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Add Span and separate open/close delims to TTDelim

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This came up when working [on the gl-rs generator extension](990383de80/src/gl_generator/lib.rs (L135-L146)).

The new definition of  `TTDelim` adds an associated `Span` that covers the whole token tree and enforces the invariant that a delimited sequence of token trees must have an opening and closing delimiter.

A `get_span` method has also been added to `TokenTree` type to make it easier to implement better error messages for syntax extensions.
This commit is contained in:
Brendan Zabarauskas
2014-10-22 16:37:20 +11:00
parent 80e5fe1a56
commit 971d776aa5
9 changed files with 135 additions and 88 deletions
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8
src/libsyntax/print/pprust.rs
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@@ -1020,7 +1020,13 @@ impl<'a> State<'a> {
/// expression arguments as expressions). It can be done! I think.
pub fn print_tt(&mut self, tt: &ast::TokenTree) -> IoResult<()> {
match *tt {
ast::TTDelim(ref tts) => self.print_tts(tts.as_slice()),
ast::TTDelim(_, ref open, ref tts, ref close) => {
try!(word(&mut self.s, parse::token::to_string(&open.token).as_slice()));
try!(space(&mut self.s));
try!(self.print_tts(tts.as_slice()));
try!(space(&mut self.s));
word(&mut self.s, parse::token::to_string(&close.token).as_slice())
},
ast::TTTok(_, ref tk) => {
try!(word(&mut self.s, parse::token::to_string(tk).as_slice()));
match *tk {