feat: optimize VM using dispatch table

src/vm/handlers/group_ctx.c

@@ -0,0 +1,127 @@
+#include <vm/fzl_vm.h>
+#include <vm/internals/opcode.h>
+
+// Allocate environment table and increment scope level
+int op_mk_envtable(fzl_vm_t *vm)
+{
+  vm->estack[vm->etop++] = fzl_mkenv();
+  return 0;
+}
+
+// Remove environment table and decrement scope level
+int op_rm_envtable(fzl_vm_t *vm)
+{
+  fzl_freeenv(vm->estack[--vm->etop]);
+  return 0;
+}
+
+// Store new variable
+int op_store(fzl_vm_t *vm)
+{
+  if (vm->dtop < 1)
+  {
+    snprintf(last_err, sizeof(last_err),
+             "runtime error - expected var name in data stack");
+    print_err_data(vm);
+    return -1;
+  }
+
+  fzl_value_t varname = vm->dstack[--vm->dtop];
+  fzl_env_storevalue(vm->estack[vm->etop - 1], (char *)varname.as.s.value,
+                     (fzl_value_t){});
+
+  return 0;
+}
+
+// Lookup environment(s) for variable using name on stack
+int op_lookup_env(fzl_vm_t *vm)
+{
+  if (vm->dtop < 1)
+  {
+    snprintf(last_err, sizeof(last_err),
+             "runtime error - LOOKUP_ENV: empty data stack");
+    print_err_data(vm);
+    return -1;
+  }
+
+  fzl_value_t val = vm->dstack[--vm->dtop];
+  fzl_value_t env_val;
+  bool result;
+  for (ssize_t i = vm->etop - 1; i >= 0; i--)
+  {
+    if ((result =
+             fzl_env_lookup(vm->estack[i], (char *)val.as.s.value, &env_val)))
+      break;
+  }
+  vm->dstack[vm->dtop++] = env_val;
+
+  return 0;
+}
+
+// Writable variable value
+int op_write(fzl_vm_t *vm)
+{
+  if (vm->dtop < 2)
+  {
+    snprintf(last_err, sizeof(last_err),
+             "runtime error - expected 2 values in data stack");
+    print_err_data(vm);
+    return -1;
+  }
+
+  fzl_value_t writevar = vm->dstack[--vm->dtop];
+  fzl_value_t value    = vm->dstack[--vm->dtop];
+
+  char *wrname = (char *)writevar.as.s.value;
+  bool wrfound;
+  fzl_value_t wrenv;
+  ssize_t wrlvl = -1;
+  for (ssize_t i = vm->etop - 1; i >= 0; i--)
+  {
+    if ((wrfound = fzl_env_lookup(vm->estack[i], wrname, &wrenv)))
+    {
+      wrlvl = i;
+      break;
+    }
+  }
+
+  if (wrlvl <= -1)
+  {
+    snprintf(last_err, sizeof(last_err),
+             "runtime error - name '%s' not found in this scope", wrname);
+    print_err_data(vm);
+    return -1;
+  }
+
+  fzl_vm_env_wresult_t wresult =
+      fzl_env_writevalue(vm->estack[wrlvl], (char *)wrname, value);
+  if (wresult != FZL_VM_ENV_WRESULT_OK)
+  {
+    switch (wresult)
+    {
+      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;
+    }
+  }
+
+  return 0;
+}