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Diffstat (limited to 'quote/src/runtime.rs')
| -rw-r--r-- | quote/src/runtime.rs | 373 |
1 files changed, 373 insertions, 0 deletions
diff --git a/quote/src/runtime.rs b/quote/src/runtime.rs new file mode 100644 index 0000000..4a1c14c --- /dev/null +++ b/quote/src/runtime.rs @@ -0,0 +1,373 @@ +use crate::{IdentFragment, ToTokens, TokenStreamExt}; +use std::fmt; +use std::ops::BitOr; + +pub use proc_macro2::*; + +pub struct HasIterator; // True +pub struct ThereIsNoIteratorInRepetition; // False + +impl BitOr<ThereIsNoIteratorInRepetition> for ThereIsNoIteratorInRepetition { + type Output = ThereIsNoIteratorInRepetition; + fn bitor(self, _rhs: ThereIsNoIteratorInRepetition) -> ThereIsNoIteratorInRepetition { + ThereIsNoIteratorInRepetition + } +} + +impl BitOr<ThereIsNoIteratorInRepetition> for HasIterator { + type Output = HasIterator; + fn bitor(self, _rhs: ThereIsNoIteratorInRepetition) -> HasIterator { + HasIterator + } +} + +impl BitOr<HasIterator> for ThereIsNoIteratorInRepetition { + type Output = HasIterator; + fn bitor(self, _rhs: HasIterator) -> HasIterator { + HasIterator + } +} + +impl BitOr<HasIterator> for HasIterator { + type Output = HasIterator; + fn bitor(self, _rhs: HasIterator) -> HasIterator { + HasIterator + } +} + +/// Extension traits used by the implementation of `quote!`. These are defined +/// in separate traits, rather than as a single trait due to ambiguity issues. +/// +/// These traits expose a `quote_into_iter` method which should allow calling +/// whichever impl happens to be applicable. Calling that method repeatedly on +/// the returned value should be idempotent. +pub mod ext { + use super::RepInterp; + use super::{HasIterator as HasIter, ThereIsNoIteratorInRepetition as DoesNotHaveIter}; + use crate::ToTokens; + use std::collections::btree_set::{self, BTreeSet}; + use std::slice; + + /// Extension trait providing the `quote_into_iter` method on iterators. + pub trait RepIteratorExt: Iterator + Sized { + fn quote_into_iter(self) -> (Self, HasIter) { + (self, HasIter) + } + } + + impl<T: Iterator> RepIteratorExt for T {} + + /// Extension trait providing the `quote_into_iter` method for + /// non-iterable types. These types interpolate the same value in each + /// iteration of the repetition. + pub trait RepToTokensExt { + /// Pretend to be an iterator for the purposes of `quote_into_iter`. + /// This allows repeated calls to `quote_into_iter` to continue + /// correctly returning DoesNotHaveIter. + fn next(&self) -> Option<&Self> { + Some(self) + } + + fn quote_into_iter(&self) -> (&Self, DoesNotHaveIter) { + (self, DoesNotHaveIter) + } + } + + impl<T: ToTokens + ?Sized> RepToTokensExt for T {} + + /// Extension trait providing the `quote_into_iter` method for types that + /// can be referenced as an iterator. + pub trait RepAsIteratorExt<'q> { + type Iter: Iterator; + + fn quote_into_iter(&'q self) -> (Self::Iter, HasIter); + } + + impl<'q, 'a, T: RepAsIteratorExt<'q> + ?Sized> RepAsIteratorExt<'q> for &'a T { + type Iter = T::Iter; + + fn quote_into_iter(&'q self) -> (Self::Iter, HasIter) { + <T as RepAsIteratorExt>::quote_into_iter(*self) + } + } + + impl<'q, 'a, T: RepAsIteratorExt<'q> + ?Sized> RepAsIteratorExt<'q> for &'a mut T { + type Iter = T::Iter; + + fn quote_into_iter(&'q self) -> (Self::Iter, HasIter) { + <T as RepAsIteratorExt>::quote_into_iter(*self) + } + } + + impl<'q, T: 'q> RepAsIteratorExt<'q> for [T] { + type Iter = slice::Iter<'q, T>; + + fn quote_into_iter(&'q self) -> (Self::Iter, HasIter) { + (self.iter(), HasIter) + } + } + + impl<'q, T: 'q> RepAsIteratorExt<'q> for Vec<T> { + type Iter = slice::Iter<'q, T>; + + fn quote_into_iter(&'q self) -> (Self::Iter, HasIter) { + (self.iter(), HasIter) + } + } + + impl<'q, T: 'q> RepAsIteratorExt<'q> for BTreeSet<T> { + type Iter = btree_set::Iter<'q, T>; + + fn quote_into_iter(&'q self) -> (Self::Iter, HasIter) { + (self.iter(), HasIter) + } + } + + macro_rules! array_rep_slice { + ($($l:tt)*) => { + $( + impl<'q, T: 'q> RepAsIteratorExt<'q> for [T; $l] { + type Iter = slice::Iter<'q, T>; + + fn quote_into_iter(&'q self) -> (Self::Iter, HasIter) { + (self.iter(), HasIter) + } + } + )* + } + } + + array_rep_slice!( + 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 + 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 + ); + + impl<'q, T: RepAsIteratorExt<'q>> RepAsIteratorExt<'q> for RepInterp<T> { + type Iter = T::Iter; + + fn quote_into_iter(&'q self) -> (Self::Iter, HasIter) { + self.0.quote_into_iter() + } + } +} + +// Helper type used within interpolations to allow for repeated binding names. +// Implements the relevant traits, and exports a dummy `next()` method. +#[derive(Copy, Clone)] +pub struct RepInterp<T>(pub T); + +impl<T> RepInterp<T> { + // This method is intended to look like `Iterator::next`, and is called when + // a name is bound multiple times, as the previous binding will shadow the + // original `Iterator` object. This allows us to avoid advancing the + // iterator multiple times per iteration. + pub fn next(self) -> Option<T> { + Some(self.0) + } +} + +impl<T: Iterator> Iterator for RepInterp<T> { + type Item = T::Item; + + fn next(&mut self) -> Option<Self::Item> { + self.0.next() + } +} + +impl<T: ToTokens> ToTokens for RepInterp<T> { + fn to_tokens(&self, tokens: &mut TokenStream) { + self.0.to_tokens(tokens); + } +} + +fn is_ident_start(c: u8) -> bool { + (b'a' <= c && c <= b'z') || (b'A' <= c && c <= b'Z') || c == b'_' +} + +fn is_ident_continue(c: u8) -> bool { + (b'a' <= c && c <= b'z') || (b'A' <= c && c <= b'Z') || c == b'_' || (b'0' <= c && c <= b'9') +} + +fn is_ident(token: &str) -> bool { + let mut iter = token.bytes(); + let first_ok = iter.next().map(is_ident_start).unwrap_or(false); + + first_ok && iter.all(is_ident_continue) +} + +pub fn parse(tokens: &mut TokenStream, span: Span, s: &str) { + if is_ident(s) { + // Fast path, since idents are the most common token. + tokens.append(Ident::new(s, span)); + } else { + let s: TokenStream = s.parse().expect("invalid token stream"); + tokens.extend(s.into_iter().map(|mut t| { + t.set_span(span); + t + })); + } +} + +macro_rules! push_punct { + ($name:ident $char1:tt) => { + pub fn $name(tokens: &mut TokenStream, span: Span) { + let mut punct = Punct::new($char1, Spacing::Alone); + punct.set_span(span); + tokens.append(punct); + } + }; + ($name:ident $char1:tt $char2:tt) => { + pub fn $name(tokens: &mut TokenStream, span: Span) { + let mut punct = Punct::new($char1, Spacing::Joint); + punct.set_span(span); + tokens.append(punct); + let mut punct = Punct::new($char2, Spacing::Alone); + punct.set_span(span); + tokens.append(punct); + } + }; + ($name:ident $char1:tt $char2:tt $char3:tt) => { + pub fn $name(tokens: &mut TokenStream, span: Span) { + let mut punct = Punct::new($char1, Spacing::Joint); + punct.set_span(span); + tokens.append(punct); + let mut punct = Punct::new($char2, Spacing::Joint); + punct.set_span(span); + tokens.append(punct); + let mut punct = Punct::new($char3, Spacing::Alone); + punct.set_span(span); + tokens.append(punct); + } + }; +} + +push_punct!(push_add '+'); +push_punct!(push_add_eq '+' '='); +push_punct!(push_and '&'); +push_punct!(push_and_and '&' '&'); +push_punct!(push_and_eq '&' '='); +push_punct!(push_at '@'); +push_punct!(push_bang '!'); +push_punct!(push_caret '^'); +push_punct!(push_caret_eq '^' '='); +push_punct!(push_colon ':'); +push_punct!(push_colon2 ':' ':'); +push_punct!(push_comma ','); +push_punct!(push_div '/'); +push_punct!(push_div_eq '/' '='); +push_punct!(push_dot '.'); +push_punct!(push_dot2 '.' '.'); +push_punct!(push_dot3 '.' '.' '.'); +push_punct!(push_dot_dot_eq '.' '.' '='); +push_punct!(push_eq '='); +push_punct!(push_eq_eq '=' '='); +push_punct!(push_ge '>' '='); +push_punct!(push_gt '>'); +push_punct!(push_le '<' '='); +push_punct!(push_lt '<'); +push_punct!(push_mul_eq '*' '='); +push_punct!(push_ne '!' '='); +push_punct!(push_or '|'); +push_punct!(push_or_eq '|' '='); +push_punct!(push_or_or '|' '|'); +push_punct!(push_pound '#'); +push_punct!(push_question '?'); +push_punct!(push_rarrow '-' '>'); +push_punct!(push_larrow '<' '-'); +push_punct!(push_rem '%'); +push_punct!(push_rem_eq '%' '='); +push_punct!(push_fat_arrow '=' '>'); +push_punct!(push_semi ';'); +push_punct!(push_shl '<' '<'); +push_punct!(push_shl_eq '<' '<' '='); +push_punct!(push_shr '>' '>'); +push_punct!(push_shr_eq '>' '>' '='); +push_punct!(push_star '*'); +push_punct!(push_sub '-'); +push_punct!(push_sub_eq '-' '='); + +// Helper method for constructing identifiers from the `format_ident!` macro, +// handling `r#` prefixes. +// +// Directly parsing the input string may produce a valid identifier, +// although the input string was invalid, due to ignored characters such as +// whitespace and comments. Instead, we always create a non-raw identifier +// to validate that the string is OK, and only parse again if needed. +// +// The `is_ident` method defined above is insufficient for validation, as it +// will reject non-ASCII identifiers. +pub fn mk_ident(id: &str, span: Option<Span>) -> Ident { + let span = span.unwrap_or_else(Span::call_site); + + let is_raw = id.starts_with("r#"); + let unraw = Ident::new(if is_raw { &id[2..] } else { id }, span); + if !is_raw { + return unraw; + } + + // At this point, the identifier is raw, and the unraw-ed version of it was + // successfully converted into an identifier. Try to produce a valid raw + // identifier by running the `TokenStream` parser, and unwrapping the first + // token as an `Ident`. + // + // FIXME: When `Ident::new_raw` becomes stable, this method should be + // updated to call it when available. + match id.parse::<TokenStream>() { + Ok(ts) => { + let mut iter = ts.into_iter(); + match (iter.next(), iter.next()) { + (Some(TokenTree::Ident(mut id)), None) => { + id.set_span(span); + id + } + _ => unreachable!("valid raw ident fails to parse"), + } + } + Err(_) => unreachable!("valid raw ident fails to parse"), + } +} + +// Adapts from `IdentFragment` to `fmt::Display` for use by the `format_ident!` +// macro, and exposes span information from these fragments. +// +// This struct also has forwarding implementations of the formatting traits +// `Octal`, `LowerHex`, `UpperHex`, and `Binary` to allow for their use within +// `format_ident!`. +#[derive(Copy, Clone)] +pub struct IdentFragmentAdapter<T: IdentFragment>(pub T); + +impl<T: IdentFragment> IdentFragmentAdapter<T> { + pub fn span(&self) -> Option<Span> { + self.0.span() + } +} + +impl<T: IdentFragment> fmt::Display for IdentFragmentAdapter<T> { + fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { + IdentFragment::fmt(&self.0, f) + } +} + +impl<T: IdentFragment + fmt::Octal> fmt::Octal for IdentFragmentAdapter<T> { + fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { + fmt::Octal::fmt(&self.0, f) + } +} + +impl<T: IdentFragment + fmt::LowerHex> fmt::LowerHex for IdentFragmentAdapter<T> { + fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { + fmt::LowerHex::fmt(&self.0, f) + } +} + +impl<T: IdentFragment + fmt::UpperHex> fmt::UpperHex for IdentFragmentAdapter<T> { + fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { + fmt::UpperHex::fmt(&self.0, f) + } +} + +impl<T: IdentFragment + fmt::Binary> fmt::Binary for IdentFragmentAdapter<T> { + fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { + fmt::Binary::fmt(&self.0, f) + } +} |