need choice for 6-tuple

src/choice.rs

@@ -144,6 +144,48 @@ where
     }
 }
 
+impl<I, O, E, P1, P2, P3, P4, P5, P6> Choice<I, O, E> for (P1, P2, P3, P4, P5, P6)
+where
+    P1: Parser<I, O, E>,
+    P2: Parser<I, O, E>,
+    P3: Parser<I, O, E>,
+    P4: Parser<I, O, E>,
+    P5: Parser<I, O, E>,
+    P6: Parser<I, O, E>,
+    I: Clone,
+{
+    fn parse(&self, input: I) -> ParseResult<I, O, E> {
+        let parser1 = &self.0;
+        let parser2 = &self.1;
+        let parser3 = &self.2;
+        let parser4 = &self.3;
+        let parser5 = &self.4;
+        let parser6 = &self.5;
+
+        //TODO need a more principled way to return an error when no choices work
+        let mut err = None;
+
+        for parser in [
+            parser1 as &dyn Parser<I, O, E>,
+            parser2,
+            parser3,
+            parser4,
+            parser5,
+            parser6,
+        ]
+        .iter()
+        {
+            match parser.parse(input.clone()) {
+                Ok(result) => return Ok(result),
+                Err(e) => {
+                    err = Some(e);
+                }
+            }
+        }
+        Err(err.unwrap())
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;