Overhaul of command parsing

luprex/core/cpp/util.cpp

@@ -142,6 +142,16 @@ StringVec split(const std::string &s, char sep) {
     return result;
 }
 
+std::string join(const StringVec &strs, const std::string &sep) {
+    if (strs.empty()) return "";
+    std::ostringstream oss;
+    oss << strs[0];
+    for (int i = 1; i < strs.size(); i++) {
+        oss << sep << strs[i];
+    }
+    return oss.str();
+}
+
 std::string repeat_string(const std::string &a, int n) {
     int len = a.size();
     std::string result(len * n, ' ');