diff --git a/scripts/expr_parser.py b/scripts/expr_parser.py
index c21112472e3..a9bd4d73fc8 100644
--- a/scripts/expr_parser.py
+++ b/scripts/expr_parser.py
@@ -63,7 +63,7 @@ def t_INTEGER(t):
     return t
 
 def t_STR(t):
-    r'\"([^\\\n]|(\\.))*?\"'
+    r'\"([^\\\n]|(\\.))*?\"|\'([^\\\n]|(\\.))*?\''
     # nip off the quotation marks
     t.value = t.value[1:-1]
     return t