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Auto merge of #23857 - phildawes:libsyntax_nopanic, r=nikomatsakis

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Hello! 

I've been working towards a libsyntax without panics. See:
http://internals.rust-lang.org/t/changing-libsyntax-to-use-result-instead-of-panic/1670

This patch changes the internals of parser.rs to use Result<> rather than panicing. It keeps the following old-style panicing functions as a facade:
parse_expr, parse_item, parse_pat, parse_arm, parse_ty, parse_stmt

I left these functions because I wasn't sure what to do about the quote_* macros or how many syntax-extensions would break if these and quoting macros returned Result.

The gyst of the rest of the patch is:

 - Functions in parse/parser.rs return PResult<> rather than panicing
 - Other functions in libsyntax call panic! explicitly if they rely on panicing behaviour.
 - I added a macro 'panictry!()' to act as scaffolding for callers while converting panicing functions. (This does the same as 'unwrap()' but is easier to grep for and turn into try!()).

Am I on the right track?  I'd quite like to get something merged soon as keeping this rebased in the face of libsyntax changes is a lot of work. Please let me know what changes you'd like to see to make this happen.

Thanks!, Phil
This commit is contained in:
bors 2015-04-06 22:08:01 +00:00
commit b49a5ef003
23 changed files with 1397 additions and 1318 deletions
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5
src/librustc/metadata/creader.rs
View file

@ -528,7 +528,10 @@ impl<'a> CrateReader<'a> {
source_name.clone(),
body);
let lo = p.span.lo;
let body = p.parse_all_token_trees();
let body = match p.parse_all_token_trees() {
Ok(body) => body,
Err(err) => panic!(err),
};
let span = mk_sp(lo, p.last_span.hi);
p.abort_if_errors();
macros.push(ast::MacroDef {

4
src/librustc/session/mod.rs
View file

@ -68,13 +68,13 @@ impl Session {
if self.opts.treat_err_as_bug {
self.span_bug(sp, msg);
}
self.diagnostic().span_fatal(sp, msg)
panic!(self.diagnostic().span_fatal(sp, msg))
}
pub fn span_fatal_with_code(&self, sp: Span, msg: &str, code: &str) -> ! {
if self.opts.treat_err_as_bug {
self.span_bug(sp, msg);
}
self.diagnostic().span_fatal_with_code(sp, msg, code)
panic!(self.diagnostic().span_fatal_with_code(sp, msg, code))
}
pub fn fatal(&self, msg: &str) -> ! {
if self.opts.treat_err_as_bug {