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+//! [![github]](https://github.com/dtolnay/proc-macro2) [![crates-io]](https://crates.io/crates/proc-macro2) [![docs-rs]](crate)
+//!
+//! [github]: https://img.shields.io/badge/github-8da0cb?style=for-the-badge&labelColor=555555&logo=github
+//! [crates-io]: https://img.shields.io/badge/crates.io-fc8d62?style=for-the-badge&labelColor=555555&logo=rust
+//! [docs-rs]: https://img.shields.io/badge/docs.rs-66c2a5?style=for-the-badge&labelColor=555555&logo=docs.rs
+//!
+//! <br>
+//!
+//! A wrapper around the procedural macro API of the compiler's [`proc_macro`]
+//! crate. This library serves two purposes:
+//!
+//! [`proc_macro`]: https://doc.rust-lang.org/proc_macro/
+//!
+//! - **Bring proc-macro-like functionality to other contexts like build.rs and
+//! main.rs.** Types from `proc_macro` are entirely specific to procedural
+//! macros and cannot ever exist in code outside of a procedural macro.
+//! Meanwhile `proc_macro2` types may exist anywhere including non-macro code.
+//! By developing foundational libraries like [syn] and [quote] against
+//! `proc_macro2` rather than `proc_macro`, the procedural macro ecosystem
+//! becomes easily applicable to many other use cases and we avoid
+//! reimplementing non-macro equivalents of those libraries.
+//!
+//! - **Make procedural macros unit testable.** As a consequence of being
+//! specific to procedural macros, nothing that uses `proc_macro` can be
+//! executed from a unit test. In order for helper libraries or components of
+//! a macro to be testable in isolation, they must be implemented using
+//! `proc_macro2`.
+//!
+//! [syn]: https://github.com/dtolnay/syn
+//! [quote]: https://github.com/dtolnay/quote
+//!
+//! # Usage
+//!
+//! The skeleton of a typical procedural macro typically looks like this:
+//!
+//! ```
+//! extern crate proc_macro;
+//!
+//! # const IGNORE: &str = stringify! {
+//! #[proc_macro_derive(MyDerive)]
+//! # };
+//! # #[cfg(wrap_proc_macro)]
+//! pub fn my_derive(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
+//! let input = proc_macro2::TokenStream::from(input);
+//!
+//! let output: proc_macro2::TokenStream = {
+//! /* transform input */
+//! # input
+//! };
+//!
+//! proc_macro::TokenStream::from(output)
+//! }
+//! ```
+//!
+//! If parsing with [Syn], you'll use [`parse_macro_input!`] instead to
+//! propagate parse errors correctly back to the compiler when parsing fails.
+//!
+//! [`parse_macro_input!`]: https://docs.rs/syn/1.0/syn/macro.parse_macro_input.html
+//!
+//! # Unstable features
+//!
+//! The default feature set of proc-macro2 tracks the most recent stable
+//! compiler API. Functionality in `proc_macro` that is not yet stable is not
+//! exposed by proc-macro2 by default.
+//!
+//! To opt into the additional APIs available in the most recent nightly
+//! compiler, the `procmacro2_semver_exempt` config flag must be passed to
+//! rustc. We will polyfill those nightly-only APIs back to Rust 1.56.0. As
+//! these are unstable APIs that track the nightly compiler, minor versions of
+//! proc-macro2 may make breaking changes to them at any time.
+//!
+//! ```sh
+//! RUSTFLAGS='--cfg procmacro2_semver_exempt' cargo build
+//! ```
+//!
+//! Note that this must not only be done for your crate, but for any crate that
+//! depends on your crate. This infectious nature is intentional, as it serves
+//! as a reminder that you are outside of the normal semver guarantees.
+//!
+//! Semver exempt methods are marked as such in the proc-macro2 documentation.
+//!
+//! # Thread-Safety
+//!
+//! Most types in this crate are `!Sync` because the underlying compiler
+//! types make use of thread-local memory, meaning they cannot be accessed from
+//! a different thread.
+
+// Proc-macro2 types in rustdoc of other crates get linked to here.
+#![doc(html_root_url = "https://docs.rs/proc-macro2/1.0.66")]
+#![cfg_attr(any(proc_macro_span, super_unstable), feature(proc_macro_span))]
+#![cfg_attr(super_unstable, feature(proc_macro_def_site))]
+#![cfg_attr(doc_cfg, feature(doc_cfg))]
+#![allow(
+ clippy::cast_lossless,
+ clippy::cast_possible_truncation,
+ clippy::doc_markdown,
+ clippy::items_after_statements,
+ clippy::let_underscore_untyped,
+ clippy::manual_assert,
+ clippy::manual_range_contains,
+ clippy::must_use_candidate,
+ clippy::needless_doctest_main,
+ clippy::new_without_default,
+ clippy::return_self_not_must_use,
+ clippy::shadow_unrelated,
+ clippy::trivially_copy_pass_by_ref,
+ clippy::unnecessary_wraps,
+ clippy::unused_self,
+ clippy::used_underscore_binding,
+ clippy::vec_init_then_push
+)]
+
+#[cfg(all(procmacro2_semver_exempt, wrap_proc_macro, not(super_unstable)))]
+compile_error! {"\
+ Something is not right. If you've tried to turn on \
+ procmacro2_semver_exempt, you need to ensure that it \
+ is turned on for the compilation of the proc-macro2 \
+ build script as well.
+"}
+
+extern crate alloc;
+
+#[cfg(feature = "proc-macro")]
+extern crate proc_macro;
+
+mod marker;
+mod parse;
+mod rcvec;
+
+#[cfg(wrap_proc_macro)]
+mod detection;
+
+// Public for proc_macro2::fallback::force() and unforce(), but those are quite
+// a niche use case so we omit it from rustdoc.
+#[doc(hidden)]
+pub mod fallback;
+
+pub mod extra;
+
+#[cfg(not(wrap_proc_macro))]
+use crate::fallback as imp;
+#[path = "wrapper.rs"]
+#[cfg(wrap_proc_macro)]
+mod imp;
+
+#[cfg(span_locations)]
+mod location;
+
+use crate::extra::DelimSpan;
+use crate::marker::Marker;
+use core::cmp::Ordering;
+use core::fmt::{self, Debug, Display};
+use core::hash::{Hash, Hasher};
+use core::ops::RangeBounds;
+use core::str::FromStr;
+use std::error::Error;
+#[cfg(procmacro2_semver_exempt)]
+use std::path::PathBuf;
+
+#[cfg(span_locations)]
+pub use crate::location::LineColumn;
+
+/// An abstract stream of tokens, or more concretely a sequence of token trees.
+///
+/// This type provides interfaces for iterating over token trees and for
+/// collecting token trees into one stream.
+///
+/// Token stream is both the input and output of `#[proc_macro]`,
+/// `#[proc_macro_attribute]` and `#[proc_macro_derive]` definitions.
+#[derive(Clone)]
+pub struct TokenStream {
+ inner: imp::TokenStream,
+ _marker: Marker,
+}
+
+/// Error returned from `TokenStream::from_str`.
+pub struct LexError {
+ inner: imp::LexError,
+ _marker: Marker,
+}
+
+impl TokenStream {
+ fn _new(inner: imp::TokenStream) -> Self {
+ TokenStream {
+ inner,
+ _marker: Marker,
+ }
+ }
+
+ fn _new_fallback(inner: fallback::TokenStream) -> Self {
+ TokenStream {
+ inner: inner.into(),
+ _marker: Marker,
+ }
+ }
+
+ /// Returns an empty `TokenStream` containing no token trees.
+ pub fn new() -> Self {
+ TokenStream::_new(imp::TokenStream::new())
+ }
+
+ /// Checks if this `TokenStream` is empty.
+ pub fn is_empty(&self) -> bool {
+ self.inner.is_empty()
+ }
+}
+
+/// `TokenStream::default()` returns an empty stream,
+/// i.e. this is equivalent with `TokenStream::new()`.
+impl Default for TokenStream {
+ fn default() -> Self {
+ TokenStream::new()
+ }
+}
+
+/// Attempts to break the string into tokens and parse those tokens into a token
+/// stream.
+///
+/// May fail for a number of reasons, for example, if the string contains
+/// unbalanced delimiters or characters not existing in the language.
+///
+/// NOTE: Some errors may cause panics instead of returning `LexError`. We
+/// reserve the right to change these errors into `LexError`s later.
+impl FromStr for TokenStream {
+ type Err = LexError;
+
+ fn from_str(src: &str) -> Result<TokenStream, LexError> {
+ let e = src.parse().map_err(|e| LexError {
+ inner: e,
+ _marker: Marker,
+ })?;
+ Ok(TokenStream::_new(e))
+ }
+}
+
+#[cfg(feature = "proc-macro")]
+#[cfg_attr(doc_cfg, doc(cfg(feature = "proc-macro")))]
+impl From<proc_macro::TokenStream> for TokenStream {
+ fn from(inner: proc_macro::TokenStream) -> Self {
+ TokenStream::_new(inner.into())
+ }
+}
+
+#[cfg(feature = "proc-macro")]
+#[cfg_attr(doc_cfg, doc(cfg(feature = "proc-macro")))]
+impl From<TokenStream> for proc_macro::TokenStream {
+ fn from(inner: TokenStream) -> Self {
+ inner.inner.into()
+ }
+}
+
+impl From<TokenTree> for TokenStream {
+ fn from(token: TokenTree) -> Self {
+ TokenStream::_new(imp::TokenStream::from(token))
+ }
+}
+
+impl Extend<TokenTree> for TokenStream {
+ fn extend<I: IntoIterator<Item = TokenTree>>(&mut self, streams: I) {
+ self.inner.extend(streams);
+ }
+}
+
+impl Extend<TokenStream> for TokenStream {
+ fn extend<I: IntoIterator<Item = TokenStream>>(&mut self, streams: I) {
+ self.inner
+ .extend(streams.into_iter().map(|stream| stream.inner));
+ }
+}
+
+/// Collects a number of token trees into a single stream.
+impl FromIterator<TokenTree> for TokenStream {
+ fn from_iter<I: IntoIterator<Item = TokenTree>>(streams: I) -> Self {
+ TokenStream::_new(streams.into_iter().collect())
+ }
+}
+impl FromIterator<TokenStream> for TokenStream {
+ fn from_iter<I: IntoIterator<Item = TokenStream>>(streams: I) -> Self {
+ TokenStream::_new(streams.into_iter().map(|i| i.inner).collect())
+ }
+}
+
+/// Prints the token stream as a string that is supposed to be losslessly
+/// convertible back into the same token stream (modulo spans), except for
+/// possibly `TokenTree::Group`s with `Delimiter::None` delimiters and negative
+/// numeric literals.
+impl Display for TokenStream {
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ Display::fmt(&self.inner, f)
+ }
+}
+
+/// Prints token in a form convenient for debugging.
+impl Debug for TokenStream {
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ Debug::fmt(&self.inner, f)
+ }
+}
+
+impl LexError {
+ pub fn span(&self) -> Span {
+ Span::_new(self.inner.span())
+ }
+}
+
+impl Debug for LexError {
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ Debug::fmt(&self.inner, f)
+ }
+}
+
+impl Display for LexError {
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ Display::fmt(&self.inner, f)
+ }
+}
+
+impl Error for LexError {}
+
+/// The source file of a given `Span`.
+///
+/// This type is semver exempt and not exposed by default.
+#[cfg(all(procmacro2_semver_exempt, any(not(wrap_proc_macro), super_unstable)))]
+#[cfg_attr(doc_cfg, doc(cfg(procmacro2_semver_exempt)))]
+#[derive(Clone, PartialEq, Eq)]
+pub struct SourceFile {
+ inner: imp::SourceFile,
+ _marker: Marker,
+}
+
+#[cfg(all(procmacro2_semver_exempt, any(not(wrap_proc_macro), super_unstable)))]
+impl SourceFile {
+ fn _new(inner: imp::SourceFile) -> Self {
+ SourceFile {
+ inner,
+ _marker: Marker,
+ }
+ }
+
+ /// Get the path to this source file.
+ ///
+ /// ### Note
+ ///
+ /// If the code span associated with this `SourceFile` was generated by an
+ /// external macro, this may not be an actual path on the filesystem. Use
+ /// [`is_real`] to check.
+ ///
+ /// Also note that even if `is_real` returns `true`, if
+ /// `--remap-path-prefix` was passed on the command line, the path as given
+ /// may not actually be valid.
+ ///
+ /// [`is_real`]: #method.is_real
+ pub fn path(&self) -> PathBuf {
+ self.inner.path()
+ }
+
+ /// Returns `true` if this source file is a real source file, and not
+ /// generated by an external macro's expansion.
+ pub fn is_real(&self) -> bool {
+ self.inner.is_real()
+ }
+}
+
+#[cfg(all(procmacro2_semver_exempt, any(not(wrap_proc_macro), super_unstable)))]
+impl Debug for SourceFile {
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ Debug::fmt(&self.inner, f)
+ }
+}
+
+/// A region of source code, along with macro expansion information.
+#[derive(Copy, Clone)]
+pub struct Span {
+ inner: imp::Span,
+ _marker: Marker,
+}
+
+impl Span {
+ fn _new(inner: imp::Span) -> Self {
+ Span {
+ inner,
+ _marker: Marker,
+ }
+ }
+
+ fn _new_fallback(inner: fallback::Span) -> Self {
+ Span {
+ inner: inner.into(),
+ _marker: Marker,
+ }
+ }
+
+ /// The span of the invocation of the current procedural macro.
+ ///
+ /// Identifiers created with this span will be resolved as if they were
+ /// written directly at the macro call location (call-site hygiene) and
+ /// other code at the macro call site will be able to refer to them as well.
+ pub fn call_site() -> Self {
+ Span::_new(imp::Span::call_site())
+ }
+
+ /// The span located at the invocation of the procedural macro, but with
+ /// local variables, labels, and `$crate` resolved at the definition site
+ /// of the macro. This is the same hygiene behavior as `macro_rules`.
+ pub fn mixed_site() -> Self {
+ Span::_new(imp::Span::mixed_site())
+ }
+
+ /// A span that resolves at the macro definition site.
+ ///
+ /// This method is semver exempt and not exposed by default.
+ #[cfg(procmacro2_semver_exempt)]
+ #[cfg_attr(doc_cfg, doc(cfg(procmacro2_semver_exempt)))]
+ pub fn def_site() -> Self {
+ Span::_new(imp::Span::def_site())
+ }
+
+ /// Creates a new span with the same line/column information as `self` but
+ /// that resolves symbols as though it were at `other`.
+ pub fn resolved_at(&self, other: Span) -> Span {
+ Span::_new(self.inner.resolved_at(other.inner))
+ }
+
+ /// Creates a new span with the same name resolution behavior as `self` but
+ /// with the line/column information of `other`.
+ pub fn located_at(&self, other: Span) -> Span {
+ Span::_new(self.inner.located_at(other.inner))
+ }
+
+ /// Convert `proc_macro2::Span` to `proc_macro::Span`.
+ ///
+ /// This method is available when building with a nightly compiler, or when
+ /// building with rustc 1.29+ *without* semver exempt features.
+ ///
+ /// # Panics
+ ///
+ /// Panics if called from outside of a procedural macro. Unlike
+ /// `proc_macro2::Span`, the `proc_macro::Span` type can only exist within
+ /// the context of a procedural macro invocation.
+ #[cfg(wrap_proc_macro)]
+ pub fn unwrap(self) -> proc_macro::Span {
+ self.inner.unwrap()
+ }
+
+ // Soft deprecated. Please use Span::unwrap.
+ #[cfg(wrap_proc_macro)]
+ #[doc(hidden)]
+ pub fn unstable(self) -> proc_macro::Span {
+ self.unwrap()
+ }
+
+ /// The original source file into which this span points.
+ ///
+ /// This method is semver exempt and not exposed by default.
+ #[cfg(all(procmacro2_semver_exempt, any(not(wrap_proc_macro), super_unstable)))]
+ #[cfg_attr(doc_cfg, doc(cfg(procmacro2_semver_exempt)))]
+ pub fn source_file(&self) -> SourceFile {
+ SourceFile::_new(self.inner.source_file())
+ }
+
+ /// Get the starting line/column in the source file for this span.
+ ///
+ /// This method requires the `"span-locations"` feature to be enabled.
+ ///
+ /// When executing in a procedural macro context, the returned line/column
+ /// are only meaningful if compiled with a nightly toolchain. The stable
+ /// toolchain does not have this information available. When executing
+ /// outside of a procedural macro, such as main.rs or build.rs, the
+ /// line/column are always meaningful regardless of toolchain.
+ #[cfg(span_locations)]
+ #[cfg_attr(doc_cfg, doc(cfg(feature = "span-locations")))]
+ pub fn start(&self) -> LineColumn {
+ self.inner.start()
+ }
+
+ /// Get the ending line/column in the source file for this span.
+ ///
+ /// This method requires the `"span-locations"` feature to be enabled.
+ ///
+ /// When executing in a procedural macro context, the returned line/column
+ /// are only meaningful if compiled with a nightly toolchain. The stable
+ /// toolchain does not have this information available. When executing
+ /// outside of a procedural macro, such as main.rs or build.rs, the
+ /// line/column are always meaningful regardless of toolchain.
+ #[cfg(span_locations)]
+ #[cfg_attr(doc_cfg, doc(cfg(feature = "span-locations")))]
+ pub fn end(&self) -> LineColumn {
+ self.inner.end()
+ }
+
+ /// Create a new span encompassing `self` and `other`.
+ ///
+ /// Returns `None` if `self` and `other` are from different files.
+ ///
+ /// Warning: the underlying [`proc_macro::Span::join`] method is
+ /// nightly-only. When called from within a procedural macro not using a
+ /// nightly compiler, this method will always return `None`.
+ ///
+ /// [`proc_macro::Span::join`]: https://doc.rust-lang.org/proc_macro/struct.Span.html#method.join
+ pub fn join(&self, other: Span) -> Option<Span> {
+ self.inner.join(other.inner).map(Span::_new)
+ }
+
+ /// Compares two spans to see if they're equal.
+ ///
+ /// This method is semver exempt and not exposed by default.
+ #[cfg(procmacro2_semver_exempt)]
+ #[cfg_attr(doc_cfg, doc(cfg(procmacro2_semver_exempt)))]
+ pub fn eq(&self, other: &Span) -> bool {
+ self.inner.eq(&other.inner)
+ }
+
+ /// Returns the source text behind a span. This preserves the original
+ /// source code, including spaces and comments. It only returns a result if
+ /// the span corresponds to real source code.
+ ///
+ /// Note: The observable result of a macro should only rely on the tokens
+ /// and not on this source text. The result of this function is a best
+ /// effort to be used for diagnostics only.
+ pub fn source_text(&self) -> Option<String> {
+ self.inner.source_text()
+ }
+}
+
+/// Prints a span in a form convenient for debugging.
+impl Debug for Span {
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ Debug::fmt(&self.inner, f)
+ }
+}
+
+/// A single token or a delimited sequence of token trees (e.g. `[1, (), ..]`).
+#[derive(Clone)]
+pub enum TokenTree {
+ /// A token stream surrounded by bracket delimiters.
+ Group(Group),
+ /// An identifier.
+ Ident(Ident),
+ /// A single punctuation character (`+`, `,`, `$`, etc.).
+ Punct(Punct),
+ /// A literal character (`'a'`), string (`"hello"`), number (`2.3`), etc.
+ Literal(Literal),
+}
+
+impl TokenTree {
+ /// Returns the span of this tree, delegating to the `span` method of
+ /// the contained token or a delimited stream.
+ pub fn span(&self) -> Span {
+ match self {
+ TokenTree::Group(t) => t.span(),
+ TokenTree::Ident(t) => t.span(),
+ TokenTree::Punct(t) => t.span(),
+ TokenTree::Literal(t) => t.span(),
+ }
+ }
+
+ /// Configures the span for *only this token*.
+ ///
+ /// Note that if this token is a `Group` then this method will not configure
+ /// the span of each of the internal tokens, this will simply delegate to
+ /// the `set_span` method of each variant.
+ pub fn set_span(&mut self, span: Span) {
+ match self {
+ TokenTree::Group(t) => t.set_span(span),
+ TokenTree::Ident(t) => t.set_span(span),
+ TokenTree::Punct(t) => t.set_span(span),
+ TokenTree::Literal(t) => t.set_span(span),
+ }
+ }
+}
+
+impl From<Group> for TokenTree {
+ fn from(g: Group) -> Self {
+ TokenTree::Group(g)
+ }
+}
+
+impl From<Ident> for TokenTree {
+ fn from(g: Ident) -> Self {
+ TokenTree::Ident(g)
+ }
+}
+
+impl From<Punct> for TokenTree {
+ fn from(g: Punct) -> Self {
+ TokenTree::Punct(g)
+ }
+}
+
+impl From<Literal> for TokenTree {
+ fn from(g: Literal) -> Self {
+ TokenTree::Literal(g)
+ }
+}
+
+/// Prints the token tree as a string that is supposed to be losslessly
+/// convertible back into the same token tree (modulo spans), except for
+/// possibly `TokenTree::Group`s with `Delimiter::None` delimiters and negative
+/// numeric literals.
+impl Display for TokenTree {
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ match self {
+ TokenTree::Group(t) => Display::fmt(t, f),
+ TokenTree::Ident(t) => Display::fmt(t, f),
+ TokenTree::Punct(t) => Display::fmt(t, f),
+ TokenTree::Literal(t) => Display::fmt(t, f),
+ }
+ }
+}
+
+/// Prints token tree in a form convenient for debugging.
+impl Debug for TokenTree {
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ // Each of these has the name in the struct type in the derived debug,
+ // so don't bother with an extra layer of indirection
+ match self {
+ TokenTree::Group(t) => Debug::fmt(t, f),
+ TokenTree::Ident(t) => {
+ let mut debug = f.debug_struct("Ident");
+ debug.field("sym", &format_args!("{}", t));
+ imp::debug_span_field_if_nontrivial(&mut debug, t.span().inner);
+ debug.finish()
+ }
+ TokenTree::Punct(t) => Debug::fmt(t, f),
+ TokenTree::Literal(t) => Debug::fmt(t, f),
+ }
+ }
+}
+
+/// A delimited token stream.
+///
+/// A `Group` internally contains a `TokenStream` which is surrounded by
+/// `Delimiter`s.
+#[derive(Clone)]
+pub struct Group {
+ inner: imp::Group,
+}
+
+/// Describes how a sequence of token trees is delimited.
+#[derive(Copy, Clone, Debug, Eq, PartialEq)]
+pub enum Delimiter {
+ /// `( ... )`
+ Parenthesis,
+ /// `{ ... }`
+ Brace,
+ /// `[ ... ]`
+ Bracket,
+ /// `Ø ... Ø`
+ ///
+ /// An implicit delimiter, that may, for example, appear around tokens
+ /// coming from a "macro variable" `$var`. It is important to preserve
+ /// operator priorities in cases like `$var * 3` where `$var` is `1 + 2`.
+ /// Implicit delimiters may not survive roundtrip of a token stream through
+ /// a string.
+ None,
+}
+
+impl Group {
+ fn _new(inner: imp::Group) -> Self {
+ Group { inner }
+ }
+
+ fn _new_fallback(inner: fallback::Group) -> Self {
+ Group {
+ inner: inner.into(),
+ }
+ }
+
+ /// Creates a new `Group` with the given delimiter and token stream.
+ ///
+ /// This constructor will set the span for this group to
+ /// `Span::call_site()`. To change the span you can use the `set_span`
+ /// method below.
+ pub fn new(delimiter: Delimiter, stream: TokenStream) -> Self {
+ Group {
+ inner: imp::Group::new(delimiter, stream.inner),
+ }
+ }
+
+ /// Returns the punctuation used as the delimiter for this group: a set of
+ /// parentheses, square brackets, or curly braces.
+ pub fn delimiter(&self) -> Delimiter {
+ self.inner.delimiter()
+ }
+
+ /// Returns the `TokenStream` of tokens that are delimited in this `Group`.
+ ///
+ /// Note that the returned token stream does not include the delimiter
+ /// returned above.
+ pub fn stream(&self) -> TokenStream {
+ TokenStream::_new(self.inner.stream())
+ }
+
+ /// Returns the span for the delimiters of this token stream, spanning the
+ /// entire `Group`.
+ ///
+ /// ```text
+ /// pub fn span(&self) -> Span {
+ /// ^^^^^^^
+ /// ```
+ pub fn span(&self) -> Span {
+ Span::_new(self.inner.span())
+ }
+
+ /// Returns the span pointing to the opening delimiter of this group.
+ ///
+ /// ```text
+ /// pub fn span_open(&self) -> Span {
+ /// ^
+ /// ```
+ pub fn span_open(&self) -> Span {
+ Span::_new(self.inner.span_open())
+ }
+
+ /// Returns the span pointing to the closing delimiter of this group.
+ ///
+ /// ```text
+ /// pub fn span_close(&self) -> Span {
+ /// ^
+ /// ```
+ pub fn span_close(&self) -> Span {
+ Span::_new(self.inner.span_close())
+ }
+
+ /// Returns an object that holds this group's `span_open()` and
+ /// `span_close()` together (in a more compact representation than holding
+ /// those 2 spans individually).
+ pub fn delim_span(&self) -> DelimSpan {
+ DelimSpan::new(&self.inner)
+ }
+
+ /// Configures the span for this `Group`'s delimiters, but not its internal
+ /// tokens.
+ ///
+ /// This method will **not** set the span of all the internal tokens spanned
+ /// by this group, but rather it will only set the span of the delimiter
+ /// tokens at the level of the `Group`.
+ pub fn set_span(&mut self, span: Span) {
+ self.inner.set_span(span.inner);
+ }
+}
+
+/// Prints the group as a string that should be losslessly convertible back
+/// into the same group (modulo spans), except for possibly `TokenTree::Group`s
+/// with `Delimiter::None` delimiters.
+impl Display for Group {
+ fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+ Display::fmt(&self.inner, formatter)
+ }
+}
+
+impl Debug for Group {
+ fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+ Debug::fmt(&self.inner, formatter)
+ }
+}
+
+/// A `Punct` is a single punctuation character like `+`, `-` or `#`.
+///
+/// Multicharacter operators like `+=` are represented as two instances of
+/// `Punct` with different forms of `Spacing` returned.
+#[derive(Clone)]
+pub struct Punct {
+ ch: char,
+ spacing: Spacing,
+ span: Span,
+}
+
+/// Whether a `Punct` is followed immediately by another `Punct` or followed by
+/// another token or whitespace.
+#[derive(Copy, Clone, Debug, Eq, PartialEq)]
+pub enum Spacing {
+ /// E.g. `+` is `Alone` in `+ =`, `+ident` or `+()`.
+ Alone,
+ /// E.g. `+` is `Joint` in `+=` or `'` is `Joint` in `'#`.
+ ///
+ /// Additionally, single quote `'` can join with identifiers to form
+ /// lifetimes `'ident`.
+ Joint,
+}
+
+impl Punct {
+ /// Creates a new `Punct` from the given character and spacing.
+ ///
+ /// The `ch` argument must be a valid punctuation character permitted by the
+ /// language, otherwise the function will panic.
+ ///
+ /// The returned `Punct` will have the default span of `Span::call_site()`
+ /// which can be further configured with the `set_span` method below.
+ pub fn new(ch: char, spacing: Spacing) -> Self {
+ Punct {
+ ch,
+ spacing,
+ span: Span::call_site(),
+ }
+ }
+
+ /// Returns the value of this punctuation character as `char`.
+ pub fn as_char(&self) -> char {
+ self.ch
+ }
+
+ /// Returns the spacing of this punctuation character, indicating whether
+ /// it's immediately followed by another `Punct` in the token stream, so
+ /// they can potentially be combined into a multicharacter operator
+ /// (`Joint`), or it's followed by some other token or whitespace (`Alone`)
+ /// so the operator has certainly ended.
+ pub fn spacing(&self) -> Spacing {
+ self.spacing
+ }
+
+ /// Returns the span for this punctuation character.
+ pub fn span(&self) -> Span {
+ self.span
+ }
+
+ /// Configure the span for this punctuation character.
+ pub fn set_span(&mut self, span: Span) {
+ self.span = span;
+ }
+}
+
+/// Prints the punctuation character as a string that should be losslessly
+/// convertible back into the same character.
+impl Display for Punct {
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ Display::fmt(&self.ch, f)
+ }
+}
+
+impl Debug for Punct {
+ fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+ let mut debug = fmt.debug_struct("Punct");
+ debug.field("char", &self.ch);
+ debug.field("spacing", &self.spacing);
+ imp::debug_span_field_if_nontrivial(&mut debug, self.span.inner);
+ debug.finish()
+ }
+}
+
+/// A word of Rust code, which may be a keyword or legal variable name.
+///
+/// An identifier consists of at least one Unicode code point, the first of
+/// which has the XID_Start property and the rest of which have the XID_Continue
+/// property.
+///
+/// - The empty string is not an identifier. Use `Option<Ident>`.
+/// - A lifetime is not an identifier. Use `syn::Lifetime` instead.
+///
+/// An identifier constructed with `Ident::new` is permitted to be a Rust
+/// keyword, though parsing one through its [`Parse`] implementation rejects
+/// Rust keywords. Use `input.call(Ident::parse_any)` when parsing to match the
+/// behaviour of `Ident::new`.
+///
+/// [`Parse`]: https://docs.rs/syn/1.0/syn/parse/trait.Parse.html
+///
+/// # Examples
+///
+/// A new ident can be created from a string using the `Ident::new` function.
+/// A span must be provided explicitly which governs the name resolution
+/// behavior of the resulting identifier.
+///
+/// ```
+/// use proc_macro2::{Ident, Span};
+///
+/// fn main() {
+/// let call_ident = Ident::new("calligraphy", Span::call_site());
+///
+/// println!("{}", call_ident);
+/// }
+/// ```
+///
+/// An ident can be interpolated into a token stream using the `quote!` macro.
+///
+/// ```
+/// use proc_macro2::{Ident, Span};
+/// use quote::quote;
+///
+/// fn main() {
+/// let ident = Ident::new("demo", Span::call_site());
+///
+/// // Create a variable binding whose name is this ident.
+/// let expanded = quote! { let #ident = 10; };
+///
+/// // Create a variable binding with a slightly different name.
+/// let temp_ident = Ident::new(&format!("new_{}", ident), Span::call_site());
+/// let expanded = quote! { let #temp_ident = 10; };
+/// }
+/// ```
+///
+/// A string representation of the ident is available through the `to_string()`
+/// method.
+///
+/// ```
+/// # use proc_macro2::{Ident, Span};
+/// #
+/// # let ident = Ident::new("another_identifier", Span::call_site());
+/// #
+/// // Examine the ident as a string.
+/// let ident_string = ident.to_string();
+/// if ident_string.len() > 60 {
+/// println!("Very long identifier: {}", ident_string)
+/// }
+/// ```
+#[derive(Clone)]
+pub struct Ident {
+ inner: imp::Ident,
+ _marker: Marker,
+}
+
+impl Ident {
+ fn _new(inner: imp::Ident) -> Self {
+ Ident {
+ inner,
+ _marker: Marker,
+ }
+ }
+
+ /// Creates a new `Ident` with the given `string` as well as the specified
+ /// `span`.
+ ///
+ /// The `string` argument must be a valid identifier permitted by the
+ /// language, otherwise the function will panic.
+ ///
+ /// Note that `span`, currently in rustc, configures the hygiene information
+ /// for this identifier.
+ ///
+ /// As of this time `Span::call_site()` explicitly opts-in to "call-site"
+ /// hygiene meaning that identifiers created with this span will be resolved
+ /// as if they were written directly at the location of the macro call, and
+ /// other code at the macro call site will be able to refer to them as well.
+ ///
+ /// Later spans like `Span::def_site()` will allow to opt-in to
+ /// "definition-site" hygiene meaning that identifiers created with this
+ /// span will be resolved at the location of the macro definition and other
+ /// code at the macro call site will not be able to refer to them.
+ ///
+ /// Due to the current importance of hygiene this constructor, unlike other
+ /// tokens, requires a `Span` to be specified at construction.
+ ///
+ /// # Panics
+ ///
+ /// Panics if the input string is neither a keyword nor a legal variable
+ /// name. If you are not sure whether the string contains an identifier and
+ /// need to handle an error case, use
+ /// <a href="https://docs.rs/syn/1.0/syn/fn.parse_str.html"><code
+ /// style="padding-right:0;">syn::parse_str</code></a><code
+ /// style="padding-left:0;">::&lt;Ident&gt;</code>
+ /// rather than `Ident::new`.
+ pub fn new(string: &str, span: Span) -> Self {
+ Ident::_new(imp::Ident::new(string, span.inner))
+ }
+
+ /// Same as `Ident::new`, but creates a raw identifier (`r#ident`). The
+ /// `string` argument must be a valid identifier permitted by the language
+ /// (including keywords, e.g. `fn`). Keywords which are usable in path
+ /// segments (e.g. `self`, `super`) are not supported, and will cause a
+ /// panic.
+ pub fn new_raw(string: &str, span: Span) -> Self {
+ Ident::_new_raw(string, span)
+ }
+
+ fn _new_raw(string: &str, span: Span) -> Self {
+ Ident::_new(imp::Ident::new_raw(string, span.inner))
+ }
+
+ /// Returns the span of this `Ident`.
+ pub fn span(&self) -> Span {
+ Span::_new(self.inner.span())
+ }
+
+ /// Configures the span of this `Ident`, possibly changing its hygiene
+ /// context.
+ pub fn set_span(&mut self, span: Span) {
+ self.inner.set_span(span.inner);
+ }
+}
+
+impl PartialEq for Ident {
+ fn eq(&self, other: &Ident) -> bool {
+ self.inner == other.inner
+ }
+}
+
+impl<T> PartialEq<T> for Ident
+where
+ T: ?Sized + AsRef<str>,
+{
+ fn eq(&self, other: &T) -> bool {
+ self.inner == other
+ }
+}
+
+impl Eq for Ident {}
+
+impl PartialOrd for Ident {
+ fn partial_cmp(&self, other: &Ident) -> Option<Ordering> {
+ Some(self.cmp(other))
+ }
+}
+
+impl Ord for Ident {
+ fn cmp(&self, other: &Ident) -> Ordering {
+ self.to_string().cmp(&other.to_string())
+ }
+}
+
+impl Hash for Ident {
+ fn hash<H: Hasher>(&self, hasher: &mut H) {
+ self.to_string().hash(hasher);
+ }
+}
+
+/// Prints the identifier as a string that should be losslessly convertible back
+/// into the same identifier.
+impl Display for Ident {
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ Display::fmt(&self.inner, f)
+ }
+}
+
+impl Debug for Ident {
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ Debug::fmt(&self.inner, f)
+ }
+}
+
+/// 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
+/// `Ident`s.
+#[derive(Clone)]
+pub struct Literal {
+ inner: imp::Literal,
+ _marker: Marker,
+}
+
+macro_rules! suffixed_int_literals {
+ ($($name:ident => $kind:ident,)*) => ($(
+ /// Creates a new suffixed integer literal with the specified value.
+ ///
+ /// This function will create an integer like `1u32` where the integer
+ /// value specified is the first part of the token and the integral is
+ /// also suffixed at the end. Literals created from negative numbers may
+ /// not survive roundtrips through `TokenStream` or strings and may be
+ /// broken into two tokens (`-` and positive literal).
+ ///
+ /// Literals created through this method have the `Span::call_site()`
+ /// span by default, which can be configured with the `set_span` method
+ /// below.
+ pub fn $name(n: $kind) -> Literal {
+ Literal::_new(imp::Literal::$name(n))
+ }
+ )*)
+}
+
+macro_rules! unsuffixed_int_literals {
+ ($($name:ident => $kind:ident,)*) => ($(
+ /// Creates a new unsuffixed integer literal with the specified value.
+ ///
+ /// This function will create an integer like `1` where the integer
+ /// value specified is the first part of the token. No suffix is
+ /// specified on this token, meaning that invocations like
+ /// `Literal::i8_unsuffixed(1)` are equivalent to
+ /// `Literal::u32_unsuffixed(1)`. Literals created from negative numbers
+ /// may not survive roundtrips through `TokenStream` or strings and may
+ /// be broken into two tokens (`-` and positive literal).
+ ///
+ /// Literals created through this method have the `Span::call_site()`
+ /// span by default, which can be configured with the `set_span` method
+ /// below.
+ pub fn $name(n: $kind) -> Literal {
+ Literal::_new(imp::Literal::$name(n))
+ }
+ )*)
+}
+
+impl Literal {
+ fn _new(inner: imp::Literal) -> Self {
+ Literal {
+ inner,
+ _marker: Marker,
+ }
+ }
+
+ fn _new_fallback(inner: fallback::Literal) -> Self {
+ Literal {
+ inner: inner.into(),
+ _marker: Marker,
+ }
+ }
+
+ suffixed_int_literals! {
+ u8_suffixed => u8,
+ u16_suffixed => u16,
+ u32_suffixed => u32,
+ u64_suffixed => u64,
+ u128_suffixed => u128,
+ usize_suffixed => usize,
+ i8_suffixed => i8,
+ i16_suffixed => i16,
+ i32_suffixed => i32,
+ i64_suffixed => i64,
+ i128_suffixed => i128,
+ isize_suffixed => isize,
+ }
+
+ unsuffixed_int_literals! {
+ u8_unsuffixed => u8,
+ u16_unsuffixed => u16,
+ u32_unsuffixed => u32,
+ u64_unsuffixed => u64,
+ u128_unsuffixed => u128,
+ usize_unsuffixed => usize,
+ i8_unsuffixed => i8,
+ i16_unsuffixed => i16,
+ i32_unsuffixed => i32,
+ i64_unsuffixed => i64,
+ i128_unsuffixed => i128,
+ isize_unsuffixed => isize,
+ }
+
+ /// Creates a new unsuffixed floating-point literal.
+ ///
+ /// This constructor is similar to those like `Literal::i8_unsuffixed` where
+ /// the float's value is emitted directly into the token but no suffix is
+ /// used, so it may be inferred to be a `f64` later in the compiler.
+ /// Literals created from negative numbers may not survive round-trips
+ /// through `TokenStream` or strings and may be broken into two tokens (`-`
+ /// and positive literal).
+ ///
+ /// # Panics
+ ///
+ /// This function requires that the specified float is finite, for example
+ /// if it is infinity or NaN this function will panic.
+ pub fn f64_unsuffixed(f: f64) -> Literal {
+ assert!(f.is_finite());
+ Literal::_new(imp::Literal::f64_unsuffixed(f))
+ }
+
+ /// Creates a new suffixed floating-point literal.
+ ///
+ /// This constructor will create a literal like `1.0f64` where the value
+ /// specified is the preceding part of the token and `f64` is the suffix of
+ /// the token. This token will always be inferred to be an `f64` in the
+ /// compiler. Literals created from negative numbers may not survive
+ /// round-trips through `TokenStream` or strings and may be broken into two
+ /// tokens (`-` and positive literal).
+ ///
+ /// # Panics
+ ///
+ /// This function requires that the specified float is finite, for example
+ /// if it is infinity or NaN this function will panic.
+ pub fn f64_suffixed(f: f64) -> Literal {
+ assert!(f.is_finite());
+ Literal::_new(imp::Literal::f64_suffixed(f))
+ }
+
+ /// Creates a new unsuffixed floating-point literal.
+ ///
+ /// This constructor is similar to those like `Literal::i8_unsuffixed` where
+ /// the float's value is emitted directly into the token but no suffix is
+ /// used, so it may be inferred to be a `f64` later in the compiler.
+ /// Literals created from negative numbers may not survive round-trips
+ /// through `TokenStream` or strings and may be broken into two tokens (`-`
+ /// and positive literal).
+ ///
+ /// # Panics
+ ///
+ /// This function requires that the specified float is finite, for example
+ /// if it is infinity or NaN this function will panic.
+ pub fn f32_unsuffixed(f: f32) -> Literal {
+ assert!(f.is_finite());
+ Literal::_new(imp::Literal::f32_unsuffixed(f))
+ }
+
+ /// Creates a new suffixed floating-point literal.
+ ///
+ /// This constructor will create a literal like `1.0f32` where the value
+ /// specified is the preceding part of the token and `f32` is the suffix of
+ /// the token. This token will always be inferred to be an `f32` in the
+ /// compiler. Literals created from negative numbers may not survive
+ /// round-trips through `TokenStream` or strings and may be broken into two
+ /// tokens (`-` and positive literal).
+ ///
+ /// # Panics
+ ///
+ /// This function requires that the specified float is finite, for example
+ /// if it is infinity or NaN this function will panic.
+ pub fn f32_suffixed(f: f32) -> Literal {
+ assert!(f.is_finite());
+ Literal::_new(imp::Literal::f32_suffixed(f))
+ }
+
+ /// String literal.
+ pub fn string(string: &str) -> Literal {
+ Literal::_new(imp::Literal::string(string))
+ }
+
+ /// Character literal.
+ pub fn character(ch: char) -> Literal {
+ Literal::_new(imp::Literal::character(ch))
+ }
+
+ /// Byte string literal.
+ pub fn byte_string(s: &[u8]) -> Literal {
+ Literal::_new(imp::Literal::byte_string(s))
+ }
+
+ /// Returns the span encompassing this literal.
+ pub fn span(&self) -> Span {
+ Span::_new(self.inner.span())
+ }
+
+ /// Configures the span associated for this literal.
+ pub fn set_span(&mut self, span: Span) {
+ self.inner.set_span(span.inner);
+ }
+
+ /// Returns a `Span` that is a subset of `self.span()` containing only
+ /// the source bytes in range `range`. Returns `None` if the would-be
+ /// trimmed span is outside the bounds of `self`.
+ ///
+ /// Warning: the underlying [`proc_macro::Literal::subspan`] method is
+ /// nightly-only. When called from within a procedural macro not using a
+ /// nightly compiler, this method will always return `None`.
+ ///
+ /// [`proc_macro::Literal::subspan`]: https://doc.rust-lang.org/proc_macro/struct.Literal.html#method.subspan
+ pub fn subspan<R: RangeBounds<usize>>(&self, range: R) -> Option<Span> {
+ self.inner.subspan(range).map(Span::_new)
+ }
+
+ // Intended for the `quote!` macro to use when constructing a proc-macro2
+ // token out of a macro_rules $:literal token, which is already known to be
+ // a valid literal. This avoids reparsing/validating the literal's string
+ // representation. This is not public API other than for quote.
+ #[doc(hidden)]
+ pub unsafe fn from_str_unchecked(repr: &str) -> Self {
+ Literal::_new(imp::Literal::from_str_unchecked(repr))
+ }
+}
+
+impl FromStr for Literal {
+ type Err = LexError;
+
+ fn from_str(repr: &str) -> Result<Self, LexError> {
+ repr.parse().map(Literal::_new).map_err(|inner| LexError {
+ inner,
+ _marker: Marker,
+ })
+ }
+}
+
+impl Debug for Literal {
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ Debug::fmt(&self.inner, f)
+ }
+}
+
+impl Display for Literal {
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ Display::fmt(&self.inner, f)
+ }
+}
+
+/// Public implementation details for the `TokenStream` type, such as iterators.
+pub mod token_stream {
+ use crate::marker::Marker;
+ use crate::{imp, TokenTree};
+ use core::fmt::{self, Debug};
+
+ pub use crate::TokenStream;
+
+ /// An iterator over `TokenStream`'s `TokenTree`s.
+ ///
+ /// The iteration is "shallow", e.g. the iterator doesn't recurse into
+ /// delimited groups, and returns whole groups as token trees.
+ #[derive(Clone)]
+ pub struct IntoIter {
+ inner: imp::TokenTreeIter,
+ _marker: Marker,
+ }
+
+ impl Iterator for IntoIter {
+ type Item = TokenTree;
+
+ fn next(&mut self) -> Option<TokenTree> {
+ self.inner.next()
+ }
+
+ fn size_hint(&self) -> (usize, Option<usize>) {
+ self.inner.size_hint()
+ }
+ }
+
+ impl Debug for IntoIter {
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ f.write_str("TokenStream ")?;
+ f.debug_list().entries(self.clone()).finish()
+ }
+ }
+
+ impl IntoIterator for TokenStream {
+ type Item = TokenTree;
+ type IntoIter = IntoIter;
+
+ fn into_iter(self) -> IntoIter {
+ IntoIter {
+ inner: self.inner.into_iter(),
+ _marker: Marker,
+ }
+ }
+ }
+}