forget to return in `str_to_lower`

1 files changed, 1 insertions, 0 deletions

diff --git a/parser.cpp b/parser.cpp
index a00f3f4..b27a8dc 100644
--- a/parser.cpp
+++ b/parser.cpp
@@ -48,6 +48,7 @@ string str_to_lower(string str) {
     for (size_t i = 0; i < len; i++)
         if ('A' <= str[i] && str[i] <= 'Z')
             str[i] -= 'A' - 'a';
+    return str;
 }
 
 bool Tokenizor::get_token(string &ret) {