| use crate::print::pprust::token_to_string; |
| use crate::parse::lexer::{StringReader, UnmatchedBrace}; |
| use crate::parse::{token, PResult}; |
| use crate::tokenstream::{DelimSpan, IsJoint::*, TokenStream, TokenTree, TreeAndJoint}; |
| |
| impl<'a> StringReader<'a> { |
| // Parse a stream of tokens into a list of `TokenTree`s, up to an `Eof`. |
| crate fn parse_all_token_trees(&mut self) -> PResult<'a, TokenStream> { |
| let mut tts = Vec::new(); |
| |
| while self.token != token::Eof { |
| tts.push(self.parse_token_tree()?); |
| } |
| |
| Ok(TokenStream::new(tts)) |
| } |
| |
| // Parse a stream of tokens into a list of `TokenTree`s, up to a `CloseDelim`. |
| fn parse_token_trees_until_close_delim(&mut self) -> TokenStream { |
| let mut tts = vec![]; |
| loop { |
| if let token::CloseDelim(..) = self.token { |
| return TokenStream::new(tts); |
| } |
| |
| match self.parse_token_tree() { |
| Ok(tree) => tts.push(tree), |
| Err(mut e) => { |
| e.emit(); |
| return TokenStream::new(tts); |
| } |
| } |
| } |
| } |
| |
| fn parse_token_tree(&mut self) -> PResult<'a, TreeAndJoint> { |
| let sm = self.sess.source_map(); |
| match self.token { |
| token::Eof => { |
| let msg = "this file contains an un-closed delimiter"; |
| let mut err = self.sess.span_diagnostic.struct_span_err(self.span, msg); |
| for &(_, sp) in &self.open_braces { |
| err.span_label(sp, "un-closed delimiter"); |
| } |
| |
| if let Some((delim, _)) = self.open_braces.last() { |
| if let Some((_, open_sp, close_sp)) = self.matching_delim_spans.iter() |
| .filter(|(d, open_sp, close_sp)| { |
| |
| if let Some(close_padding) = sm.span_to_margin(*close_sp) { |
| if let Some(open_padding) = sm.span_to_margin(*open_sp) { |
| return delim == d && close_padding != open_padding; |
| } |
| } |
| false |
| }).next() // these are in reverse order as they get inserted on close, but |
| { // we want the last open/first close |
| err.span_label( |
| *open_sp, |
| "this delimiter might not be properly closed...", |
| ); |
| err.span_label( |
| *close_sp, |
| "...as it matches this but it has different indentation", |
| ); |
| } |
| } |
| Err(err) |
| }, |
| token::OpenDelim(delim) => { |
| // The span for beginning of the delimited section |
| let pre_span = self.span; |
| |
| // Parse the open delimiter. |
| self.open_braces.push((delim, self.span)); |
| self.real_token(); |
| |
| // Parse the token trees within the delimiters. |
| // We stop at any delimiter so we can try to recover if the user |
| // uses an incorrect delimiter. |
| let tts = self.parse_token_trees_until_close_delim(); |
| |
| // Expand to cover the entire delimited token tree |
| let delim_span = DelimSpan::from_pair(pre_span, self.span); |
| |
| match self.token { |
| // Correct delimiter. |
| token::CloseDelim(d) if d == delim => { |
| let (open_brace, open_brace_span) = self.open_braces.pop().unwrap(); |
| if self.open_braces.len() == 0 { |
| // Clear up these spans to avoid suggesting them as we've found |
| // properly matched delimiters so far for an entire block. |
| self.matching_delim_spans.clear(); |
| } else { |
| self.matching_delim_spans.push( |
| (open_brace, open_brace_span, self.span), |
| ); |
| } |
| // Parse the close delimiter. |
| self.real_token(); |
| } |
| // Incorrect delimiter. |
| token::CloseDelim(other) => { |
| let mut unclosed_delimiter = None; |
| let mut candidate = None; |
| if self.last_unclosed_found_span != Some(self.span) { |
| // do not complain about the same unclosed delimiter multiple times |
| self.last_unclosed_found_span = Some(self.span); |
| // This is a conservative error: only report the last unclosed |
| // delimiter. The previous unclosed delimiters could actually be |
| // closed! The parser just hasn't gotten to them yet. |
| if let Some(&(_, sp)) = self.open_braces.last() { |
| unclosed_delimiter = Some(sp); |
| }; |
| if let Some(current_padding) = sm.span_to_margin(self.span) { |
| for (brace, brace_span) in &self.open_braces { |
| if let Some(padding) = sm.span_to_margin(*brace_span) { |
| // high likelihood of these two corresponding |
| if current_padding == padding && brace == &other { |
| candidate = Some(*brace_span); |
| } |
| } |
| } |
| } |
| let (tok, _) = self.open_braces.pop().unwrap(); |
| self.unmatched_braces.push(UnmatchedBrace { |
| expected_delim: tok, |
| found_delim: other, |
| found_span: self.span, |
| unclosed_span: unclosed_delimiter, |
| candidate_span: candidate, |
| }); |
| } else { |
| self.open_braces.pop(); |
| } |
| |
| // If the incorrect delimiter matches an earlier opening |
| // delimiter, then don't consume it (it can be used to |
| // close the earlier one). Otherwise, consume it. |
| // E.g., we try to recover from: |
| // fn foo() { |
| // bar(baz( |
| // } // Incorrect delimiter but matches the earlier `{` |
| if !self.open_braces.iter().any(|&(b, _)| b == other) { |
| self.real_token(); |
| } |
| } |
| token::Eof => { |
| // Silently recover, the EOF token will be seen again |
| // and an error emitted then. Thus we don't pop from |
| // self.open_braces here. |
| }, |
| _ => {} |
| } |
| |
| Ok(TokenTree::Delimited( |
| delim_span, |
| delim, |
| tts.into() |
| ).into()) |
| }, |
| token::CloseDelim(_) => { |
| // An unexpected closing delimiter (i.e., there is no |
| // matching opening delimiter). |
| let token_str = token_to_string(&self.token); |
| let msg = format!("unexpected close delimiter: `{}`", token_str); |
| let mut err = self.sess.span_diagnostic.struct_span_err(self.span, &msg); |
| err.span_label(self.span, "unexpected close delimiter"); |
| Err(err) |
| }, |
| _ => { |
| let tt = TokenTree::Token(self.span, self.token.clone()); |
| // Note that testing for joint-ness here is done via the raw |
| // source span as the joint-ness is a property of the raw source |
| // rather than wanting to take `override_span` into account. |
| let raw = self.span_src_raw; |
| self.real_token(); |
| let is_joint = raw.hi() == self.span_src_raw.lo() && token::is_op(&self.token); |
| Ok((tt, if is_joint { Joint } else { NonJoint })) |
| } |
| } |
| } |
| } |
