream [Ident("a"), Punct('+', Alone), Ident("b")].

Structs

Group	A delimited token stream.
Ident	An identifier (ident).
LexError	Error returned from TokenStream::from_str.
Literal	A literal string ("hello"), byte string (b"hello"), character ('a'), byte character (b'a'), an integer or floating point number with or without a suffix (1, 1u8, 2.3, 2.3f32). Boolean literals like true and false do not belong here, they are Idents.
Punct	An Punct is an single punctuation character like +, - or #.
Span	A region of source code, along with macro expansion information.
TokenStream	The main type provided by this crate, representing an abstract stream of tokens, or, more specifically, a sequence of token trees. The type provide interfaces for iterating over those token trees and, conversely, collecting a number of token trees into one stream.
Diagnostic	Experimental A structure representing a diagnostic message and associated children messages.
LineColumn	Experimental A line-column pair representing the start or end of a Span.
SourceFile	Experimental The source file of a given Span.

Enums

Delimiter	Describes how a sequence of token trees is delimited.
Spacing	Whether an Punct is followed immediately by another Punct or followed by another token or whitespace.
TokenTree	A single token or a delimited sequence of token trees (e.g., [1, (), ..]).
Level	Experimental An enum representing a diagnostic level.

Traits

MultiSpan

Experimental Trait implemented by types that can be converted into a set of Spans.

Functions

is_available	Experimental Determines whether proc_macro has been made accessible to the currently running program.
quote	Experimental Quote a TokenStream into a TokenStream. This is the actual implementation of the quote!() proc macro.
quote_span	Experimental Quote a Span into a TokenStream. This is needed to implement a custom quoter.