test program stack viz

runtime/main.cpp

@@ -171,5 +171,7 @@ int main()
             .code_coverage = true,
         });
     vm.run_until_done();
-    std::cout << std::format("done\n{}\n", vm.stack_repr_string());
+    std::cout << std::format("done\n{}\n", vm.stack_repr_string(4));
+    auto flame_graph = vm.flame_graph_json();
+    std::cout << std::format("flame graph: {}\n", flame_graph);
 }

runtime/vm.cpp

@@ -86,7 +86,7 @@ void VM::run_n_instructions(size_t amount)
 void VM::run_instruction()
 {
     std::cout << std::format("    {:>4}: {:<12}{}\n", this->pc,
-        maybe_op_to_string(this->program[this->pc]), stack_repr_string());
+        maybe_op_to_string(this->program[this->pc]), stack_repr_string(4));
     auto op = eat_op();
     switch (op) {
         case Op::Nop:

runtime/vm.hpp

@@ -156,16 +156,20 @@ public:
         return this->stack;
     }
 
-    inline auto stack_repr_string() const -> std::string
+    inline auto stack_repr_string(size_t max_items) const -> std::string
     {
         auto result = std::string();
         result += "→";
         const auto& stack = view_stack();
-        for (size_t i = 0; i < stack.size(); ++i) {
+        for (size_t i = 0; i < stack.size() and i < max_items; ++i) {
             if (i != 0) {
                 result += " ";
             }
-            result += stack[stack.size() - i - 1].to_repr_string();
+            result += std::format(
+                "{:<11}", stack[stack.size() - i - 1].to_repr_string());
+        }
+        if (stack.size() >= max_items) {
+            result += std::format(" ... + {}", stack.size() - max_items + 1);
         }
         return result;
     }