Some additional checks for the MacOS workaround for Issue beltoforion…

…#116

parser/mpValReader.cpp

@@ -36,7 +36,7 @@
 #include "mpError.h"
 
 #ifdef __APPLE__
-#include<regex>
+#include <regex>
 #endif
 
 
@@ -69,9 +69,11 @@ bool DblValReader::IsValue(const char_type* a_szExpr, int& a_iPos, Value& a_Val)
 	{
 #ifdef __APPLE__
 		// Workaround for clang not parsing strings like 3i with std::stringstream(imaginary numbers)
-		// See https://discourse.llvm.org/t/different-behavior-from-stringstream-operator-in-libc-vs-libstdc/57482   
+		// See https://discourse.llvm.org/t/different-behavior-from-stringstream-operator-in-libc-vs-libstdc/57482
+		// yields 3 groups if successful. The 2nd and 3rd groups when present together as in 3i or 2n is what
+		// clang does differently compared to gcc and visual studio
 		//			1	2	   3
-		std::regex pattern("(\\s*)(\\d*\\.*\\d*)(\\w*).*"); // yields 3 groups if successful 
+		std::regex pattern("(\\s*)(\\d+\\.*\\d*)(\\w+).*");
 		std::smatch match;
 		std::string str(a_szExpr+ a_iPos);
 		if (std::regex_match(str, match, pattern) && match.size() == 4 && match[3].length() == 1)