//! lib-proc-macro main module //! //! Copy from https://github.com/rust-lang/rust/blob/6050e523bae6de61de4e060facc43dc512adaccd/src/libproc_macro/lib.rs //! augmented with removing unstable features // NOTE(@edwin0cheng): // Because we just copy the bridge module from rustc for ABI compatible // There are some unused stuffs inside it. // We suppress these warning here. #[doc(hidden)] #[allow(unused_macros)] #[allow(unused_variables)] pub mod bridge; mod diagnostic; pub use diagnostic::{Diagnostic, Level, MultiSpan}; use std::ops::{Bound, RangeBounds}; use std::path::PathBuf; use std::str::FromStr; use std::{fmt, iter, mem}; /// 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. #[derive(Clone)] pub struct TokenStream(bridge::client::TokenStream); /// Error returned from `TokenStream::from_str` #[derive(Debug)] pub struct LexError { _inner: (), } impl TokenStream { /// Returns an empty `TokenStream` containing no token trees. pub fn new() -> TokenStream { TokenStream(bridge::client::TokenStream::new()) } /// Checks if this `TokenStream` is empty. 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. 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). // 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. 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. 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() } } /// Creates a token stream containing a single token tree. 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. 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. 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()) } } impl Extend<TokenTree> for TokenStream { fn extend<I: IntoIterator<Item = TokenTree>>(&mut self, trees: I) { self.extend(trees.into_iter().map(TokenStream::from)); } } 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. pub mod token_stream { use crate::proc_macro::{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)] pub struct IntoIter(bridge::client::TokenStreamIter); 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)), }) } } impl IntoIterator for TokenStream { type Item = TokenTree; type IntoIter = IntoIter; fn into_iter(self) -> IntoIter { IntoIter(self.0.into_iter()) } } } /// A region of source code, along with macro expansion information. #[derive(Copy, Clone)] pub struct Span(bridge::client::Span); macro_rules! diagnostic_method { ($name:ident, $level:expr) => { /// Creates a new `Diagnostic` with the given `message` at the span /// `self`. pub fn $name<T: Into<String>>(self, message: T) -> Diagnostic { Diagnostic::spanned(self, $level, message) } }; } impl Span { /// A span that resolves at the macro definition site. pub fn def_site() -> Span { Span(bridge::client::Span::def_site()) } /// The span of the invocation of the current procedural macro. /// Identifiers created with this span will be resolved as if they were written /// directly at the macro call location (call-site hygiene) and other code /// at the macro call site will be able to refer to them as well. pub fn call_site() -> Span { Span(bridge::client::Span::call_site()) } /// A span that represents `macro_rules` hygiene, and sometimes resolves at the macro /// definition site (local variables, labels, `$crate`) and sometimes at the macro /// call site (everything else). /// The span location is taken from the call-site. pub fn mixed_site() -> Span { Span(bridge::client::Span::mixed_site()) } /// The original source file into which this span points. 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. 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`. pub fn source(&self) -> Span { Span(self.0.source()) } /// Gets the starting line/column in the source file for this span. pub fn start(&self) -> LineColumn { self.0.start() } /// Gets the ending line/column in the source file for this span. 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. 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`. 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`. pub fn located_at(&self, other: Span) -> Span { other.resolved_at(*self) } /// Compares to spans to see if they're equal. 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. 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. 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`. #[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). pub line: usize, /// The 0-indexed column (in UTF-8 characters) in the source file on which /// the span starts or ends (inclusive). pub column: usize, } /// The source file of a given `Span`. #[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 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. 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() } } 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() } } impl PartialEq for SourceFile { fn eq(&self, other: &Self) -> bool { self.0.eq(&other.0) } } impl Eq for SourceFile {} /// A single token or a delimited sequence of token trees (e.g., `[1, (), ..]`). #[derive(Clone)] pub enum TokenTree { /// A token stream surrounded by bracket delimiters. Group(Group), /// An identifier. Ident(Ident), /// A single punctuation character (`+`, `,`, `$`, etc.). Punct(Punct), /// A literal character (`'a'`), string (`"hello"`), number (`2.3`), etc. Literal(Literal), } impl TokenTree { /// Returns the span of this tree, delegating to the `span` method of /// the contained token or a delimited stream. pub fn span(&self) -> Span { match *self { TokenTree::Group(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. 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. 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), } } } impl From<Group> for TokenTree { fn from(g: Group) -> TokenTree { TokenTree::Group(g) } } impl From<Ident> for TokenTree { fn from(g: Ident) -> TokenTree { TokenTree::Ident(g) } } impl From<Punct> for TokenTree { fn from(g: Punct) -> TokenTree { TokenTree::Punct(g) } } 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). // 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. 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)] pub struct Group(bridge::client::Group); /// Describes how a sequence of token trees is delimited. #[derive(Copy, Clone, Debug, PartialEq, Eq)] pub enum Delimiter { /// `( ... )` Parenthesis, /// `{ ... }` Brace, /// `[ ... ]` Bracket, /// `Ø ... Ø` /// An implicit delimiter, that may, for example, appear around tokens coming from a /// "macro variable" `$var`. It is important to preserve operator priorities in cases like /// `$var * 3` where `$var` is `1 + 2`. /// Implicit delimiters may not survive roundtrip of a token stream through a string. None, } impl Group { /// Creates a new `Group` with the given delimiter and token stream. /// /// This constructor will set the span for this group to /// `Span::call_site()`. To change the span you can use the `set_span` /// method below. pub fn new(delimiter: Delimiter, stream: TokenStream) -> Group { Group(bridge::client::Group::new(delimiter, stream.0)) } /// Returns the delimiter of this `Group` 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. 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 { /// ^^^^^^^ /// ``` 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 { /// ^ /// ``` 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 { /// ^ /// ``` 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`. 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). // 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. impl fmt::Display for Group { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { f.write_str(&self.to_string()) } } 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. #[derive(Clone)] pub struct Punct(bridge::client::Punct); /// Whether an `Punct` is followed immediately by another `Punct` or /// followed by another token or whitespace. #[derive(Copy, Clone, Debug, PartialEq, Eq)] pub enum Spacing { /// e.g., `+` is `Alone` in `+ =`, `+ident` or `+()`. Alone, /// e.g., `+` is `Joint` in `+=` or `'#`. /// Additionally, single quote `'` can join with identifiers to form lifetimes `'ident`. Joint, } impl Punct { /// Creates a new `Punct` from the given character and spacing. /// The `ch` argument must be a valid punctuation character permitted by the language, /// otherwise the function will panic. /// /// The returned `Punct` will have the default span of `Span::call_site()` /// which can be further configured with the `set_span` method below. pub fn new(ch: char, spacing: Spacing) -> Punct { Punct(bridge::client::Punct::new(ch, spacing)) } /// Returns the value of this punctuation character as `char`. 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. pub fn spacing(&self) -> Spacing { self.0.spacing() } /// Returns the span for this punctuation character. pub fn span(&self) -> Span { Span(self.0.span()) } /// Configure the span for this punctuation character. 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). // 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. impl fmt::Display for Punct { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { f.write_str(&self.to_string()) } } 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, PartialEq, Eq, Hash)] 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. 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`). 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`. pub fn span(&self) -> Span { Span(self.0.span()) } /// Configures the span of this `Ident`, possibly changing its hygiene context. 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). // 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. impl fmt::Display for Ident { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { f.write_str(&self.to_string()) } } 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)] 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. 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. 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. 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. 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. 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. 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. pub fn string(string: &str) -> Literal { Literal(bridge::client::Literal::string(string)) } /// Character literal. pub fn character(ch: char) -> Literal { Literal(bridge::client::Literal::character(ch)) } /// Byte string literal. pub fn byte_string(bytes: &[u8]) -> Literal { Literal(bridge::client::Literal::byte_string(bytes)) } /// Returns the span encompassing this literal. pub fn span(&self) -> Span { Span(self.0.span()) } /// Configures the span associated for this literal. 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}'. 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). // 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). impl fmt::Display for Literal { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { f.write_str(&self.to_string()) } } impl fmt::Debug for Literal { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { // FIXME(eddyb) `Literal` should not expose internal `Debug` impls. self.0.fmt(f) } }