wip: better error

Author: djc

askama_parser/src/expr.rs

@@ -200,10 +200,22 @@ impl<'a> Expr<'a> {
             Ok((i, (fname, args)))
         }
 
-        let (i, (obj, filters)) = tuple((
+        let result = tuple((
             |i| Self::prefix(i, level),
             many_m_n(0, 16, |i| filter(i, level)),
-        ))(i)?;
+        ))(i);
+
+        let (i, (obj, filters)) = match result {
+            Ok((i, (obj, filters))) => (i, (obj, filters)),
+            Err(nom::Err::Error(err)) if dbg!(err.kind) == ErrorKind::ManyMN => {
+                return Err(nom::Err::Failure(ErrorContext {
+                    input: i,
+                    message: Some(Cow::Borrowed("too many nested filters")),
+                    kind: ErrorKind::ManyMN,
+                }))
+            }
+            Err(e) => return Err(e),
+        };
 
         let mut res = obj;
         for (fname, args) in filters {