impl Not combinator

1 files changed, 30 insertions, 0 deletions

diff --git a/src/lib.rs b/src/lib.rs
index fc91cb1..e0be671 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -740,6 +740,36 @@ where
     }
 }
 
+struct Not<P> {
+    parser: P,
+}
+
+impl<I, P> Parser<I> for Not<P>
+where
+    I: Input,
+    P: Parser<I>,
+{
+    type Output = ();
+
+    fn run<OM: Mode, EM: Mode, T: Trace<I>>(
+        &mut self,
+        it: InputIter<I>,
+    ) -> ParserResult<I, Self::Output, OM, EM> {
+        match self.parser.check(it.clone()) {
+            Ok(_) => Ok((it, OM::bind(|| ()))),
+            Err(rest) => Err(EM::bind(|| rest)),
+        }
+    }
+}
+
+pub fn not<I, P>(parser: P) -> impl Parser<I, Output = ()>
+where
+    I: Input,
+    P: Parser<I>,
+{
+    Not { parser }
+}
+
 pub fn alpha<I>() -> impl Parser<I, Output = I>
 where
     I: Input,