auto merge of #13700 : BurntSushi/rust/regexp, r=alexcrichton

Implements [RFC 7](https://github.com/rust-lang/rfcs/blob/master/active/0007-regexps.md) and will hopefully resolve #3591. The crate is marked as experimental. It includes a syntax extension for compiling regexps to native Rust code.

Embeds and passes the `basic`, `nullsubexpr` and `repetition` tests from [Glenn Fowler's (slightly modified by Russ Cox for leftmost-first semantics) testregex test suite](http://www2.research.att.com/~astopen/testregex/testregex.html). I've also hand written a plethora of other tests that exercise Unicode support, the parser, public API, etc. Also includes a `regex-dna` benchmark for the shootout.

I know the addition looks huge at first, but consider these things:

1. More than half the number of lines is dedicated to Unicode character classes.
2. Of the ~4,500 lines remaining, 1,225 of them are comments.
3. Another ~800 are tests.
4. That leaves 2500 lines for the meat. The parser is ~850 of them. The public API, compiler, dynamic VM and code generator (for `regexp!`) make up the rest.

1 files changed, 28 insertions, 0 deletions

diff --git a/src/test/compile-fail/syntax-extension-regex-invalid.rs b/src/test/compile-fail/syntax-extension-regex-invalid.rs
new file mode 100644
index 00000000000..0e072dc1c06
--- /dev/null
+++ b/src/test/compile-fail/syntax-extension-regex-invalid.rs
@@ -0,0 +1,28 @@
+// Copyright 2014 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.
+
+// FIXME(#13725) windows needs fixing.
+// ignore-win32
+// ignore-stage1
+
+#![feature(phase)]
+
+extern crate regex;
+#[phase(syntax)] extern crate regex_macros;
+
+// Tests to make sure that `regex!` will produce a compile error when given
+// an invalid regular expression.
+// More exhaustive failure tests for the parser are done with the traditional
+// unit testing infrastructure, since both dynamic and native regexes use the
+// same parser.
+
+fn main() {
+    let _ = regex!("("); //~ ERROR Regex syntax error
+}