[Parser] Restore support of parameter expressions like pi*-0.25

src/quartz/parser/qasm_parser.cpp

@@ -250,6 +250,13 @@ int ParamParser::parse_expr(std::stringstream &ss, bool is_halved) {
     // Determines where the expression splits into terms, when applicable.
     // The right-most (last) deliminator will identify the next term to parse.
     size_t pos = token.find_last_of("+-");
+    while (pos != std::string::npos && pos > 0) {
+      if (token[pos - 1] == '*') {
+        // Case: t*-e (negative sign), ignored here
+        std::cout << pos << std::endl;
+        pos = token.find_last_of("+-", pos - 1);
+      }
+    }
 
     // Determines which case this corresponds to.
     int tid;