improved first pass by using prog vector size instead of pc; added pc offset vector clear to reset

interpreter.cpp

@@ -24,6 +24,7 @@ void interpreter::reset() {
     _labels.clear();
     _vars.clear();
     _calls.clear();
+    _pc_offsets.clear();
     _pc = 0;
 }
 
@@ -33,14 +34,12 @@ std::string interpreter::eval(std::istream& in, bool& done) {
     done = false;
 
     // first pass: read program & resolve labels
-    for (std::string line; std::getline(in, line); ++_pc) {
+    for (std::string line; std::getline(in, line);) {
         if (line[0] == ':') { // check label definition
-            _labels.emplace(line.substr(1), _pc);
+            _labels.emplace(line.substr(1), _prog.size());
-            _pc_offsets.push_back(_pc);
+            _pc_offsets.push_back(_prog.size());
-            _pc--; // we'll lose this line
         } else if (line[0] == '#') { // check comment
-            _pc_offsets.push_back(_pc);
+            _pc_offsets.push_back(_prog.size());
-            _pc--; // we'll lose this line
         } else {
             _prog.push_back(line);
         }