2016-06-29 13:55:10 -05:00
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//! # Token Streams
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//!
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2017-05-12 13:05:39 -05:00
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//! `TokenStream`s represent syntactic objects before they are converted into ASTs.
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2016-06-29 13:55:10 -05:00
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//! A `TokenStream` is, roughly speaking, a sequence (eg stream) of `TokenTree`s,
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2017-01-29 02:38:44 -06:00
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//! which are themselves a single `Token` or a `Delimited` subsequence of tokens.
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2016-06-29 13:55:10 -05:00
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//!
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2016-07-19 17:50:34 -05:00
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//! ## Ownership
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//!
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2019-09-05 21:56:45 -05:00
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//! `TokenStream`s are persistent data structures constructed as ropes with reference
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2017-05-12 13:05:39 -05:00
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//! counted-children. In general, this means that calling an operation on a `TokenStream`
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//! (such as `slice`) produces an entirely new `TokenStream` from the borrowed reference to
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//! the original. This essentially coerces `TokenStream`s into 'views' of their subparts,
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//! and a borrowed `TokenStream` is sufficient to build an owned `TokenStream` without taking
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2016-07-19 17:50:34 -05:00
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//! ownership of the original.
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2016-06-20 10:49:33 -05:00
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2019-10-11 05:46:32 -05:00
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use crate::token::{self, DelimToken, Token, TokenKind};
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2019-02-06 11:33:01 -06:00
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2019-11-03 05:58:01 -06:00
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use syntax_pos::{Span, DUMMY_SP};
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2019-02-06 11:33:01 -06:00
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#[cfg(target_arch = "x86_64")]
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2019-05-19 05:59:44 -05:00
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use rustc_data_structures::static_assert_size;
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2018-12-11 16:01:39 -06:00
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use rustc_data_structures::sync::Lrc;
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2019-03-27 20:27:26 -05:00
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use smallvec::{SmallVec, smallvec};
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2016-06-29 13:55:10 -05:00
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2019-10-08 18:45:40 -05:00
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use std::{iter, mem};
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2016-07-04 05:25:50 -05:00
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2019-08-01 16:26:40 -05:00
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#[cfg(test)]
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mod tests;
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2016-06-20 10:49:33 -05:00
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/// When the main rust parser encounters a syntax-extension invocation, it
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/// parses the arguments to the invocation as a token-tree. This is a very
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/// loose structure, such that all sorts of different AST-fragments can
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/// be passed to syntax extensions using a uniform type.
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///
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/// If the syntax extension is an MBE macro, it will attempt to match its
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/// LHS token tree against the provided token tree, and if it finds a
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/// match, will transcribe the RHS token tree, splicing in any captured
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2017-05-12 13:05:39 -05:00
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/// `macro_parser::matched_nonterminals` into the `SubstNt`s it finds.
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2016-06-20 10:49:33 -05:00
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///
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/// The RHS of an MBE macro is the only place `SubstNt`s are substituted.
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/// Nothing special happens to misnamed or misplaced `SubstNt`s.
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2018-06-26 16:57:27 -05:00
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#[derive(Debug, Clone, PartialEq, RustcEncodable, RustcDecodable)]
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2016-06-20 10:49:33 -05:00
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pub enum TokenTree {
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/// A single token
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2019-06-04 12:42:43 -05:00
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Token(Token),
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2016-06-20 10:49:33 -05:00
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/// A delimited sequence of token trees
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2019-01-08 23:53:14 -06:00
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Delimited(DelimSpan, DelimToken, TokenStream),
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2016-06-20 10:49:33 -05:00
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}
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2019-05-19 13:44:06 -05:00
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// Ensure all fields of `TokenTree` is `Send` and `Sync`.
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#[cfg(parallel_compiler)]
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fn _dummy()
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where
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2019-06-04 12:42:43 -05:00
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Token: Send + Sync,
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2019-05-19 13:44:06 -05:00
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DelimSpan: Send + Sync,
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DelimToken: Send + Sync,
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TokenStream: Send + Sync,
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{}
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2016-06-20 10:49:33 -05:00
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impl TokenTree {
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2019-02-08 07:53:55 -06:00
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/// Checks if this TokenTree is equal to the other, regardless of span information.
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2016-06-29 13:55:10 -05:00
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pub fn eq_unspanned(&self, other: &TokenTree) -> bool {
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match (self, other) {
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2019-06-04 12:42:43 -05:00
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(TokenTree::Token(token), TokenTree::Token(token2)) => token.kind == token2.kind,
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(TokenTree::Delimited(_, delim, tts), TokenTree::Delimited(_, delim2, tts2)) => {
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2019-01-08 23:53:14 -06:00
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delim == delim2 && tts.eq_unspanned(&tts2)
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2016-06-29 13:55:10 -05:00
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}
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2019-06-04 12:42:43 -05:00
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_ => false,
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2016-06-29 13:55:10 -05:00
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}
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}
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2019-02-17 17:06:26 -06:00
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// See comments in `Nonterminal::to_tokenstream` for why we care about
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2018-04-18 21:36:48 -05:00
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// *probably* equal here rather than actual equality
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//
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// This is otherwise the same as `eq_unspanned`, only recursing with a
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// different method.
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pub fn probably_equal_for_proc_macro(&self, other: &TokenTree) -> bool {
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match (self, other) {
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2019-06-04 12:42:43 -05:00
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(TokenTree::Token(token), TokenTree::Token(token2)) => {
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token.probably_equal_for_proc_macro(token2)
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2018-04-18 21:36:48 -05:00
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}
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2019-06-04 12:42:43 -05:00
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(TokenTree::Delimited(_, delim, tts), TokenTree::Delimited(_, delim2, tts2)) => {
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2019-01-08 23:53:14 -06:00
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delim == delim2 && tts.probably_equal_for_proc_macro(&tts2)
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2018-04-18 21:36:48 -05:00
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}
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2019-06-04 12:42:43 -05:00
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_ => false,
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2018-04-18 21:36:48 -05:00
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}
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}
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2019-02-08 07:53:55 -06:00
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/// Retrieves the TokenTree's span.
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2016-06-29 13:55:10 -05:00
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pub fn span(&self) -> Span {
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2019-06-04 12:42:43 -05:00
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match self {
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TokenTree::Token(token) => token.span,
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2018-11-29 17:02:04 -06:00
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TokenTree::Delimited(sp, ..) => sp.entire(),
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2016-06-29 13:55:10 -05:00
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}
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}
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2018-11-12 12:05:20 -06:00
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/// Modify the `TokenTree`'s span in-place.
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2017-07-19 23:54:01 -05:00
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pub fn set_span(&mut self, span: Span) {
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2019-06-04 12:42:43 -05:00
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match self {
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TokenTree::Token(token) => token.span = span,
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TokenTree::Delimited(dspan, ..) => *dspan = DelimSpan::from_single(span),
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2017-07-19 23:54:01 -05:00
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}
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}
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2017-03-17 18:41:09 -05:00
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pub fn joint(self) -> TokenStream {
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2019-01-08 22:20:56 -06:00
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TokenStream::new(vec![(self, Joint)])
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2017-03-17 18:41:09 -05:00
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}
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2018-11-29 17:02:04 -06:00
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2019-06-05 05:25:26 -05:00
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pub fn token(kind: TokenKind, span: Span) -> TokenTree {
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2019-06-05 01:39:34 -05:00
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TokenTree::Token(Token::new(kind, span))
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2019-06-04 12:42:43 -05:00
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}
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2018-11-29 17:02:04 -06:00
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/// Returns the opening delimiter as a token tree.
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2019-11-03 05:58:01 -06:00
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pub fn open_tt(span: DelimSpan, delim: DelimToken) -> TokenTree {
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TokenTree::token(token::OpenDelim(delim), span.open)
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2018-11-29 17:02:04 -06:00
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}
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/// Returns the closing delimiter as a token tree.
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2019-11-03 05:58:01 -06:00
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pub fn close_tt(span: DelimSpan, delim: DelimToken) -> TokenTree {
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TokenTree::token(token::CloseDelim(delim), span.close)
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2018-11-29 17:02:04 -06:00
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}
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2016-06-29 13:55:10 -05:00
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}
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2017-01-17 21:27:09 -06:00
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/// A `TokenStream` is an abstract sequence of tokens, organized into `TokenTree`s.
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2019-09-05 21:56:45 -05:00
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///
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2017-01-17 21:27:09 -06:00
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/// The goal is for procedural macros to work with `TokenStream`s and `TokenTree`s
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/// instead of a representation of the abstract syntax tree.
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2019-05-23 18:04:56 -05:00
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/// Today's `TokenTree`s can still contain AST via `token::Interpolated` for back-compat.
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2019-10-15 18:33:16 -05:00
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#[derive(Clone, Debug, Default, RustcEncodable, RustcDecodable)]
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2019-10-09 15:29:02 -05:00
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pub struct TokenStream(pub Lrc<Vec<TreeAndJoint>>);
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2016-07-19 17:50:34 -05:00
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2018-12-18 21:53:52 -06:00
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pub type TreeAndJoint = (TokenTree, IsJoint);
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2018-11-29 17:02:04 -06:00
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// `TokenStream` is used a lot. Make sure it doesn't unintentionally get bigger.
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#[cfg(target_arch = "x86_64")]
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2019-05-19 05:59:44 -05:00
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static_assert_size!(TokenStream, 8);
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2018-11-29 17:02:04 -06:00
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2019-10-15 18:33:16 -05:00
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#[derive(Clone, Copy, Debug, PartialEq, RustcEncodable, RustcDecodable)]
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2018-12-19 16:50:14 -06:00
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pub enum IsJoint {
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Joint,
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NonJoint
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}
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2019-02-06 11:33:01 -06:00
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use IsJoint::*;
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2018-12-19 16:50:14 -06:00
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2018-07-15 01:50:08 -05:00
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impl TokenStream {
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/// Given a `TokenStream` with a `Stream` of only two arguments, return a new `TokenStream`
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/// separating the two arguments with a comma for diagnostic suggestions.
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2019-10-16 03:59:30 -05:00
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pub fn add_comma(&self) -> Option<(TokenStream, Span)> {
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2018-08-08 00:28:09 -05:00
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// Used to suggest if a user writes `foo!(a b);`
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2019-10-09 15:29:02 -05:00
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let mut suggestion = None;
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let mut iter = self.0.iter().enumerate().peekable();
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while let Some((pos, ts)) = iter.next() {
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if let Some((_, next)) = iter.peek() {
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let sp = match (&ts, &next) {
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(_, (TokenTree::Token(Token { kind: token::Comma, .. }), _)) => continue,
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((TokenTree::Token(token_left), NonJoint),
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(TokenTree::Token(token_right), _))
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if ((token_left.is_ident() && !token_left.is_reserved_ident())
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|| token_left.is_lit()) &&
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((token_right.is_ident() && !token_right.is_reserved_ident())
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|| token_right.is_lit()) => token_left.span,
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((TokenTree::Delimited(sp, ..), NonJoint), _) => sp.entire(),
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_ => continue,
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};
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let sp = sp.shrink_to_hi();
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let comma = (TokenTree::token(token::Comma, sp), NonJoint);
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suggestion = Some((pos, comma, sp));
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2018-07-15 01:50:08 -05:00
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}
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}
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2019-10-09 15:29:02 -05:00
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if let Some((pos, comma, sp)) = suggestion {
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let mut new_stream = vec![];
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let parts = self.0.split_at(pos + 1);
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new_stream.extend_from_slice(parts.0);
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new_stream.push(comma);
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new_stream.extend_from_slice(parts.1);
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return Some((TokenStream::new(new_stream), sp));
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}
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2018-07-15 01:50:08 -05:00
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None
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}
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}
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2017-01-17 21:27:09 -06:00
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impl From<TokenTree> for TokenStream {
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2018-12-18 21:53:52 -06:00
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fn from(tree: TokenTree) -> TokenStream {
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2019-01-08 22:20:56 -06:00
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TokenStream::new(vec![(tree, NonJoint)])
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2018-12-18 21:53:52 -06:00
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}
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}
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impl From<TokenTree> for TreeAndJoint {
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fn from(tree: TokenTree) -> TreeAndJoint {
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(tree, NonJoint)
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2016-07-19 17:50:34 -05:00
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}
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}
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2019-10-13 18:37:21 -05:00
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impl iter::FromIterator<TokenTree> for TokenStream {
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fn from_iter<I: IntoIterator<Item = TokenTree>>(iter: I) -> Self {
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TokenStream::new(iter.into_iter().map(Into::into).collect::<Vec<TreeAndJoint>>())
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2018-08-12 14:45:48 -05:00
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}
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}
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2017-01-17 21:27:09 -06:00
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impl Eq for TokenStream {}
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2016-06-29 13:55:10 -05:00
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impl PartialEq<TokenStream> for TokenStream {
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fn eq(&self, other: &TokenStream) -> bool {
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2017-01-17 21:27:09 -06:00
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self.trees().eq(other.trees())
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2016-06-29 13:55:10 -05:00
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}
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}
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impl TokenStream {
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2019-10-09 15:29:02 -05:00
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pub fn new(streams: Vec<TreeAndJoint>) -> TokenStream {
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TokenStream(Lrc::new(streams))
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2017-07-19 23:54:01 -05:00
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}
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2019-10-09 15:29:02 -05:00
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pub fn is_empty(&self) -> bool {
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self.0.is_empty()
|
2016-06-29 13:55:10 -05:00
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}
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2019-10-09 15:29:02 -05:00
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pub fn len(&self) -> usize {
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self.0.len()
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2016-07-19 17:50:34 -05:00
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}
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2019-03-27 20:27:26 -05:00
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pub(crate) fn from_streams(mut streams: SmallVec<[TokenStream; 2]>) -> TokenStream {
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2017-02-18 06:45:32 -06:00
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match streams.len() {
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2019-10-09 15:29:02 -05:00
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0 => TokenStream::default(),
|
2017-03-17 18:23:12 -05:00
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1 => streams.pop().unwrap(),
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2018-12-18 21:53:52 -06:00
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_ => {
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2019-10-07 18:34:53 -05:00
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// We are going to extend the first stream in `streams` with
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// the elements from the subsequent streams. This requires
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// using `make_mut()` on the first stream, and in practice this
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// doesn't cause cloning 99.9% of the time.
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//
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// One very common use case is when `streams` has two elements,
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// where the first stream has any number of elements within
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// (often 1, but sometimes many more) and the second stream has
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// a single element within.
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// Determine how much the first stream will be extended.
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// Needed to avoid quadratic blow up from on-the-fly
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// reallocations (#57735).
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let num_appends = streams.iter()
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.skip(1)
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.map(|ts| ts.len())
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2019-01-30 08:12:41 -06:00
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.sum();
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2019-10-07 18:34:53 -05:00
|
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// Get the first stream. If it's `None`, create an empty
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// stream.
|
2019-11-04 08:59:09 -06:00
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let mut iter = streams.drain(..);
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2019-10-09 15:29:02 -05:00
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let mut first_stream_lrc = iter.next().unwrap().0;
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2019-10-07 18:34:53 -05:00
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// Append the elements to the first stream, after reserving
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// space for them.
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let first_vec_mut = Lrc::make_mut(&mut first_stream_lrc);
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first_vec_mut.reserve(num_appends);
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|
|
for stream in iter {
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2019-10-09 15:29:02 -05:00
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first_vec_mut.extend(stream.0.iter().cloned());
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2018-12-18 21:53:52 -06:00
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}
|
2019-10-07 18:34:53 -05:00
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// Create the final `TokenStream`.
|
2019-10-09 15:29:02 -05:00
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|
|
TokenStream(first_stream_lrc)
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2018-12-18 21:53:52 -06:00
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}
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}
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}
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|
2017-02-18 00:18:29 -06:00
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pub fn trees(&self) -> Cursor {
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|
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self.clone().into_trees()
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|
}
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pub fn into_trees(self) -> Cursor {
|
2017-01-17 21:27:09 -06:00
|
|
|
Cursor::new(self)
|
2016-06-29 13:55:10 -05:00
|
|
|
}
|
|
|
|
|
2019-09-05 21:56:45 -05:00
|
|
|
/// Compares two `TokenStream`s, checking equality without regarding span information.
|
2016-07-19 17:50:34 -05:00
|
|
|
pub fn eq_unspanned(&self, other: &TokenStream) -> bool {
|
2018-04-10 14:52:47 -05:00
|
|
|
let mut t1 = self.trees();
|
|
|
|
let mut t2 = other.trees();
|
|
|
|
for (t1, t2) in t1.by_ref().zip(t2.by_ref()) {
|
2017-02-18 00:18:29 -06:00
|
|
|
if !t1.eq_unspanned(&t2) {
|
2016-07-19 17:50:34 -05:00
|
|
|
return false;
|
2016-06-29 13:55:10 -05:00
|
|
|
}
|
|
|
|
}
|
2018-04-10 14:52:47 -05:00
|
|
|
t1.next().is_none() && t2.next().is_none()
|
2016-06-29 13:55:10 -05:00
|
|
|
}
|
2017-03-17 18:41:09 -05:00
|
|
|
|
2019-02-17 17:06:26 -06:00
|
|
|
// See comments in `Nonterminal::to_tokenstream` for why we care about
|
2018-04-18 21:36:48 -05:00
|
|
|
// *probably* equal here rather than actual equality
|
|
|
|
//
|
|
|
|
// This is otherwise the same as `eq_unspanned`, only recursing with a
|
|
|
|
// different method.
|
|
|
|
pub fn probably_equal_for_proc_macro(&self, other: &TokenStream) -> bool {
|
2018-11-17 01:37:23 -06:00
|
|
|
// When checking for `probably_eq`, we ignore certain tokens that aren't
|
|
|
|
// preserved in the AST. Because they are not preserved, the pretty
|
|
|
|
// printer arbitrarily adds or removes them when printing as token
|
|
|
|
// streams, making a comparison between a token stream generated from an
|
|
|
|
// AST and a token stream which was parsed into an AST more reliable.
|
|
|
|
fn semantic_tree(tree: &TokenTree) -> bool {
|
2019-06-04 12:42:43 -05:00
|
|
|
if let TokenTree::Token(token) = tree {
|
|
|
|
if let
|
|
|
|
// The pretty printer tends to add trailing commas to
|
|
|
|
// everything, and in particular, after struct fields.
|
|
|
|
| token::Comma
|
|
|
|
// The pretty printer emits `NoDelim` as whitespace.
|
|
|
|
| token::OpenDelim(DelimToken::NoDelim)
|
|
|
|
| token::CloseDelim(DelimToken::NoDelim)
|
|
|
|
// The pretty printer collapses many semicolons into one.
|
|
|
|
| token::Semi
|
|
|
|
// The pretty printer collapses whitespace arbitrarily and can
|
|
|
|
// introduce whitespace from `NoDelim`.
|
|
|
|
| token::Whitespace
|
|
|
|
// The pretty printer can turn `$crate` into `::crate_name`
|
|
|
|
| token::ModSep = token.kind {
|
|
|
|
return false;
|
|
|
|
}
|
2018-11-17 01:37:23 -06:00
|
|
|
}
|
2019-06-04 12:42:43 -05:00
|
|
|
true
|
2018-11-17 01:37:23 -06:00
|
|
|
}
|
|
|
|
|
|
|
|
let mut t1 = self.trees().filter(semantic_tree);
|
|
|
|
let mut t2 = other.trees().filter(semantic_tree);
|
2018-04-18 21:36:48 -05:00
|
|
|
for (t1, t2) in t1.by_ref().zip(t2.by_ref()) {
|
|
|
|
if !t1.probably_equal_for_proc_macro(&t2) {
|
|
|
|
return false;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
t1.next().is_none() && t2.next().is_none()
|
|
|
|
}
|
|
|
|
|
2017-07-21 18:44:23 -05:00
|
|
|
pub fn map_enumerated<F: FnMut(usize, TokenTree) -> TokenTree>(self, mut f: F) -> TokenStream {
|
2019-10-09 15:29:02 -05:00
|
|
|
TokenStream(Lrc::new(
|
|
|
|
self.0
|
|
|
|
.iter()
|
|
|
|
.enumerate()
|
|
|
|
.map(|(i, (tree, is_joint))| (f(i, tree.clone()), *is_joint))
|
|
|
|
.collect()
|
|
|
|
))
|
2017-07-19 23:54:01 -05:00
|
|
|
}
|
|
|
|
|
2017-03-17 18:41:09 -05:00
|
|
|
pub fn map<F: FnMut(TokenTree) -> TokenTree>(self, mut f: F) -> TokenStream {
|
2019-10-09 15:29:02 -05:00
|
|
|
TokenStream(Lrc::new(
|
|
|
|
self.0
|
|
|
|
.iter()
|
|
|
|
.map(|(tree, is_joint)| (f(tree.clone()), *is_joint))
|
|
|
|
.collect()
|
|
|
|
))
|
2017-03-17 18:41:09 -05:00
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2019-03-27 20:27:26 -05:00
|
|
|
// 99.5%+ of the time we have 1 or 2 elements in this vector.
|
2018-07-22 10:48:29 -05:00
|
|
|
#[derive(Clone)]
|
2019-03-27 20:27:26 -05:00
|
|
|
pub struct TokenStreamBuilder(SmallVec<[TokenStream; 2]>);
|
2017-03-17 18:41:09 -05:00
|
|
|
|
|
|
|
impl TokenStreamBuilder {
|
2017-06-04 20:41:33 -05:00
|
|
|
pub fn new() -> TokenStreamBuilder {
|
2019-03-27 20:27:26 -05:00
|
|
|
TokenStreamBuilder(SmallVec::new())
|
2017-06-04 20:41:33 -05:00
|
|
|
}
|
|
|
|
|
2017-03-17 18:41:09 -05:00
|
|
|
pub fn push<T: Into<TokenStream>>(&mut self, stream: T) {
|
2019-10-07 21:32:59 -05:00
|
|
|
let mut stream = stream.into();
|
|
|
|
|
|
|
|
// If `self` is not empty and the last tree within the last stream is a
|
|
|
|
// token tree marked with `Joint`...
|
2019-10-09 15:29:02 -05:00
|
|
|
if let Some(TokenStream(ref mut last_stream_lrc)) = self.0.last_mut() {
|
2019-10-07 21:32:59 -05:00
|
|
|
if let Some((TokenTree::Token(last_token), Joint)) = last_stream_lrc.last() {
|
|
|
|
|
|
|
|
// ...and `stream` is not empty and the first tree within it is
|
|
|
|
// a token tree...
|
2019-10-09 15:29:02 -05:00
|
|
|
let TokenStream(ref mut stream_lrc) = stream;
|
|
|
|
if let Some((TokenTree::Token(token), is_joint)) = stream_lrc.first() {
|
|
|
|
|
|
|
|
// ...and the two tokens can be glued together...
|
|
|
|
if let Some(glued_tok) = last_token.glue(&token) {
|
|
|
|
|
|
|
|
// ...then do so, by overwriting the last token
|
|
|
|
// tree in `self` and removing the first token tree
|
|
|
|
// from `stream`. This requires using `make_mut()`
|
|
|
|
// on the last stream in `self` and on `stream`,
|
|
|
|
// and in practice this doesn't cause cloning 99.9%
|
|
|
|
// of the time.
|
|
|
|
|
|
|
|
// Overwrite the last token tree with the merged
|
|
|
|
// token.
|
|
|
|
let last_vec_mut = Lrc::make_mut(last_stream_lrc);
|
|
|
|
*last_vec_mut.last_mut().unwrap() =
|
|
|
|
(TokenTree::Token(glued_tok), *is_joint);
|
|
|
|
|
|
|
|
// Remove the first token tree from `stream`. (This
|
|
|
|
// is almost always the only tree in `stream`.)
|
|
|
|
let stream_vec_mut = Lrc::make_mut(stream_lrc);
|
|
|
|
stream_vec_mut.remove(0);
|
|
|
|
|
|
|
|
// Don't push `stream` if it's empty -- that could
|
|
|
|
// block subsequent token gluing, by getting
|
|
|
|
// between two token trees that should be glued
|
|
|
|
// together.
|
|
|
|
if !stream.is_empty() {
|
|
|
|
self.0.push(stream);
|
2019-10-07 21:32:59 -05:00
|
|
|
}
|
2019-10-09 15:29:02 -05:00
|
|
|
return;
|
2019-10-07 21:32:59 -05:00
|
|
|
}
|
2017-03-17 18:41:09 -05:00
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
self.0.push(stream);
|
|
|
|
}
|
|
|
|
|
|
|
|
pub fn build(self) -> TokenStream {
|
2018-12-18 21:53:52 -06:00
|
|
|
TokenStream::from_streams(self.0)
|
2017-03-17 18:41:09 -05:00
|
|
|
}
|
2016-06-29 13:55:10 -05:00
|
|
|
}
|
|
|
|
|
2017-06-09 22:30:33 -05:00
|
|
|
#[derive(Clone)]
|
2018-12-18 21:53:52 -06:00
|
|
|
pub struct Cursor {
|
|
|
|
pub stream: TokenStream,
|
2017-02-18 06:45:32 -06:00
|
|
|
index: usize,
|
2017-01-17 21:27:09 -06:00
|
|
|
}
|
2016-06-29 13:55:10 -05:00
|
|
|
|
2017-03-17 18:23:12 -05:00
|
|
|
impl Iterator for Cursor {
|
|
|
|
type Item = TokenTree;
|
|
|
|
|
|
|
|
fn next(&mut self) -> Option<TokenTree> {
|
2018-12-18 21:53:52 -06:00
|
|
|
self.next_with_joint().map(|(tree, _)| tree)
|
2017-03-17 18:23:12 -05:00
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2017-02-18 00:18:29 -06:00
|
|
|
impl Cursor {
|
|
|
|
fn new(stream: TokenStream) -> Self {
|
2018-12-18 21:53:52 -06:00
|
|
|
Cursor { stream, index: 0 }
|
2017-03-17 18:41:09 -05:00
|
|
|
}
|
|
|
|
|
2018-12-18 21:53:52 -06:00
|
|
|
pub fn next_with_joint(&mut self) -> Option<TreeAndJoint> {
|
2019-10-09 15:29:02 -05:00
|
|
|
if self.index < self.stream.len() {
|
|
|
|
self.index += 1;
|
|
|
|
Some(self.stream.0[self.index - 1].clone())
|
|
|
|
} else {
|
|
|
|
None
|
2017-03-28 20:55:01 -05:00
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2018-12-18 21:53:52 -06:00
|
|
|
pub fn append(&mut self, new_stream: TokenStream) {
|
|
|
|
if new_stream.is_empty() {
|
|
|
|
return;
|
2017-02-19 23:44:06 -06:00
|
|
|
}
|
2018-12-18 21:53:52 -06:00
|
|
|
let index = self.index;
|
2019-10-09 15:29:02 -05:00
|
|
|
let stream = mem::take(&mut self.stream);
|
2019-03-27 20:27:26 -05:00
|
|
|
*self = TokenStream::from_streams(smallvec![stream, new_stream]).into_trees();
|
2018-12-18 21:53:52 -06:00
|
|
|
self.index = index;
|
2017-02-19 23:44:06 -06:00
|
|
|
}
|
|
|
|
|
|
|
|
pub fn look_ahead(&self, n: usize) -> Option<TokenTree> {
|
2019-10-09 15:29:02 -05:00
|
|
|
self.stream.0[self.index ..].get(n).map(|(tree, _)| tree.clone())
|
2017-02-19 23:44:06 -06:00
|
|
|
}
|
2016-06-29 13:55:10 -05:00
|
|
|
}
|
|
|
|
|
2018-09-08 20:07:02 -05:00
|
|
|
#[derive(Debug, Copy, Clone, PartialEq, RustcEncodable, RustcDecodable)]
|
|
|
|
pub struct DelimSpan {
|
|
|
|
pub open: Span,
|
|
|
|
pub close: Span,
|
|
|
|
}
|
|
|
|
|
|
|
|
impl DelimSpan {
|
|
|
|
pub fn from_single(sp: Span) -> Self {
|
|
|
|
DelimSpan {
|
|
|
|
open: sp,
|
|
|
|
close: sp,
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
pub fn from_pair(open: Span, close: Span) -> Self {
|
|
|
|
DelimSpan { open, close }
|
|
|
|
}
|
|
|
|
|
|
|
|
pub fn dummy() -> Self {
|
|
|
|
Self::from_single(DUMMY_SP)
|
|
|
|
}
|
|
|
|
|
|
|
|
pub fn entire(self) -> Span {
|
|
|
|
self.open.with_hi(self.close.hi())
|
|
|
|
}
|
|
|
|
}
|