diff --git a/cli/src/generate/prepare_grammar/expand_tokens.rs b/cli/src/generate/prepare_grammar/expand_tokens.rs
index 9e2cf9fe..67813030 100644
--- a/cli/src/generate/prepare_grammar/expand_tokens.rs
+++ b/cli/src/generate/prepare_grammar/expand_tokens.rs
@@ -12,7 +12,7 @@ use std::i32;
 
 lazy_static! {
     static ref CURLY_BRACE_REGEX: Regex =
-        Regex::new(r#"(^|[^\\])\{([^}]*[^0-9,}][^}]*)\}"#).unwrap();
+        Regex::new(r#"(^|[^\\])\{([^}]*[^0-9A-F,}][^}]*)\}"#).unwrap();
 }
 
 const ALLOWED_REDUNDANT_ESCAPED_CHARS: [char; 4] = ['!', '\'', '"', '/'];