feat: add prepared error/null ok returns from gen_* functions

src/compiler/generator/gen_unary_logical.c

@@ -0,0 +1,23 @@
+#include <common/fzl_opcodes.h>
+#include <common/fzl_types.h>
+#include <compiler/fzl_parser.h>
+#include <compiler/internals/gen.h>
+#include <stdio.h>
+
+// Currently, only NOT operator
+gen_res_t gen_unary_logical(fzl_gen_t *gen, fzl_node_t *node)
+{
+  if (!gen || !node)
+    return gen_error;
+
+  gen_res_t operand_res = gen_common(gen, node->unary_op.operand);
+  if (operand_res.error)
+    return gen_error;
+
+  if (node->type == FZL_NODETYPE_NOT)
+    gen_op(gen, FZL_OPCODE_NOT);
+  else
+    return gen_error;
+
+  return (gen_res_t){.error = false, .type = FZL_TYPE_BOOL, .classname = NULL};
+}