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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
commit | 698f8c2f01ea549d77d7dc3338a12e04c11057b9 (patch) | |
tree | 173a775858bd501c378080a10dca74132f05bc50 /library/proc_macro/src/lib.rs | |
parent | Initial commit. (diff) | |
download | rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.tar.xz rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.zip |
Adding upstream version 1.64.0+dfsg1.upstream/1.64.0+dfsg1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | library/proc_macro/src/lib.rs | 1526 |
1 files changed, 1526 insertions, 0 deletions
diff --git a/library/proc_macro/src/lib.rs b/library/proc_macro/src/lib.rs new file mode 100644 index 000000000..8e478cd7b --- /dev/null +++ b/library/proc_macro/src/lib.rs @@ -0,0 +1,1526 @@ +//! 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_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))) +)] +// This library is copied into rust-analyzer to allow loading rustc compiled proc macros. +// Please avoid unstable features where possible to minimize the amount of changes necessary +// to make it compile with rust-analyzer on stable. +#![feature(rustc_allow_const_fn_unstable)] +#![feature(staged_api)] +#![feature(allow_internal_unstable)] +#![feature(decl_macro)] +#![feature(local_key_cell_methods)] +#![feature(maybe_uninit_write_slice)] +#![feature(negative_impls)] +#![feature(new_uninit)] +#![feature(restricted_std)] +#![feature(rustc_attrs)] +#![feature(min_specialization)] +#![feature(strict_provenance)] +#![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::RangeBounds; +use std::path::PathBuf; +use std::str::FromStr; +use std::{error, fmt, iter}; + +/// 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. +#[stable(feature = "proc_macro_is_available", since = "1.57.0")] +pub fn is_available() -> bool { + bridge::client::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(Option<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")] +#[non_exhaustive] +#[derive(Debug)] +pub struct LexError; + +#[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 {} + +/// Error returned from `TokenStream::expand_expr`. +#[unstable(feature = "proc_macro_expand", issue = "90765")] +#[non_exhaustive] +#[derive(Debug)] +pub struct ExpandError; + +#[unstable(feature = "proc_macro_expand", issue = "90765")] +impl fmt::Display for ExpandError { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.write_str("macro expansion failed") + } +} + +#[unstable(feature = "proc_macro_expand", issue = "90765")] +impl error::Error for ExpandError {} + +#[unstable(feature = "proc_macro_expand", issue = "90765")] +impl !Send for ExpandError {} + +#[unstable(feature = "proc_macro_expand", issue = "90765")] +impl !Sync for ExpandError {} + +impl TokenStream { + /// Returns an empty `TokenStream` containing no token trees. + #[stable(feature = "proc_macro_lib2", since = "1.29.0")] + pub fn new() -> TokenStream { + TokenStream(None) + } + + /// Checks if this `TokenStream` is empty. + #[stable(feature = "proc_macro_lib2", since = "1.29.0")] + pub fn is_empty(&self) -> bool { + self.0.as_ref().map(|h| h.is_empty()).unwrap_or(true) + } + + /// Parses this `TokenStream` as an expression and attempts to expand any + /// macros within it. Returns the expanded `TokenStream`. + /// + /// Currently only expressions expanding to literals will succeed, although + /// this may be relaxed in the future. + /// + /// NOTE: In error conditions, `expand_expr` may leave macros unexpanded, + /// report an error, failing compilation, and/or return an `Err(..)`. The + /// specific behavior for any error condition, and what conditions are + /// considered errors, is unspecified and may change in the future. + #[unstable(feature = "proc_macro_expand", issue = "90765")] + pub fn expand_expr(&self) -> Result<TokenStream, ExpandError> { + let stream = self.0.as_ref().ok_or(ExpandError)?; + match bridge::client::TokenStream::expand_expr(stream) { + Ok(stream) => Ok(TokenStream(Some(stream))), + Err(_) => Err(ExpandError), + } + } +} + +/// 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(Some(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.as_ref().map(|t| t.to_string()).unwrap_or_default() + } +} + +/// 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}; + +fn tree_to_bridge_tree( + tree: TokenTree, +) -> bridge::TokenTree<bridge::client::TokenStream, bridge::client::Span, bridge::client::Symbol> { + 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), + } +} + +/// 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(Some(bridge::client::TokenStream::from_token_tree(tree_to_bridge_tree(tree)))) + } +} + +/// Non-generic helper for implementing `FromIterator<TokenTree>` and +/// `Extend<TokenTree>` with less monomorphization in calling crates. +struct ConcatTreesHelper { + trees: Vec< + bridge::TokenTree< + bridge::client::TokenStream, + bridge::client::Span, + bridge::client::Symbol, + >, + >, +} + +impl ConcatTreesHelper { + fn new(capacity: usize) -> Self { + ConcatTreesHelper { trees: Vec::with_capacity(capacity) } + } + + fn push(&mut self, tree: TokenTree) { + self.trees.push(tree_to_bridge_tree(tree)); + } + + fn build(self) -> TokenStream { + if self.trees.is_empty() { + TokenStream(None) + } else { + TokenStream(Some(bridge::client::TokenStream::concat_trees(None, self.trees))) + } + } + + fn append_to(self, stream: &mut TokenStream) { + if self.trees.is_empty() { + return; + } + stream.0 = Some(bridge::client::TokenStream::concat_trees(stream.0.take(), self.trees)) + } +} + +/// Non-generic helper for implementing `FromIterator<TokenStream>` and +/// `Extend<TokenStream>` with less monomorphization in calling crates. +struct ConcatStreamsHelper { + streams: Vec<bridge::client::TokenStream>, +} + +impl ConcatStreamsHelper { + fn new(capacity: usize) -> Self { + ConcatStreamsHelper { streams: Vec::with_capacity(capacity) } + } + + fn push(&mut self, stream: TokenStream) { + if let Some(stream) = stream.0 { + self.streams.push(stream); + } + } + + fn build(mut self) -> TokenStream { + if self.streams.len() <= 1 { + TokenStream(self.streams.pop()) + } else { + TokenStream(Some(bridge::client::TokenStream::concat_streams(None, self.streams))) + } + } + + fn append_to(mut self, stream: &mut TokenStream) { + if self.streams.is_empty() { + return; + } + let base = stream.0.take(); + if base.is_none() && self.streams.len() == 1 { + stream.0 = self.streams.pop(); + } else { + stream.0 = Some(bridge::client::TokenStream::concat_streams(base, self.streams)); + } + } +} + +/// 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 { + let iter = trees.into_iter(); + let mut builder = ConcatTreesHelper::new(iter.size_hint().0); + iter.for_each(|tree| builder.push(tree)); + builder.build() + } +} + +/// 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 iter = streams.into_iter(); + let mut builder = ConcatStreamsHelper::new(iter.size_hint().0); + iter.for_each(|stream| builder.push(stream)); + 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) { + let iter = trees.into_iter(); + let mut builder = ConcatTreesHelper::new(iter.size_hint().0); + iter.for_each(|tree| builder.push(tree)); + builder.append_to(self); + } +} + +#[stable(feature = "token_stream_extend", since = "1.30.0")] +impl Extend<TokenStream> for TokenStream { + fn extend<I: IntoIterator<Item = TokenStream>>(&mut self, streams: I) { + let iter = streams.into_iter(); + let mut builder = ConcatStreamsHelper::new(iter.size_hint().0); + iter.for_each(|stream| builder.push(stream)); + builder.append_to(self); + } +} + +/// 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( + std::vec::IntoIter< + bridge::TokenTree< + bridge::client::TokenStream, + bridge::client::Span, + bridge::client::Symbol, + >, + >, + ); + + #[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)), + }) + } + + fn size_hint(&self) -> (usize, Option<usize>) { + self.0.size_hint() + } + + fn count(self) -> usize { + self.0.count() + } + } + + #[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.map(|v| v.into_trees()).unwrap_or_default().into_iter()) + } + } +} + +/// `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")]`. +/// +/// 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, proc_macro_internals)] +#[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().add_1_to_column() + } + + /// 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().add_1_to_column() + } + + /// Creates an empty span pointing to directly before this span. + #[unstable(feature = "proc_macro_span_shrink", issue = "87552")] + pub fn before(&self) -> Span { + Span(self.0.before()) + } + + /// Creates an empty span pointing to directly after this span. + #[unstable(feature = "proc_macro_span_shrink", issue = "87552")] + pub fn after(&self) -> Span { + Span(self.0.after()) + } + + /// 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() + } + + // Used by the implementation of `Span::quote` + #[doc(hidden)] + #[unstable(feature = "proc_macro_internals", issue = "27812")] + pub fn save_span(&self) -> usize { + self.0.save_span() + } + + // Used by the implementation of `Span::quote` + #[doc(hidden)] + #[unstable(feature = "proc_macro_internals", issue = "27812")] + pub fn recover_proc_macro_span(id: usize) -> Span { + Span(bridge::client::Span::recover_proc_macro_span(id)) + } + + 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 1-indexed column (number of bytes in UTF-8 encoding) in the source + /// file on which the span starts or ends (inclusive). + #[unstable(feature = "proc_macro_span", issue = "54725")] + pub column: usize, +} + +impl LineColumn { + fn add_1_to_column(self) -> Self { + LineColumn { line: self.line, column: self.column + 1 } + } +} + +#[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 might 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 might not actually be valid. + /// + /// [`is_real`]: Self::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::Group<bridge::client::TokenStream, bridge::client::Span>); + +#[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 invisible 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`. + /// Invisible delimiters might 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::Group { + delimiter, + stream: stream.0, + span: bridge::DelimSpan::from_single(Span::call_site().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.clone()) + } + + /// 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.entire) + } + + /// Returns the span pointing to the opening delimiter of this group. + /// + /// ```text + /// pub fn span_open(&self) -> Span { + /// ^ + /// ``` + #[stable(feature = "proc_macro_group_span", since = "1.55.0")] + 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 { + /// ^ + /// ``` + #[stable(feature = "proc_macro_group_span", since = "1.55.0")] + 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.span = bridge::DelimSpan::from_single(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() + } +} + +/// A `Punct` is a single punctuation character such as `+`, `-` 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::Punct<bridge::client::Span>); + +#[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 {} + +/// Describes whether a `Punct` is followed immediately by another `Punct` ([`Spacing::Joint`]) or +/// by a different token or whitespace ([`Spacing::Alone`]). +#[derive(Copy, Clone, Debug, PartialEq, Eq)] +#[stable(feature = "proc_macro_lib2", since = "1.29.0")] +pub enum Spacing { + /// A `Punct` is not immediately followed by another `Punct`. + /// E.g. `+` is `Alone` in `+ =`, `+ident` and `+()`. + #[stable(feature = "proc_macro_lib2", since = "1.29.0")] + Alone, + /// A `Punct` is immediately followed by another `Punct`. + /// E.g. `+` is `Joint` in `+=` and `++`. + /// + /// 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 { + const LEGAL_CHARS: &[char] = &[ + '=', '<', '>', '!', '~', '+', '-', '*', '/', '%', '^', '&', '|', '@', '.', ',', ';', + ':', '#', '$', '?', '\'', + ]; + if !LEGAL_CHARS.contains(&ch) { + panic!("unsupported character `{:?}`", ch); + } + Punct(bridge::Punct { + ch: ch as u8, + joint: spacing == Spacing::Joint, + span: Span::call_site().0, + }) + } + + /// 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.ch 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 { + if self.0.joint { Spacing::Joint } else { Spacing::Alone } + } + + /// 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.span = span.0; + } +} + +#[stable(feature = "proc_macro_lib2", since = "1.29.0")] +impl ToString for Punct { + fn to_string(&self) -> String { + self.as_char().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 { + write!(f, "{}", self.as_char()) + } +} + +#[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() + } +} + +#[stable(feature = "proc_macro_punct_eq", since = "1.50.0")] +impl PartialEq<char> for Punct { + fn eq(&self, rhs: &char) -> bool { + self.as_char() == *rhs + } +} + +#[stable(feature = "proc_macro_punct_eq_flipped", since = "1.52.0")] +impl PartialEq<Punct> for char { + fn eq(&self, rhs: &Punct) -> bool { + *self == rhs.as_char() + } +} + +/// An identifier (`ident`). +#[derive(Clone)] +#[stable(feature = "proc_macro_lib2", since = "1.29.0")] +pub struct Ident(bridge::Ident<bridge::client::Span, bridge::client::Symbol>); + +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 (including keywords, e.g. `self` or `fn`). 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::Ident { + sym: bridge::client::Symbol::new_ident(string, false), + is_raw: false, + span: span.0, + }) + } + + /// Same as `Ident::new`, but creates a raw identifier (`r#ident`). + /// The `string` argument 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. + #[stable(feature = "proc_macro_raw_ident", since = "1.47.0")] + pub fn new_raw(string: &str, span: Span) -> Ident { + Ident(bridge::Ident { + sym: bridge::client::Symbol::new_ident(string, true), + is_raw: true, + span: span.0, + }) + } + + /// Returns the span of this `Ident`, encompassing the entire string returned + /// by [`to_string`](ToString::to_string). + #[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.span = span.0; + } +} + +/// Converts the identifier to a string that should be losslessly convertible +/// back into the same identifier. +#[stable(feature = "proc_macro_lib2", since = "1.29.0")] +impl ToString for Ident { + fn to_string(&self) -> String { + self.0.sym.with(|sym| if self.0.is_raw { ["r#", sym].concat() } else { sym.to_owned() }) + } +} + +/// 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 { + if self.0.is_raw { + f.write_str("r#")?; + } + fmt::Display::fmt(&self.0.sym, f) + } +} + +#[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::Literal<bridge::client::Span, bridge::client::Symbol>); + +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 might 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: $kind) -> Literal { + Literal(bridge::Literal { + kind: bridge::LitKind::Integer, + symbol: bridge::client::Symbol::new(&n.to_string()), + suffix: Some(bridge::client::Symbol::new(stringify!($kind))), + span: Span::call_site().0, + }) + } + )*) +} + +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 might 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::Literal { + kind: bridge::LitKind::Integer, + symbol: bridge::client::Symbol::new(&n.to_string()), + suffix: None, + span: Span::call_site().0, + }) + } + )*) +} + +impl Literal { + fn new(kind: bridge::LitKind, value: &str, suffix: Option<&str>) -> Self { + Literal(bridge::Literal { + kind, + symbol: bridge::client::Symbol::new(value), + suffix: suffix.map(bridge::client::Symbol::new), + span: Span::call_site().0, + }) + } + + 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 might 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}"); + } + let mut repr = n.to_string(); + if !repr.contains('.') { + repr.push_str(".0"); + } + Literal::new(bridge::LitKind::Float, &repr, None) + } + + /// 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 might 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::new(bridge::LitKind::Float, &n.to_string(), Some("f32")) + } + + /// 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 might 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}"); + } + let mut repr = n.to_string(); + if !repr.contains('.') { + repr.push_str(".0"); + } + Literal::new(bridge::LitKind::Float, &repr, None) + } + + /// 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 might 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::new(bridge::LitKind::Float, &n.to_string(), Some("f64")) + } + + /// String literal. + #[stable(feature = "proc_macro_lib2", since = "1.29.0")] + pub fn string(string: &str) -> Literal { + let quoted = format!("{:?}", string); + assert!(quoted.starts_with('"') && quoted.ends_with('"')); + let symbol = "ed[1..quoted.len() - 1]; + Literal::new(bridge::LitKind::Str, symbol, None) + } + + /// Character literal. + #[stable(feature = "proc_macro_lib2", since = "1.29.0")] + pub fn character(ch: char) -> Literal { + let quoted = format!("{:?}", ch); + assert!(quoted.starts_with('\'') && quoted.ends_with('\'')); + let symbol = "ed[1..quoted.len() - 1]; + Literal::new(bridge::LitKind::Char, symbol, None) + } + + /// Byte string literal. + #[stable(feature = "proc_macro_lib2", since = "1.29.0")] + pub fn byte_string(bytes: &[u8]) -> Literal { + let string = bytes + .iter() + .cloned() + .flat_map(std::ascii::escape_default) + .map(Into::<char>::into) + .collect::<String>(); + Literal::new(bridge::LitKind::ByteStr, &string, None) + } + + /// 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.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> { + self.0.span.subspan(range.start_bound().cloned(), range.end_bound().cloned()).map(Span) + } + + fn with_symbol_and_suffix<R>(&self, f: impl FnOnce(&str, &str) -> R) -> R { + self.0.symbol.with(|symbol| match self.0.suffix { + Some(suffix) => suffix.with(|suffix| f(symbol, suffix)), + None => f(symbol, ""), + }) + } + + /// Invokes the callback with a `&[&str]` consisting of each part of the + /// literal's representation. This is done to allow the `ToString` and + /// `Display` implementations to borrow references to symbol values, and + /// both be optimized to reduce overhead. + fn with_stringify_parts<R>(&self, f: impl FnOnce(&[&str]) -> R) -> R { + /// Returns a string containing exactly `num` '#' characters. + /// Uses a 256-character source string literal which is always safe to + /// index with a `u8` index. + fn get_hashes_str(num: u8) -> &'static str { + const HASHES: &str = "\ + ################################################################\ + ################################################################\ + ################################################################\ + ################################################################\ + "; + const _: () = assert!(HASHES.len() == 256); + &HASHES[..num as usize] + } + + self.with_symbol_and_suffix(|symbol, suffix| match self.0.kind { + bridge::LitKind::Byte => f(&["b'", symbol, "'", suffix]), + bridge::LitKind::Char => f(&["'", symbol, "'", suffix]), + bridge::LitKind::Str => f(&["\"", symbol, "\"", suffix]), + bridge::LitKind::StrRaw(n) => { + let hashes = get_hashes_str(n); + f(&["r", hashes, "\"", symbol, "\"", hashes, suffix]) + } + bridge::LitKind::ByteStr => f(&["b\"", symbol, "\"", suffix]), + bridge::LitKind::ByteStrRaw(n) => { + let hashes = get_hashes_str(n); + f(&["br", hashes, "\"", symbol, "\"", hashes, suffix]) + } + _ => f(&[symbol, suffix]), + }) + } +} + +/// Parse a single literal from its stringified representation. +/// +/// In order to parse successfully, the input string must not contain anything +/// but the literal token. Specifically, it must not contain whitespace or +/// comments in addition to the literal. +/// +/// The resulting literal token will have a `Span::call_site()` span. +/// +/// 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_literal_parse", since = "1.54.0")] +impl FromStr for Literal { + type Err = LexError; + + fn from_str(src: &str) -> Result<Self, LexError> { + match bridge::client::FreeFunctions::literal_from_str(src) { + Ok(literal) => Ok(Literal(literal)), + Err(()) => Err(LexError), + } + } +} + +#[stable(feature = "proc_macro_lib2", since = "1.29.0")] +impl ToString for Literal { + fn to_string(&self) -> String { + self.with_stringify_parts(|parts| parts.concat()) + } +} + +/// 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 { + self.with_stringify_parts(|parts| { + for part in parts { + fmt::Display::fmt(part, f)?; + } + Ok(()) + }) + } +} + +#[stable(feature = "proc_macro_lib2", since = "1.29.0")] +impl fmt::Debug for Literal { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("Literal") + // format the kind on one line even in {:#?} mode + .field("kind", &format_args!("{:?}", &self.0.kind)) + .field("symbol", &self.0.symbol) + // format `Some("...")` on one line even in {:#?} mode + .field("suffix", &format_args!("{:?}", &self.0.suffix)) + .field("span", &self.0.span) + .finish() + } +} + +/// Tracked access to environment variables. +#[unstable(feature = "proc_macro_tracked_env", issue = "99515")] +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 = "99515")] + 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 + } +} + +/// Tracked access to additional files. +#[unstable(feature = "track_path", issue = "99515")] +pub mod tracked_path { + + /// Track a file explicitly. + /// + /// Commonly used for tracking asset preprocessing. + #[unstable(feature = "track_path", issue = "99515")] + pub fn path<P: AsRef<str>>(path: P) { + let path: &str = path.as_ref(); + crate::bridge::client::FreeFunctions::track_path(path); + } +} |