Feb 15th 2023 update

external/graphqlparser/c/GraphQLAstVisitor.h

@@ -0,0 +1,53 @@
+/**
+ * Copyright 2019-present, GraphQL Foundation
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#pragma once
+
+#include "c/GraphQLAst.h"
+#include "c/GraphQLAstForEachConcreteType.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+  
+#define TYPEDEFS(type, snake_type)                                      \
+  typedef int (*visit_##snake_type##_func)(const struct GraphQLAst##type *snake_type, void *user_data); \
+  typedef void (*end_visit_##snake_type##_func)(const struct GraphQLAst##type *snake_type, void *user_data);
+
+FOR_EACH_CONCRETE_TYPE(TYPEDEFS)
+
+#define FUNC_MEMBER(type, snake_type)           \
+  visit_##snake_type##_func visit_##snake_type; \
+  end_visit_##snake_type##_func end_visit_##snake_type;
+/**
+ * Functions to be called when particular AST nodes are encountered.
+ * visit_* functions are called in pre-order, and may return non-zero to
+ * continue recursing into children (if any), or zero to skip them. end_visit_*
+ * functions are called in post-order. Any particular function may be set to
+ * NULL to indicate that the caller is not interested in the corresponding type
+ * of AST node. (NULL visit_* functions act as though they simply returned
+ * non-zero.)
+ */
+struct GraphQLAstVisitorCallbacks {
+  FOR_EACH_CONCRETE_TYPE(FUNC_MEMBER)
+};
+
+struct GraphQLAstNode;
+
+/**
+ * Walk the AST rooted at the given node, issuing callbacks from the given
+ * callbacks struct as appropriate. userData will be passed as the userData
+ * argument to each callback.
+ */
+void graphql_node_visit(const struct GraphQLAstNode *node,
+                        const struct GraphQLAstVisitorCallbacks *callbacks,
+                        void *userData);
+
+#ifdef __cplusplus
+}
+#endif
+