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.

Re-exports

pub use diagnostic::Diagnostic;Experimental

pub use diagnostic::Level;Experimental

pub use diagnostic::MultiSpan;Experimental

pub use to_tokens::ToTokens;Experimental

pub use quote::quote;Experimental

pub use quote::quote_span;Experimental

Modules

diagnostic 🔒

escape 🔒

to_tokens 🔒

token_stream

Public implementation details for the TokenStream type, such as iterators.

bridge 👻 Experimental

Internal interface for communicating between a proc_macro client (a proc macro crate) and a proc_macro server (a compiler front-end).

quote 🔒👻 Experimental

Quasiquoter

tracked_envExperimental

Tracked access to environment variables.

tracked_pathExperimental

Tracked access to additional files.

Macros

diagnostic_method 🔒

suffixed_int_literals 🔒

unsuffixed_int_literals 🔒

quoteExperimental

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

Structs

ConcatStreamsHelper 🔒

Non-generic helper for implementing FromIterator<TokenStream> and Extend<TokenStream> with less monomorphization in calling crates.

ConcatTreesHelper 🔒

Non-generic helper for implementing FromIterator<TokenTree> and Extend<TokenTree> with less monomorphization in calling crates.

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"), C string (c"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

A Punct is a single punctuation character such as +, - 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 provides interfaces for iterating over those token trees and, conversely, collecting a number of token trees into one stream.

ExpandErrorExperimental

Error returned from TokenStream::expand_expr.

Enums

Delimiter

Describes how a sequence of token trees is delimited.

Spacing

Indicates whether a Punct token can join with the following token to form a multi-character operator.

TokenTree

A single token or a delimited sequence of token trees (e.g., [1, (), ..]).

ConversionErrorKindExperimental

Errors returned when trying to retrieve a literal unescaped value.

EscapeError

Errors and warnings that can occur during string unescaping. They mostly relate to malformed escape sequences, but there are a few that are about other problems.

Functions

is_available

Determines whether proc_macro has been made accessible to the currently running program.

tree_to_bridge_tree 🔒