19343860aa
Statement macros are now treated somewhat like item macros, in that a
statement macro can now expand into a series of statements, rather than
just a single statement.
This allows statement macros to be nested inside other kinds of macros and
expand properly, where previously the expansion would only work when no
nesting was present.
See: src/test/run-pass/macro-stmt_macro_in_expr_macro.rs
src/test/run-pass/macro-nested_stmt_macro.rs
This changes the interface of the MacResult trait. make_stmt has become
make_stmts and now returns a vector, rather than a single item. Plugin
writers who were implementing MacResult will have breakage, as well as
anyone using MacEager::stmt.
See: src/libsyntax/ext/base.rs
This also causes a minor difference in behavior to the diagnostics
produced by certain malformed macros.
See: src/test/compile-fail/macro-incomplete-parse.rs
30 lines
699 B
Rust
30 lines
699 B
Rust
// Copyright 2015 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.
|
|
|
|
macro_rules! foo {
|
|
() => {
|
|
struct Bar;
|
|
struct Baz;
|
|
}
|
|
}
|
|
|
|
macro_rules! grault {
|
|
() => {{
|
|
foo!();
|
|
struct Xyzzy;
|
|
0
|
|
}}
|
|
}
|
|
|
|
fn main() {
|
|
let x = grault!();
|
|
assert_eq!(x, 0);
|
|
}
|