node.h

/**
 * @file node.h
 *
 * Functions related to nodes in the AST.
 */
#ifndef PRISM_NODE_H
#define PRISM_NODE_H

#include "prism/defines.h"
#include "prism/parser.h"
#include "prism/util/pm_buffer.h"

/**
 * Attempts to grow the node list to the next size. If there is already
 * capacity in the list, this function does nothing. Otherwise it reallocates
 * the list to be twice as large as it was before. If the reallocation fails,
 * this function returns false, otherwise it returns true.
 *
 * @param list The list to grow.
 * @return True if the list was successfully grown, false otherwise.
 */
bool pm_node_list_grow(pm_node_list_t *list);

/**
 * Append a new node onto the end of the node list.
 *
 * @param list The list to append to.
 * @param node The node to append.
 */
void pm_node_list_append(pm_node_list_t *list, pm_node_t *node);

/**
 * Prepend a new node onto the beginning of the node list.
 *
 * @param list The list to prepend to.
 * @param node The node to prepend.
 */
void
pm_node_list_prepend(pm_node_list_t *list, pm_node_t *node);

/**
 * Free the internal memory associated with the given node list.
 *
 * @param list The list to free.
 */
void pm_node_list_free(pm_node_list_t *list);

/**
 * Deallocate a node and all of its children.
 *
 * @param parser The parser that owns the node.
 * @param node The node to deallocate.
 */
PRISM_EXPORTED_FUNCTION void pm_node_destroy(pm_parser_t *parser, struct pm_node *node);

/**
 * This struct stores the information gathered by the pm_node_memsize function.
 * It contains both the memory footprint and additionally metadata about the
 * shape of the tree.
 */
typedef struct {
    /** The total memory footprint of the node and all of its children. */
    size_t memsize;

    /** The number of children the node has. */
    size_t node_count;
} pm_memsize_t;

/**
 * Calculates the memory footprint of a given node.
 *
 * @param node The node to calculate the memory footprint of.
 * @param memsize The memory footprint of the node and all of its children.
 */
PRISM_EXPORTED_FUNCTION void pm_node_memsize(pm_node_t *node, pm_memsize_t *memsize);

/**
 * Returns a string representation of the given node type.
 *
 * @param node_type The node type to convert to a string.
 * @return A string representation of the given node type.
 */
PRISM_EXPORTED_FUNCTION const char * pm_node_type_to_str(pm_node_type_t node_type);

/**
 * Visit each of the nodes in this subtree using the given visitor callback. The
 * callback function will be called for each node in the subtree. If it returns
 * false, then that node's children will not be visited. If it returns true,
 * then the children will be visited. The data parameter is treated as an opaque
 * pointer and is passed to the visitor callback for consumers to use as they
 * see fit.
 *
 * As an example:
 *
 * ```c
 * #include "prism.h"
 *
 * bool visit(const pm_node_t *node, void *data) {
 *     size_t *indent = (size_t *) data;
 *     for (size_t i = 0; i < *indent * 2; i++) putc(' ', stdout);
 *     printf("%s\n", pm_node_type_to_str(node->type));
 *
 *     size_t next_indent = *indent + 1;
 *     size_t *next_data = &next_indent;
 *     pm_visit_child_nodes(node, visit, next_data);
 *
 *     return false;
 * }
 *
 * int main(void) {
 *     const char *source = "1 + 2; 3 + 4";
 *     size_t size = strlen(source);
 *
 *     pm_parser_t parser;
 *     pm_options_t options = { 0 };
 *     pm_parser_init(&parser, (const uint8_t *) source, size, &options);
 *
 *     size_t indent = 0;
 *     pm_node_t *node = pm_parse(&parser);
 *
 *     size_t *data = &indent;
 *     pm_visit_node(node, visit, data);
 *
 *     pm_node_destroy(&parser, node);
 *     pm_parser_free(&parser);
 *     return EXIT_SUCCESS;
 * }
 * ```
 *
 * @param node The root node to start visiting from.
 * @param visitor The callback to call for each node in the subtree.
 * @param data An opaque pointer that is passed to the visitor callback.
 */
PRISM_EXPORTED_FUNCTION void pm_visit_node(const pm_node_t *node, bool (*visitor)(const pm_node_t *node, void *data), void *data);

/**
 * Visit the children of the given node with the given callback. This is the
 * default behavior for walking the tree that is called from pm_visit_node if
 * the callback returns true.
 *
 * @param node The node to visit the children of.
 * @param visitor The callback to call for each child node.
 * @param data An opaque pointer that is passed to the visitor callback.
 */
PRISM_EXPORTED_FUNCTION void pm_visit_child_nodes(const pm_node_t *node, bool (*visitor)(const pm_node_t *node, void *data), void *data);

#endif