diff --git a/src/core/shuntingYard.cpp b/src/core/shuntingYard.cpp
index b03f1ecd5..6f37dc3d3 100644
--- a/src/core/shuntingYard.cpp
+++ b/src/core/shuntingYard.cpp
@@ -21,7 +21,7 @@
 #include "emsesp.h"
 
 #include "shuntingYard.h"
-#include <regex>
+// #include <regex>
 
 namespace emsesp {
 
@@ -334,9 +334,8 @@ std::deque<Token> shuntingYard(const std::deque<Token> & tokens) {
 
 // check if string is a number
 bool isnum(const std::string & s) {
-    std::regex r("^[+-]?(\\d+\\.?\\d*)$");
-    return std::regex_match(s, r);
-    /*
+    // std::regex r("^[+-]?(\\d+\\.?\\d*)$");
+    // return std::regex_match(s, r);
     if (s.empty() || s.find_first_of("0123456789") == std::string::npos) {
         return false;
     }
@@ -344,7 +343,6 @@ bool isnum(const std::string & s) {
         return true;
     }
     return false;
-    */
 }
 
 
@@ -833,4 +831,4 @@ std::string compute(const std::string & expr) {
     return calculate(expr_new);
 }
 
-} // namespace emsesp
\ No newline at end of file
+} // namespace emsesp