Merge pull request #10 from robinst/allow-opening-curly-as-literal

Allow unescaped `{` as literal when not after atom

Author: raphlinus

src/parse.rs

@@ -200,7 +200,7 @@ impl<'a> Parser<'a> {
             )),
             b'(' => self.parse_group(ix, depth),
             b'\\' => self.parse_escape(ix),
-            b'+' | b'*' | b'?' | b'|' | b')' | b'{' =>
+            b'+' | b'*' | b'?' | b'|' | b')' =>
                 Ok((ix, Expr::Empty)),
             b'[' => self.parse_class(ix),
             b'#' | b' ' | b'\r' | b'\n' | b'\t'
@@ -558,6 +558,20 @@ mod tests {
         assert_eq!(p("]"), make_literal("]"));
     }
 
+    #[test]
+    fn literal_unescaped_opening_curly() {
+        assert_eq!(p("{"), make_literal("{"));
+        assert_eq!(p("({)"), Expr::Group(Box::new(
+            make_literal("{"),
+        )));
+        assert_eq!(p("a|{"), Expr::Alt(vec![
+            make_literal("a"),
+            make_literal("{"),
+        ]));
+        assert_eq!(p("{{2}"), Expr::Repeat{ child: Box::new(make_literal("{")),
+            lo: 2, hi: 2, greedy: true });
+    }
+
     #[test]
     fn literal_escape() {
         assert_eq!(p("\\'"), make_literal("'"));
@@ -611,6 +625,13 @@ mod tests {
         )));
     }
 
+    #[test]
+    fn group_repeat() {
+        assert_eq!(p("(a){2}"), Expr::Repeat{
+            child: Box::new(Expr::Group(Box::new(make_literal("a")))), lo: 2, hi: 2, greedy: true
+        });
+    }
+
     #[test]
     fn repeat() {
         assert_eq!(p("a{2,42}"), Expr::Repeat{ child: Box::new(make_literal("a")),