feat: add first hard example

Hard example tests all actual language features. For now its:
- Classes
- Methods
- Recursive calls
- Object move and borrowing

exl/hard-1.fzs

@@ -0,0 +1,61 @@
+class Node
+{
+  int value;
+  Node next;
+
+  fn append(int val) Node
+  {
+    if (this.next == null)
+    {
+      Node tail = new Node;
+      tail.value = val;
+      tail.next = null;
+      this.next = tail;
+      return this;
+    }
+
+    this.next = this.next.append(val);
+    return this;
+  }
+
+  fn sum() int
+  {
+    if (this.next == null)
+      return this.value;
+
+    return this.value + this.next.sum();
+  }
+
+  fn printList()
+  {
+    printline(this.value);
+    if (this.next != null)
+      this.next.printList();
+  }
+}
+
+fn createList(int count) Node
+{
+  if (count <= 0)
+    return null;
+
+  Node head = new Node;
+  head.value = count;
+  head.next = createList(count - 1);
+  return head;
+}
+
+printline("===== Test 1: factory & recursive escaping =====");
+Node list = createList(3);
+printline("Elements:");
+list.printList();
+
+printline("===== Test 2: mutation & methods =====");
+int total = list.sum();
+printline("Sum of elements:");
+printline(total);
+
+if (total == 16)
+  printline("Tests passed!");
+else printline("Tests failed");
+

src/vm/fzl_vm.c

@@ -147,6 +147,55 @@ void print_object(fzl_vm_object_t *obj)
   printf(">\n");
 }
 
+void print_err_data(fzl_vm_t *vm)
+{
+  printf("===== ERROR =====\n");
+  printf("> Caused on IP: %zu\n", vm->ip);
+
+  printf("\n> Data stack:\n");
+  for (ssize_t i = vm->dtop - 1; i >= 0; i--)
+  {
+    printf("\t> [%d] ", vm->dstack[i].type);
+    switch (vm->dstack[i].type)
+    {
+      case FZL_TYPE_OBJECT:
+        printf("ref: %p\n", vm->dstack[i].as.obj);
+        break;
+      case FZL_TYPE_STRING:
+        printf("str: '%s'\n", vm->dstack[i].as.s.value);
+        break;
+      case FZL_TYPE_NULL:
+        printf("<null>\n");
+        break;
+      default:
+        printf("%lu\n", vm->dstack[i].as.u);
+        break;
+    }
+  }
+
+  printf("\n> Environments:\n");
+  for (ssize_t i = vm->etop - 1; i >= 0; i--)
+  {
+    fzl_vm_env_t *env = vm->estack[i];
+    printf("\t> [%zd] %p:\n", i, env);
+
+    printf("\t\t> Owned objects (%zu/%zu):\n", env->owned_objects_count,
+           env->owned_objects_remainder);
+    for (size_t j = 0; j < env->owned_objects_count; j++)
+      printf("\t\t\t> ref: %p (entries: %zu)\n", env->owned_objects[j],
+             env->owned_objects[j]->values_count);
+
+    printf("\t\t> Local entries (%zu/%zu):\n", env->size, env->remainder);
+    for (size_t j = 0; j < env->size; j++)
+      printf("\t\t\t> [%d] %s = %lu\n", env->table[j].value.type,
+             env->table[j].name, env->table[j].value.as.u);
+  }
+
+  printf("\n> Call stack:\n");
+  for (ssize_t i = vm->ctop - 1; i >= 0; i--)
+    printf("\t> [%zd] %lu\n", i, vm->cstack[i]);
+}
+
 int fzl_vm_run(fzl_vm_t *vm)
 {
   if (!vm)
@@ -168,6 +217,7 @@ int fzl_vm_run(fzl_vm_t *vm)
         {
           snprintf(last_err, sizeof(last_err),
                    "runtime error - expected two values in data stack");
+          print_err_data(vm);
           return -1;
         }
         fzl_value_t left  = vm->dstack[--vm->dtop];
@@ -185,6 +235,7 @@ int fzl_vm_run(fzl_vm_t *vm)
         {
           snprintf(last_err, sizeof(last_err),
                    "runtime error - expected two values in data stack");
+          print_err_data(vm);
           return -1;
         }
         fzl_value_t left  = vm->dstack[--vm->dtop];
@@ -202,6 +253,7 @@ int fzl_vm_run(fzl_vm_t *vm)
         {
           snprintf(last_err, sizeof(last_err),
                    "runtime error - expected two values in data stack");
+          print_err_data(vm);
           return -1;
         }
         fzl_value_t left  = vm->dstack[--vm->dtop];
@@ -218,6 +270,7 @@ int fzl_vm_run(fzl_vm_t *vm)
         {
           snprintf(last_err, sizeof(last_err),
                    "runtime error - expected two values in data stack");
+          print_err_data(vm);
           return -1;
         }
         fzl_value_t left  = vm->dstack[--vm->dtop];
@@ -228,19 +281,22 @@ int fzl_vm_run(fzl_vm_t *vm)
         break;
       }
 
+      // NOTE: make recursive owning transfer for nested objects!
       case FZL_OPCODE_ESCAPE_OBJECT:
       {
         if (vm->dtop < 1)
         {
           snprintf(last_err, sizeof(last_err),
                    "runtime error - missing value in data stack");
+          print_err_data(vm);
           return -1;
         }
         fzl_value_t obj = vm->dstack[--vm->dtop];
-        if (obj.type != FZL_TYPE_OBJECT)
+        if (obj.type != FZL_TYPE_OBJECT && obj.type < FZL_TYPE_INT8)
         {
           snprintf(last_err, sizeof(last_err),
                    "runtime error - cannot escape non-object type");
+          print_err_data(vm);
           return -1;
         }
 
@@ -250,10 +306,13 @@ int fzl_vm_run(fzl_vm_t *vm)
         {
           snprintf(last_err, sizeof(last_err),
                    "runtime error - cannot escape object from global env");
+          print_err_data(vm);
           return -1;
         }
 
         bool found = false;
+        if (obj.as.u != 0)
+        {
           for (size_t i = 0; i < current->owned_objects_count; i++)
           {
             if (obj.as.obj == current->owned_objects[i])
@@ -263,6 +322,7 @@ int fzl_vm_run(fzl_vm_t *vm)
               break;
             }
           }
+        }
 
         if (found)
         {
@@ -310,6 +370,7 @@ int fzl_vm_run(fzl_vm_t *vm)
         {
           snprintf(last_err, sizeof(last_err),
                    "runtime error - expected value in data stack");
+          print_err_data(vm);
           return -1;
         }
 
@@ -321,6 +382,7 @@ int fzl_vm_run(fzl_vm_t *vm)
               last_err, sizeof(last_err),
               "runtime error - cannot access field #%lu of non-object type",
               field_slot);
+          print_err_data(vm);
           return -1;
         }
 
@@ -329,6 +391,7 @@ int fzl_vm_run(fzl_vm_t *vm)
         {
           snprintf(last_err, sizeof(last_err),
                    "runtime error - cannot access field #%lu", field_slot);
+          print_err_data(vm);
           return -1;
         }
 
@@ -342,6 +405,7 @@ int fzl_vm_run(fzl_vm_t *vm)
         {
           snprintf(last_err, sizeof(last_err),
                    "runtime error - expected two values in data stack");
+          print_err_data(vm);
           return -1;
         }
 
@@ -354,6 +418,7 @@ int fzl_vm_run(fzl_vm_t *vm)
               last_err, sizeof(last_err),
               "runtime error - cannot access field #%lu of non-object type",
               field_slot);
+          print_err_data(vm);
           return -1;
         }
 
@@ -362,6 +427,7 @@ int fzl_vm_run(fzl_vm_t *vm)
         {
           snprintf(last_err, sizeof(last_err),
                    "runtime error - cannot access field #%lu", field_slot);
+          print_err_data(vm);
           return -1;
         }
 
@@ -383,6 +449,7 @@ int fzl_vm_run(fzl_vm_t *vm)
         {
           snprintf(last_err, sizeof(last_err),
                    "runtime error - no place to jump");
+          print_err_data(vm);
           return -1;
         }
 
@@ -395,6 +462,7 @@ int fzl_vm_run(fzl_vm_t *vm)
         {
           snprintf(last_err, sizeof(last_err),
                    "runtime error - expected two values in data stack");
+          print_err_data(vm);
           return -1;
         }
 
@@ -409,6 +477,7 @@ int fzl_vm_run(fzl_vm_t *vm)
         {
           snprintf(last_err, sizeof(last_err),
                    "runtime error - expected two values in data stack");
+          print_err_data(vm);
           return -1;
         }
 
@@ -423,6 +492,7 @@ int fzl_vm_run(fzl_vm_t *vm)
         {
           snprintf(last_err, sizeof(last_err),
                    "runtime error - expected two values in data stack");
+          print_err_data(vm);
           return -1;
         }
 
@@ -437,6 +507,7 @@ int fzl_vm_run(fzl_vm_t *vm)
         {
           snprintf(last_err, sizeof(last_err),
                    "runtime error - expected two values in data stack");
+          print_err_data(vm);
           return -1;
         }
 
@@ -451,6 +522,7 @@ int fzl_vm_run(fzl_vm_t *vm)
         {
           snprintf(last_err, sizeof(last_err),
                    "runtime error - expected two values in data stack");
+          print_err_data(vm);
           return -1;
         }
 
@@ -465,6 +537,7 @@ int fzl_vm_run(fzl_vm_t *vm)
         {
           snprintf(last_err, sizeof(last_err),
                    "runtime error - expected two values in data stack");
+          print_err_data(vm);
           return -1;
         }
 
@@ -479,6 +552,7 @@ int fzl_vm_run(fzl_vm_t *vm)
         {
           snprintf(last_err, sizeof(last_err),
                    "runtime error - expected value in data stack");
+          print_err_data(vm);
           return -1;
         }
 
@@ -492,6 +566,7 @@ int fzl_vm_run(fzl_vm_t *vm)
         {
           snprintf(last_err, sizeof(last_err),
                    "runtime error - expected value in data stack");
+          print_err_data(vm);
           return -1;
         }
 
@@ -510,6 +585,7 @@ int fzl_vm_run(fzl_vm_t *vm)
         {
           snprintf(last_err, sizeof(last_err),
                    "runtime error - expected two values in data stack");
+          print_err_data(vm);
           return -1;
         }
 
@@ -524,6 +600,7 @@ int fzl_vm_run(fzl_vm_t *vm)
         {
           snprintf(last_err, sizeof(last_err),
                    "runtime error - expected two values in data stack");
+          print_err_data(vm);
           return -1;
         }
 
@@ -538,6 +615,7 @@ int fzl_vm_run(fzl_vm_t *vm)
         {
           snprintf(last_err, sizeof(last_err),
                    "runtime error - expected var name in data stack");
+          print_err_data(vm);
           return -1;
         }
 
@@ -552,6 +630,7 @@ int fzl_vm_run(fzl_vm_t *vm)
         {
           snprintf(last_err, sizeof(last_err),
                    "runtime error - expected 2 values in data stack");
+          print_err_data(vm);
           return -1;
         }
 
@@ -567,21 +646,25 @@ int fzl_vm_run(fzl_vm_t *vm)
             case FZL_VM_ENV_WRESULT_ERR:
               snprintf(last_err, sizeof(last_err),
                        "runtime error - failed to write variable");
+              print_err_data(vm);
               return -1;
 
             case FZL_VM_ENV_WRESULT_ERR_EXISTS:
               snprintf(last_err, sizeof(last_err),
                        "runtime error - redefenition of '%s'",
                        writevar.as.s.value);
+              print_err_data(vm);
               return -1;
 
             case FZL_VM_ENV_WRESULT_ERR_NOT_FOUND:
               snprintf(last_err, sizeof(last_err),
                        "runtime error - cannot find name '%s'",
                        writevar.as.s.value);
+              print_err_data(vm);
               return -1;
 
             default:
+              print_err_data(vm);
               return -1;
           }
         }
@@ -605,6 +688,7 @@ int fzl_vm_run(fzl_vm_t *vm)
         {
           snprintf(last_err, sizeof(last_err),
                    "runtime error - LOOKUP_ENV: empty data stack");
+          print_err_data(vm);
           return -1;
         }
 
@@ -647,6 +731,7 @@ int fzl_vm_run(fzl_vm_t *vm)
         {
           snprintf(last_err, sizeof(last_err),
                    "runtime error - undefined builtin %lu", fn_id);
+          print_err_data(vm);
           return -1;
         }
       }
@@ -658,6 +743,7 @@ int fzl_vm_run(fzl_vm_t *vm)
         if (vm->consts_count <= cn)
         {
           snprintf(last_err, sizeof(last_err), "runtime error - unknown const");
+          print_err_data(vm);
           return -1;
         }
         fzl_const_t c = vm->consts[cn];
@@ -673,6 +759,7 @@ int fzl_vm_run(fzl_vm_t *vm)
         {
           snprintf(last_err, sizeof(last_err),
                    "runtime error - expected 2 values in stack");
+          print_err_data(vm);
           return -1;
         }
         fzl_value_t add1 = vm->dstack[--vm->dtop];
@@ -686,6 +773,7 @@ int fzl_vm_run(fzl_vm_t *vm)
         {
           snprintf(last_err, sizeof(last_err),
                    "runtime error - expected 2 values in stack");
+          print_err_data(vm);
           return -1;
         }
         fzl_value_t sub2 = vm->dstack[--vm->dtop];
@@ -699,6 +787,7 @@ int fzl_vm_run(fzl_vm_t *vm)
         {
           snprintf(last_err, sizeof(last_err),
                    "runtime error - expected 2 values in stack");
+          print_err_data(vm);
           return -1;
         }
         fzl_value_t mul1 = vm->dstack[--vm->dtop];
@@ -712,6 +801,7 @@ int fzl_vm_run(fzl_vm_t *vm)
         {
           snprintf(last_err, sizeof(last_err),
                    "runtime error - expected 2 values in stack");
+          print_err_data(vm);
           return -1;
         }
         fzl_value_t div1 = vm->dstack[--vm->dtop];
@@ -725,6 +815,7 @@ int fzl_vm_run(fzl_vm_t *vm)
         {
           snprintf(last_err, sizeof(last_err),
                    "runtime error - expected 2 values in stack");
+          print_err_data(vm);
           return -1;
         }
         fzl_value_t pow2 = vm->dstack[--vm->dtop];
@@ -745,6 +836,7 @@ int fzl_vm_run(fzl_vm_t *vm)
         {
           snprintf(last_err, sizeof(last_err),
                    "runtime error - expected 2 values in stack");
+          print_err_data(vm);
           return -1;
         }
         fzl_value_t mod1 = vm->dstack[--vm->dtop];
@@ -758,6 +850,7 @@ int fzl_vm_run(fzl_vm_t *vm)
         {
           snprintf(last_err, sizeof(last_err),
                    "runtime error - expected value in stack");
+          print_err_data(vm);
           return -1;
         }
         fzl_value_t neg_n = vm->dstack[--vm->dtop];
@@ -784,6 +877,7 @@ int fzl_vm_run(fzl_vm_t *vm)
       default:
         snprintf(last_err, sizeof(last_err),
                  "runtime error - unknown opcode %u", opcode);
+        print_err_data(vm);
         return -1;
     }