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Diffstat (limited to 'library/proc_macro/src/lib.rs')
| -rw-r--r-- | library/proc_macro/src/lib.rs | 1183 |
1 files changed, 1183 insertions, 0 deletions
diff --git a/library/proc_macro/src/lib.rs b/library/proc_macro/src/lib.rs new file mode 100644 index 00000000000..c050a3c591c --- /dev/null +++ b/library/proc_macro/src/lib.rs @@ -0,0 +1,1183 @@ +//! 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. +//! +//! [the book]: ../book/ch19-06-macros.html#procedural-macros-for-generating-code-from-attributes + +#![stable(feature = "proc_macro_lib", since = "1.15.0")] +#![deny(missing_docs)] +#![doc( + html_root_url = "https://doc.rust-lang.org/nightly/", + html_playground_url = "https://play.rust-lang.org/", + issue_tracker_base_url = "https://github.com/rust-lang/rust/issues/", + test(no_crate_inject, attr(deny(warnings))), + test(attr(allow(dead_code, deprecated, unused_variables, unused_mut))) +)] +#![feature(nll)] +#![feature(staged_api)] +#![feature(allow_internal_unstable)] +#![feature(decl_macro)] +#![feature(extern_types)] +#![feature(in_band_lifetimes)] +#![feature(inner_deref)] +#![feature(negative_impls)] +#![feature(optin_builtin_traits)] +#![feature(restricted_std)] +#![feature(rustc_attrs)] +#![feature(min_specialization)] +#![recursion_limit = "256"] + +#[unstable(feature = "proc_macro_internals", issue = "27812")] +#[doc(hidden)] +pub mod bridge; + +mod diagnostic; + +#[unstable(feature = "proc_macro_diagnostic", issue = "54140")] +pub use diagnostic::{Diagnostic, Level, MultiSpan}; + +use std::cmp::Ordering; +use std::ops::{Bound, RangeBounds}; +use std::path::PathBuf; +use std::str::FromStr; +use std::{error, fmt, iter, mem}; + +/// Determines whether proc_macro has been made accessible to the currently +/// running program. +/// +/// The proc_macro crate is only intended for use inside the implementation of +/// procedural macros. All the functions in this crate panic if invoked from +/// outside of a procedural macro, such as from a build script or unit test or +/// ordinary Rust binary. +/// +/// With consideration for Rust libraries that are designed to support both +/// macro and non-macro use cases, `proc_macro::is_available()` provides a +/// non-panicking way to detect whether the infrastructure required to use the +/// API of proc_macro is presently available. Returns true if invoked from +/// inside of a procedural macro, false if invoked from any other binary. +#[unstable(feature = "proc_macro_is_available", issue = "71436")] +pub fn is_available() -> bool { + bridge::Bridge::is_available() +} + +/// 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. +/// +/// This is both the input and output of `#[proc_macro]`, `#[proc_macro_attribute]` +/// and `#[proc_macro_derive]` definitions. +#[stable(feature = "proc_macro_lib", since = "1.15.0")] +#[derive(Clone)] +pub struct TokenStream(bridge::client::TokenStream); + +#[stable(feature = "proc_macro_lib", since = "1.15.0")] +impl !Send for TokenStream {} +#[stable(feature = "proc_macro_lib", since = "1.15.0")] +impl !Sync for TokenStream {} + +/// Error returned from `TokenStream::from_str`. +#[stable(feature = "proc_macro_lib", since = "1.15.0")] +#[derive(Debug)] +pub struct LexError { + _inner: (), +} + +#[stable(feature = "proc_macro_lexerror_impls", since = "1.44.0")] +impl fmt::Display for LexError { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.write_str("cannot parse string into token stream") + } +} + +#[stable(feature = "proc_macro_lexerror_impls", since = "1.44.0")] +impl error::Error for LexError {} + +#[stable(feature = "proc_macro_lib", since = "1.15.0")] +impl !Send for LexError {} +#[stable(feature = "proc_macro_lib", since = "1.15.0")] +impl !Sync for LexError {} + +impl TokenStream { + /// Returns an empty `TokenStream` containing no token trees. + #[stable(feature = "proc_macro_lib2", since = "1.29.0")] + pub fn new() -> TokenStream { + TokenStream(bridge::client::TokenStream::new()) + } + + /// Checks if this `TokenStream` is empty. + #[stable(feature = "proc_macro_lib2", since = "1.29.0")] + pub fn is_empty(&self) -> bool { + self.0.is_empty() + } +} + +/// 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. +/// All tokens in the parsed stream get `Span::call_site()` spans. +/// +/// NOTE: some errors may cause panics instead of returning `LexError`. We reserve the right to +/// change these errors into `LexError`s later. +#[stable(feature = "proc_macro_lib", since = "1.15.0")] +impl FromStr for TokenStream { + type Err = LexError; + + fn from_str(src: &str) -> Result<TokenStream, LexError> { + Ok(TokenStream(bridge::client::TokenStream::from_str(src))) + } +} + +// N.B., the bridge only provides `to_string`, implement `fmt::Display` +// based on it (the reverse of the usual relationship between the two). +#[stable(feature = "proc_macro_lib", since = "1.15.0")] +impl ToString for TokenStream { + fn to_string(&self) -> String { + self.0.to_string() + } +} + +/// 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. +#[stable(feature = "proc_macro_lib", since = "1.15.0")] +impl fmt::Display for TokenStream { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.write_str(&self.to_string()) + } +} + +/// Prints token in a form convenient for debugging. +#[stable(feature = "proc_macro_lib", since = "1.15.0")] +impl fmt::Debug for TokenStream { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.write_str("TokenStream ")?; + f.debug_list().entries(self.clone()).finish() + } +} + +#[stable(feature = "proc_macro_token_stream_default", since = "1.45.0")] +impl Default for TokenStream { + fn default() -> Self { + TokenStream::new() + } +} + +#[unstable(feature = "proc_macro_quote", issue = "54722")] +pub use quote::{quote, quote_span}; + +/// Creates a token stream containing a single token tree. +#[stable(feature = "proc_macro_lib2", since = "1.29.0")] +impl From<TokenTree> for TokenStream { + fn from(tree: TokenTree) -> TokenStream { + TokenStream(bridge::client::TokenStream::from_token_tree(match tree { + TokenTree::Group(tt) => bridge::TokenTree::Group(tt.0), + TokenTree::Punct(tt) => bridge::TokenTree::Punct(tt.0), + TokenTree::Ident(tt) => bridge::TokenTree::Ident(tt.0), + TokenTree::Literal(tt) => bridge::TokenTree::Literal(tt.0), + })) + } +} + +/// Collects a number of token trees into a single stream. +#[stable(feature = "proc_macro_lib2", since = "1.29.0")] +impl iter::FromIterator<TokenTree> for TokenStream { + fn from_iter<I: IntoIterator<Item = TokenTree>>(trees: I) -> Self { + trees.into_iter().map(TokenStream::from).collect() + } +} + +/// A "flattening" operation on token streams, collects token trees +/// from multiple token streams into a single stream. +#[stable(feature = "proc_macro_lib", since = "1.15.0")] +impl iter::FromIterator<TokenStream> for TokenStream { + fn from_iter<I: IntoIterator<Item = TokenStream>>(streams: I) -> Self { + let mut builder = bridge::client::TokenStreamBuilder::new(); + streams.into_iter().for_each(|stream| builder.push(stream.0)); + TokenStream(builder.build()) + } +} + +#[stable(feature = "token_stream_extend", since = "1.30.0")] +impl Extend<TokenTree> for TokenStream { + fn extend<I: IntoIterator<Item = TokenTree>>(&mut self, trees: I) { + self.extend(trees.into_iter().map(TokenStream::from)); + } +} + +#[stable(feature = "token_stream_extend", since = "1.30.0")] +impl Extend<TokenStream> for TokenStream { + fn extend<I: IntoIterator<Item = TokenStream>>(&mut self, streams: I) { + // FIXME(eddyb) Use an optimized implementation if/when possible. + *self = iter::once(mem::replace(self, Self::new())).chain(streams).collect(); + } +} + +/// Public implementation details for the `TokenStream` type, such as iterators. +#[stable(feature = "proc_macro_lib2", since = "1.29.0")] +pub mod token_stream { + use crate::{bridge, Group, Ident, Literal, Punct, TokenStream, TokenTree}; + + /// 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)] + #[stable(feature = "proc_macro_lib2", since = "1.29.0")] + pub struct IntoIter(bridge::client::TokenStreamIter); + + #[stable(feature = "proc_macro_lib2", since = "1.29.0")] + impl Iterator for IntoIter { + type Item = TokenTree; + + fn next(&mut self) -> Option<TokenTree> { + self.0.next().map(|tree| match tree { + bridge::TokenTree::Group(tt) => TokenTree::Group(Group(tt)), + bridge::TokenTree::Punct(tt) => TokenTree::Punct(Punct(tt)), + bridge::TokenTree::Ident(tt) => TokenTree::Ident(Ident(tt)), + bridge::TokenTree::Literal(tt) => TokenTree::Literal(Literal(tt)), + }) + } + } + + #[stable(feature = "proc_macro_lib2", since = "1.29.0")] + impl IntoIterator for TokenStream { + type Item = TokenTree; + type IntoIter = IntoIter; + + fn into_iter(self) -> IntoIter { + IntoIter(self.0.into_iter()) + } + } +} + +/// `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")]`. +/// +/// Unquoting is done with `$`, and works by taking the single next ident as the unquoted term. +/// To quote `$` itself, use `$$`. +#[unstable(feature = "proc_macro_quote", issue = "54722")] +#[allow_internal_unstable(proc_macro_def_site)] +#[rustc_builtin_macro] +pub macro quote($($t:tt)*) { + /* compiler built-in */ +} + +#[unstable(feature = "proc_macro_internals", issue = "27812")] +#[doc(hidden)] +mod quote; + +/// A region of source code, along with macro expansion information. +#[stable(feature = "proc_macro_lib2", since = "1.29.0")] +#[derive(Copy, Clone)] +pub struct Span(bridge::client::Span); + +#[stable(feature = "proc_macro_lib2", since = "1.29.0")] +impl !Send for Span {} +#[stable(feature = "proc_macro_lib2", since = "1.29.0")] +impl !Sync for Span {} + +macro_rules! diagnostic_method { + ($name:ident, $level:expr) => { + /// Creates a new `Diagnostic` with the given `message` at the span + /// `self`. + #[unstable(feature = "proc_macro_diagnostic", issue = "54140")] + pub fn $name<T: Into<String>>(self, message: T) -> Diagnostic { + Diagnostic::spanned(self, $level, message) + } + }; +} + +impl Span { + /// A span that resolves at the macro definition site. + #[unstable(feature = "proc_macro_def_site", issue = "54724")] + pub fn def_site() -> Span { + Span(bridge::client::Span::def_site()) + } + + /// The span of the invocation of the current procedural macro. + /// Identifiers created with this span will be resolved as if they were written + /// directly at the macro call location (call-site hygiene) and other code + /// at the macro call site will be able to refer to them as well. + #[stable(feature = "proc_macro_lib2", since = "1.29.0")] + pub fn call_site() -> Span { + Span(bridge::client::Span::call_site()) + } + + /// A span that represents `macro_rules` hygiene, and sometimes resolves at the macro + /// definition site (local variables, labels, `$crate`) and sometimes at the macro + /// call site (everything else). + /// The span location is taken from the call-site. + #[stable(feature = "proc_macro_mixed_site", since = "1.45.0")] + pub fn mixed_site() -> Span { + Span(bridge::client::Span::mixed_site()) + } + + /// The original source file into which this span points. + #[unstable(feature = "proc_macro_span", issue = "54725")] + pub fn source_file(&self) -> SourceFile { + SourceFile(self.0.source_file()) + } + + /// The `Span` for the tokens in the previous macro expansion from which + /// `self` was generated from, if any. + #[unstable(feature = "proc_macro_span", issue = "54725")] + pub fn parent(&self) -> Option<Span> { + self.0.parent().map(Span) + } + + /// The span for the origin source code that `self` was generated from. If + /// this `Span` wasn't generated from other macro expansions then the return + /// value is the same as `*self`. + #[unstable(feature = "proc_macro_span", issue = "54725")] + pub fn source(&self) -> Span { + Span(self.0.source()) + } + + /// Gets the starting line/column in the source file for this span. + #[unstable(feature = "proc_macro_span", issue = "54725")] + pub fn start(&self) -> LineColumn { + self.0.start() + } + + /// Gets the ending line/column in the source file for this span. + #[unstable(feature = "proc_macro_span", issue = "54725")] + pub fn end(&self) -> LineColumn { + self.0.end() + } + + /// Creates a new span encompassing `self` and `other`. + /// + /// Returns `None` if `self` and `other` are from different files. + #[unstable(feature = "proc_macro_span", issue = "54725")] + pub fn join(&self, other: Span) -> Option<Span> { + self.0.join(other.0).map(Span) + } + + /// Creates a new span with the same line/column information as `self` but + /// that resolves symbols as though it were at `other`. + #[stable(feature = "proc_macro_span_resolved_at", since = "1.45.0")] + pub fn resolved_at(&self, other: Span) -> Span { + Span(self.0.resolved_at(other.0)) + } + + /// Creates a new span with the same name resolution behavior as `self` but + /// with the line/column information of `other`. + #[stable(feature = "proc_macro_span_located_at", since = "1.45.0")] + pub fn located_at(&self, other: Span) -> Span { + other.resolved_at(*self) + } + + /// Compares to spans to see if they're equal. + #[unstable(feature = "proc_macro_span", issue = "54725")] + pub fn eq(&self, other: &Span) -> bool { + self.0 == other.0 + } + + /// 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. + #[unstable(feature = "proc_macro_span", issue = "54725")] + pub fn source_text(&self) -> Option<String> { + self.0.source_text() + } + + diagnostic_method!(error, Level::Error); + diagnostic_method!(warning, Level::Warning); + diagnostic_method!(note, Level::Note); + diagnostic_method!(help, Level::Help); +} + +/// Prints a span in a form convenient for debugging. +#[stable(feature = "proc_macro_lib2", since = "1.29.0")] +impl fmt::Debug for Span { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + self.0.fmt(f) + } +} + +/// A line-column pair representing the start or end of a `Span`. +#[unstable(feature = "proc_macro_span", issue = "54725")] +#[derive(Copy, Clone, Debug, PartialEq, Eq)] +pub struct LineColumn { + /// The 1-indexed line in the source file on which the span starts or ends (inclusive). + #[unstable(feature = "proc_macro_span", issue = "54725")] + pub line: usize, + /// The 0-indexed column (in UTF-8 characters) in the source file on which + /// the span starts or ends (inclusive). + #[unstable(feature = "proc_macro_span", issue = "54725")] + pub column: usize, +} + +#[unstable(feature = "proc_macro_span", issue = "54725")] +impl !Send for LineColumn {} +#[unstable(feature = "proc_macro_span", issue = "54725")] +impl !Sync for LineColumn {} + +#[unstable(feature = "proc_macro_span", issue = "54725")] +impl Ord for LineColumn { + fn cmp(&self, other: &Self) -> Ordering { + self.line.cmp(&other.line).then(self.column.cmp(&other.column)) + } +} + +#[unstable(feature = "proc_macro_span", issue = "54725")] +impl PartialOrd for LineColumn { + fn partial_cmp(&self, other: &Self) -> Option<Ordering> { + Some(self.cmp(other)) + } +} + +/// The source file of a given `Span`. +#[unstable(feature = "proc_macro_span", issue = "54725")] +#[derive(Clone)] +pub struct SourceFile(bridge::client::SourceFile); + +impl SourceFile { + /// Gets the path to this source file. + /// + /// ### Note + /// If the code span associated with this `SourceFile` was generated by an external macro, this + /// 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 + #[unstable(feature = "proc_macro_span", issue = "54725")] + pub fn path(&self) -> PathBuf { + PathBuf::from(self.0.path()) + } + + /// Returns `true` if this source file is a real source file, and not generated by an external + /// macro's expansion. + #[unstable(feature = "proc_macro_span", issue = "54725")] + pub fn is_real(&self) -> bool { + // This is a hack until intercrate spans are implemented and we can have real source files + // for spans generated in external macros. + // https://github.com/rust-lang/rust/pull/43604#issuecomment-333334368 + self.0.is_real() + } +} + +#[unstable(feature = "proc_macro_span", issue = "54725")] +impl fmt::Debug for SourceFile { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("SourceFile") + .field("path", &self.path()) + .field("is_real", &self.is_real()) + .finish() + } +} + +#[unstable(feature = "proc_macro_span", issue = "54725")] +impl PartialEq for SourceFile { + fn eq(&self, other: &Self) -> bool { + self.0.eq(&other.0) + } +} + +#[unstable(feature = "proc_macro_span", issue = "54725")] +impl Eq for SourceFile {} + +/// A single token or a delimited sequence of token trees (e.g., `[1, (), ..]`). +#[stable(feature = "proc_macro_lib2", since = "1.29.0")] +#[derive(Clone)] +pub enum TokenTree { + /// A token stream surrounded by bracket delimiters. + #[stable(feature = "proc_macro_lib2", since = "1.29.0")] + Group(#[stable(feature = "proc_macro_lib2", since = "1.29.0")] Group), + /// An identifier. + #[stable(feature = "proc_macro_lib2", since = "1.29.0")] + Ident(#[stable(feature = "proc_macro_lib2", since = "1.29.0")] Ident), + /// A single punctuation character (`+`, `,`, `$`, etc.). + #[stable(feature = "proc_macro_lib2", since = "1.29.0")] + Punct(#[stable(feature = "proc_macro_lib2", since = "1.29.0")] Punct), + /// A literal character (`'a'`), string (`"hello"`), number (`2.3`), etc. + #[stable(feature = "proc_macro_lib2", since = "1.29.0")] + Literal(#[stable(feature = "proc_macro_lib2", since = "1.29.0")] Literal), +} + +#[stable(feature = "proc_macro_lib2", since = "1.29.0")] +impl !Send for TokenTree {} +#[stable(feature = "proc_macro_lib2", since = "1.29.0")] +impl !Sync for TokenTree {} + +impl TokenTree { + /// Returns the span of this tree, delegating to the `span` method of + /// the contained token or a delimited stream. + #[stable(feature = "proc_macro_lib2", since = "1.29.0")] + pub fn span(&self) -> Span { + match *self { + TokenTree::Group(ref t) => t.span(), + TokenTree::Ident(ref t) => t.span(), + TokenTree::Punct(ref t) => t.span(), + TokenTree::Literal(ref 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. + #[stable(feature = "proc_macro_lib2", since = "1.29.0")] + pub fn set_span(&mut self, span: Span) { + match *self { + TokenTree::Group(ref mut t) => t.set_span(span), + TokenTree::Ident(ref mut t) => t.set_span(span), + TokenTree::Punct(ref mut t) => t.set_span(span), + TokenTree::Literal(ref mut t) => t.set_span(span), + } + } +} + +/// Prints token tree in a form convenient for debugging. +#[stable(feature = "proc_macro_lib2", since = "1.29.0")] +impl fmt::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(ref tt) => tt.fmt(f), + TokenTree::Ident(ref tt) => tt.fmt(f), + TokenTree::Punct(ref tt) => tt.fmt(f), + TokenTree::Literal(ref tt) => tt.fmt(f), + } + } +} + +#[stable(feature = "proc_macro_lib2", since = "1.29.0")] +impl From<Group> for TokenTree { + fn from(g: Group) -> TokenTree { + TokenTree::Group(g) + } +} + +#[stable(feature = "proc_macro_lib2", since = "1.29.0")] +impl From<Ident> for TokenTree { + fn from(g: Ident) -> TokenTree { + TokenTree::Ident(g) + } +} + +#[stable(feature = "proc_macro_lib2", since = "1.29.0")] +impl From<Punct> for TokenTree { + fn from(g: Punct) -> TokenTree { + TokenTree::Punct(g) + } +} + +#[stable(feature = "proc_macro_lib2", since = "1.29.0")] +impl From<Literal> for TokenTree { + fn from(g: Literal) -> TokenTree { + TokenTree::Literal(g) + } +} + +// N.B., the bridge only provides `to_string`, implement `fmt::Display` +// based on it (the reverse of the usual relationship between the two). +#[stable(feature = "proc_macro_lib", since = "1.15.0")] +impl ToString for TokenTree { + fn to_string(&self) -> String { + match *self { + TokenTree::Group(ref t) => t.to_string(), + TokenTree::Ident(ref t) => t.to_string(), + TokenTree::Punct(ref t) => t.to_string(), + TokenTree::Literal(ref t) => t.to_string(), + } + } +} + +/// 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. +#[stable(feature = "proc_macro_lib2", since = "1.29.0")] +impl fmt::Display for TokenTree { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.write_str(&self.to_string()) + } +} + +/// A delimited token stream. +/// +/// A `Group` internally contains a `TokenStream` which is surrounded by `Delimiter`s. +#[derive(Clone)] +#[stable(feature = "proc_macro_lib2", since = "1.29.0")] +pub struct Group(bridge::client::Group); + +#[stable(feature = "proc_macro_lib2", since = "1.29.0")] +impl !Send for Group {} +#[stable(feature = "proc_macro_lib2", since = "1.29.0")] +impl !Sync for Group {} + +/// Describes how a sequence of token trees is delimited. +#[derive(Copy, Clone, Debug, PartialEq, Eq)] +#[stable(feature = "proc_macro_lib2", since = "1.29.0")] +pub enum Delimiter { + /// `( ... )` + #[stable(feature = "proc_macro_lib2", since = "1.29.0")] + Parenthesis, + /// `{ ... }` + #[stable(feature = "proc_macro_lib2", since = "1.29.0")] + Brace, + /// `[ ... ]` + #[stable(feature = "proc_macro_lib2", since = "1.29.0")] + 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. + #[stable(feature = "proc_macro_lib2", since = "1.29.0")] + None, +} + +impl Group { + /// 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. + #[stable(feature = "proc_macro_lib2", since = "1.29.0")] + pub fn new(delimiter: Delimiter, stream: TokenStream) -> Group { + Group(bridge::client::Group::new(delimiter, stream.0)) + } + + /// Returns the delimiter of this `Group` + #[stable(feature = "proc_macro_lib2", since = "1.29.0")] + pub fn delimiter(&self) -> Delimiter { + self.0.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. + #[stable(feature = "proc_macro_lib2", since = "1.29.0")] + pub fn stream(&self) -> TokenStream { + TokenStream(self.0.stream()) + } + + /// Returns the span for the delimiters of this token stream, spanning the + /// entire `Group`. + /// + /// ```text + /// pub fn span(&self) -> Span { + /// ^^^^^^^ + /// ``` + #[stable(feature = "proc_macro_lib2", since = "1.29.0")] + pub fn span(&self) -> Span { + Span(self.0.span()) + } + + /// Returns the span pointing to the opening delimiter of this group. + /// + /// ```text + /// pub fn span_open(&self) -> Span { + /// ^ + /// ``` + #[unstable(feature = "proc_macro_span", issue = "54725")] + pub fn span_open(&self) -> Span { + Span(self.0.span_open()) + } + + /// Returns the span pointing to the closing delimiter of this group. + /// + /// ```text + /// pub fn span_close(&self) -> Span { + /// ^ + /// ``` + #[unstable(feature = "proc_macro_span", issue = "54725")] + pub fn span_close(&self) -> Span { + Span(self.0.span_close()) + } + + /// 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`. + #[stable(feature = "proc_macro_lib2", since = "1.29.0")] + pub fn set_span(&mut self, span: Span) { + self.0.set_span(span.0); + } +} + +// N.B., the bridge only provides `to_string`, implement `fmt::Display` +// based on it (the reverse of the usual relationship between the two). +#[stable(feature = "proc_macro_lib", since = "1.15.0")] +impl ToString for Group { + fn to_string(&self) -> String { + TokenStream::from(TokenTree::from(self.clone())).to_string() + } +} + +/// 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. +#[stable(feature = "proc_macro_lib2", since = "1.29.0")] +impl fmt::Display for Group { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.write_str(&self.to_string()) + } +} + +#[stable(feature = "proc_macro_lib2", since = "1.29.0")] +impl fmt::Debug for Group { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("Group") + .field("delimiter", &self.delimiter()) + .field("stream", &self.stream()) + .field("span", &self.span()) + .finish() + } +} + +/// An `Punct` is an single punctuation character like `+`, `-` or `#`. +/// +/// Multi-character operators like `+=` are represented as two instances of `Punct` with different +/// forms of `Spacing` returned. +#[stable(feature = "proc_macro_lib2", since = "1.29.0")] +#[derive(Clone)] +pub struct Punct(bridge::client::Punct); + +#[stable(feature = "proc_macro_lib2", since = "1.29.0")] +impl !Send for Punct {} +#[stable(feature = "proc_macro_lib2", since = "1.29.0")] +impl !Sync for Punct {} + +/// Whether an `Punct` is followed immediately by another `Punct` or +/// followed by another token or whitespace. +#[derive(Copy, Clone, Debug, PartialEq, Eq)] +#[stable(feature = "proc_macro_lib2", since = "1.29.0")] +pub enum Spacing { + /// e.g., `+` is `Alone` in `+ =`, `+ident` or `+()`. + #[stable(feature = "proc_macro_lib2", since = "1.29.0")] + Alone, + /// e.g., `+` is `Joint` in `+=` or `'#`. + /// Additionally, single quote `'` can join with identifiers to form lifetimes `'ident`. + #[stable(feature = "proc_macro_lib2", since = "1.29.0")] + 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. + #[stable(feature = "proc_macro_lib2", since = "1.29.0")] + pub fn new(ch: char, spacing: Spacing) -> Punct { + Punct(bridge::client::Punct::new(ch, spacing)) + } + + /// Returns the value of this punctuation character as `char`. + #[stable(feature = "proc_macro_lib2", since = "1.29.0")] + pub fn as_char(&self) -> char { + self.0.as_char() + } + + /// 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 multi-character operator (`Joint`), or it's followed by some other token or whitespace + /// (`Alone`) so the operator has certainly ended. + #[stable(feature = "proc_macro_lib2", since = "1.29.0")] + pub fn spacing(&self) -> Spacing { + self.0.spacing() + } + + /// Returns the span for this punctuation character. + #[stable(feature = "proc_macro_lib2", since = "1.29.0")] + pub fn span(&self) -> Span { + Span(self.0.span()) + } + + /// Configure the span for this punctuation character. + #[stable(feature = "proc_macro_lib2", since = "1.29.0")] + pub fn set_span(&mut self, span: Span) { + self.0 = self.0.with_span(span.0); + } +} + +// N.B., the bridge only provides `to_string`, implement `fmt::Display` +// based on it (the reverse of the usual relationship between the two). +#[stable(feature = "proc_macro_lib", since = "1.15.0")] +impl ToString for Punct { + fn to_string(&self) -> String { + TokenStream::from(TokenTree::from(self.clone())).to_string() + } +} + +/// Prints the punctuation character as a string that should be losslessly convertible +/// back into the same character. +#[stable(feature = "proc_macro_lib2", since = "1.29.0")] +impl fmt::Display for Punct { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.write_str(&self.to_string()) + } +} + +#[stable(feature = "proc_macro_lib2", since = "1.29.0")] +impl fmt::Debug for Punct { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("Punct") + .field("ch", &self.as_char()) + .field("spacing", &self.spacing()) + .field("span", &self.span()) + .finish() + } +} + +/// An identifier (`ident`). +#[derive(Clone)] +#[stable(feature = "proc_macro_lib2", since = "1.29.0")] +pub struct Ident(bridge::client::Ident); + +impl Ident { + /// 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. + #[stable(feature = "proc_macro_lib2", since = "1.29.0")] + pub fn new(string: &str, span: Span) -> Ident { + Ident(bridge::client::Ident::new(string, span.0, false)) + } + + /// Same as `Ident::new`, but creates a raw identifier (`r#ident`). + #[unstable(feature = "proc_macro_raw_ident", issue = "54723")] + pub fn new_raw(string: &str, span: Span) -> Ident { + Ident(bridge::client::Ident::new(string, span.0, true)) + } + + /// Returns the span of this `Ident`, encompassing the entire string returned + /// by `as_str`. + #[stable(feature = "proc_macro_lib2", since = "1.29.0")] + pub fn span(&self) -> Span { + Span(self.0.span()) + } + + /// Configures the span of this `Ident`, possibly changing its hygiene context. + #[stable(feature = "proc_macro_lib2", since = "1.29.0")] + pub fn set_span(&mut self, span: Span) { + self.0 = self.0.with_span(span.0); + } +} + +// N.B., the bridge only provides `to_string`, implement `fmt::Display` +// based on it (the reverse of the usual relationship between the two). +#[stable(feature = "proc_macro_lib", since = "1.15.0")] +impl ToString for Ident { + fn to_string(&self) -> String { + TokenStream::from(TokenTree::from(self.clone())).to_string() + } +} + +/// Prints the identifier as a string that should be losslessly convertible +/// back into the same identifier. +#[stable(feature = "proc_macro_lib2", since = "1.29.0")] +impl fmt::Display for Ident { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.write_str(&self.to_string()) + } +} + +#[stable(feature = "proc_macro_lib2", since = "1.29.0")] +impl fmt::Debug for Ident { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("Ident") + .field("ident", &self.to_string()) + .field("span", &self.span()) + .finish() + } +} + +/// 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)] +#[stable(feature = "proc_macro_lib2", since = "1.29.0")] +pub struct Literal(bridge::client::Literal); + +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 round-trips 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. + #[stable(feature = "proc_macro_lib2", since = "1.29.0")] + pub fn $name(n: $kind) -> Literal { + Literal(bridge::client::Literal::typed_integer(&n.to_string(), stringify!($kind))) + } + )*) +} + +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 rountrips 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. + #[stable(feature = "proc_macro_lib2", since = "1.29.0")] + pub fn $name(n: $kind) -> Literal { + Literal(bridge::client::Literal::integer(&n.to_string())) + } + )*) +} + +impl Literal { + 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 rountrips 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. + #[stable(feature = "proc_macro_lib2", since = "1.29.0")] + pub fn f32_unsuffixed(n: f32) -> Literal { + if !n.is_finite() { + panic!("Invalid float literal {}", n); + } + Literal(bridge::client::Literal::float(&n.to_string())) + } + + /// 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 rountrips 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. + #[stable(feature = "proc_macro_lib2", since = "1.29.0")] + pub fn f32_suffixed(n: f32) -> Literal { + if !n.is_finite() { + panic!("Invalid float literal {}", n); + } + Literal(bridge::client::Literal::f32(&n.to_string())) + } + + /// 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 rountrips 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. + #[stable(feature = "proc_macro_lib2", since = "1.29.0")] + pub fn f64_unsuffixed(n: f64) -> Literal { + if !n.is_finite() { + panic!("Invalid float literal {}", n); + } + Literal(bridge::client::Literal::float(&n.to_string())) + } + + /// 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 rountrips 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. + #[stable(feature = "proc_macro_lib2", since = "1.29.0")] + pub fn f64_suffixed(n: f64) -> Literal { + if !n.is_finite() { + panic!("Invalid float literal {}", n); + } + Literal(bridge::client::Literal::f64(&n.to_string())) + } + + /// String literal. + #[stable(feature = "proc_macro_lib2", since = "1.29.0")] + pub fn string(string: &str) -> Literal { + Literal(bridge::client::Literal::string(string)) + } + + /// Character literal. + #[stable(feature = "proc_macro_lib2", since = "1.29.0")] + pub fn character(ch: char) -> Literal { + Literal(bridge::client::Literal::character(ch)) + } + + /// Byte string literal. + #[stable(feature = "proc_macro_lib2", since = "1.29.0")] + pub fn byte_string(bytes: &[u8]) -> Literal { + Literal(bridge::client::Literal::byte_string(bytes)) + } + + /// Returns the span encompassing this literal. + #[stable(feature = "proc_macro_lib2", since = "1.29.0")] + pub fn span(&self) -> Span { + Span(self.0.span()) + } + + /// Configures the span associated for this literal. + #[stable(feature = "proc_macro_lib2", since = "1.29.0")] + pub fn set_span(&mut self, span: Span) { + self.0.set_span(span.0); + } + + /// 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`. + // FIXME(SergioBenitez): check that the byte range starts and ends at a + // UTF-8 boundary of the source. otherwise, it's likely that a panic will + // occur elsewhere when the source text is printed. + // FIXME(SergioBenitez): there is no way for the user to know what + // `self.span()` actually maps to, so this method can currently only be + // called blindly. For example, `to_string()` for the character 'c' returns + // "'\u{63}'"; there is no way for the user to know whether the source text + // was 'c' or whether it was '\u{63}'. + #[unstable(feature = "proc_macro_span", issue = "54725")] + pub fn subspan<R: RangeBounds<usize>>(&self, range: R) -> Option<Span> { + // HACK(eddyb) something akin to `Option::cloned`, but for `Bound<&T>`. + fn cloned_bound<T: Clone>(bound: Bound<&T>) -> Bound<T> { + match bound { + Bound::Included(x) => Bound::Included(x.clone()), + Bound::Excluded(x) => Bound::Excluded(x.clone()), + Bound::Unbounded => Bound::Unbounded, + } + } + + self.0.subspan(cloned_bound(range.start_bound()), cloned_bound(range.end_bound())).map(Span) + } +} + +// N.B., the bridge only provides `to_string`, implement `fmt::Display` +// based on it (the reverse of the usual relationship between the two). +#[stable(feature = "proc_macro_lib", since = "1.15.0")] +impl ToString for Literal { + fn to_string(&self) -> String { + TokenStream::from(TokenTree::from(self.clone())).to_string() + } +} + +/// Prints the literal as a string that should be losslessly convertible +/// back into the same literal (except for possible rounding for floating point literals). +#[stable(feature = "proc_macro_lib2", since = "1.29.0")] +impl fmt::Display for Literal { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.write_str(&self.to_string()) + } +} + +#[stable(feature = "proc_macro_lib2", since = "1.29.0")] +impl fmt::Debug for Literal { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + self.0.fmt(f) + } +} + +/// Tracked access to environment variables. +#[unstable(feature = "proc_macro_tracked_env", issue = "74690")] +pub mod tracked_env { + use std::env::{self, VarError}; + use std::ffi::OsStr; + + /// Retrieve an environment variable and add it to build dependency info. + /// Build system executing the compiler will know that the variable was accessed during + /// compilation, and will be able to rerun the build when the value of that variable changes. + /// Besides the dependency tracking this function should be equivalent to `env::var` from the + /// standard library, except that the argument must be UTF-8. + #[unstable(feature = "proc_macro_tracked_env", issue = "74690")] + pub fn var<K: AsRef<OsStr> + AsRef<str>>(key: K) -> Result<String, VarError> { + let key: &str = key.as_ref(); + let value = env::var(key); + crate::bridge::client::FreeFunctions::track_env_var(key, value.as_deref().ok()); + value + } +} |