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rustc: Enable writing "unsafe extern fn() {}"

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Previously, the parser would not allow you to simultaneously implement a
function with a different abi as well as being unsafe at the same time. This
extends the parser to allow functions of the form:

    unsafe extern fn foo() {
        // ...
    }

The closure type grammar was also changed to reflect this reversal, types
previously written as "extern unsafe fn()" must now be written as
"unsafe extern fn()". The parser currently has a hack which allows the old
style, but this will go away once a snapshot has landed.

Closes #10025

[breaking-change]
This commit is contained in:
Alex Crichton
2014-05-06 18:43:56 -07:00
parent cf6857b9e9
commit 08237cad8d
15 changed files with 59 additions and 49 deletions
Download Patch File Download Diff File Expand all files Collapse all files

38
src/libsyntax/parse/parser.rs
View File

@@ -27,7 +27,7 @@ use ast::{ExprLit, ExprLoop, ExprMac};
use ast::{ExprMethodCall, ExprParen, ExprPath, ExprProc};
use ast::{ExprRepeat, ExprRet, ExprStruct, ExprTup, ExprUnary};
use ast::{ExprVec, ExprVstore, ExprVstoreSlice};
use ast::{ExprVstoreMutSlice, ExprWhile, ExprForLoop, ExternFn, Field, FnDecl};
use ast::{ExprVstoreMutSlice, ExprWhile, ExprForLoop, Field, FnDecl};
use ast::{ExprVstoreUniq, Once, Many};
use ast::{ForeignItem, ForeignItemStatic, ForeignItemFn, ForeignMod};
use ast::{Ident, NormalFn, Inherited, Item, Item_, ItemStatic};
@@ -881,25 +881,29 @@ impl<'a> Parser<'a> {
pub fn parse_ty_bare_fn(&mut self) -> Ty_ {
/*
[extern "ABI"] [unsafe] fn <'lt> (S) -> T
^~~~^ ^~~~~~~^ ^~~~^ ^~^ ^
| | | | |
| | | | Return type
| | | Argument types
| | Lifetimes
| |
| Function Style
ABI
[unsafe] [extern "ABI"] fn <'lt> (S) -> T
^~~~^ ^~~~^ ^~~~^ ^~^ ^
| | | | |
| | | | Return type
| | | Argument types
| | Lifetimes
| ABI
Function Style
*/
let fn_style = self.parse_unsafety();
let abi = if self.eat_keyword(keywords::Extern) {
self.parse_opt_abi().unwrap_or(abi::C)
} else {
abi::Rust
};
let fn_style = self.parse_unsafety();
// NOTE: remove after a stage0 snapshot
let fn_style = match self.parse_unsafety() {
UnsafeFn => UnsafeFn,
NormalFn => fn_style,
};
self.expect_keyword(keywords::Fn);
let (decl, lifetimes) = self.parse_ty_fn_decl(true);
return TyBareFn(@BareFnTy {
@@ -1245,6 +1249,7 @@ impl<'a> Parser<'a> {
self.expect_and();
self.parse_borrowed_pointee()
} else if self.is_keyword(keywords::Extern) ||
self.is_keyword(keywords::Unsafe) ||
self.token_is_bare_fn_keyword() {
// BARE FUNCTION
self.parse_ty_bare_fn()
@@ -4551,7 +4556,7 @@ impl<'a> Parser<'a> {
// EXTERN FUNCTION ITEM
let abi = opt_abi.unwrap_or(abi::C);
let (ident, item_, extra_attrs) =
self.parse_item_fn(ExternFn, abi);
self.parse_item_fn(NormalFn, abi);
let item = self.mk_item(lo,
self.last_span.hi,
ident,
@@ -4605,9 +4610,14 @@ impl<'a> Parser<'a> {
&& self.look_ahead(1u, |t| *t != token::LBRACE) {
// UNSAFE FUNCTION ITEM
self.bump();
let abi = if self.eat_keyword(keywords::Extern) {
self.parse_opt_abi().unwrap_or(abi::C)
} else {
abi::Rust
};
self.expect_keyword(keywords::Fn);
let (ident, item_, extra_attrs) =
self.parse_item_fn(UnsafeFn, abi::Rust);
self.parse_item_fn(UnsafeFn, abi);
let item = self.mk_item(lo,
self.last_span.hi,
ident,