// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
use print::pprust::token_to_string;
use parse::lexer::StringReader;
use parse::{token, PResult};
use tokenstream::{Delimited, DelimSpan, TokenStream, TokenTree};
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::concat(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::concat(tts);
}
match self.parse_token_tree() {
Ok(tree) => tts.push(tree),
Err(mut e) => {
e.emit();
return TokenStream::concat(tts);
}
}
}
}
fn parse_token_tree(&mut self) -> PResult<'a, TokenStream> {
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();
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 token_str = token_to_string(&self.token);
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);
let msg = format!("incorrect close delimiter: `{}`", token_str);
let mut err = self.sess.span_diagnostic.struct_span_err(
self.span,
&msg,
);
err.span_label(self.span, "incorrect close delimiter");
// 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() {
err.span_label(sp, "un-closed delimiter");
};
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 {
err.span_label(
*brace_span,
"close delimiter possibly meant for this",
);
}
}
}
}
err.emit();
}
self.open_braces.pop().unwrap();
// 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, Delimited {
delim,
tts: 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(if is_joint { tt.joint() } else { tt.into() })
}
}
}
}