Expose pm_node_list_append and pm_parser_constant_insert

include/prism/internal/node.h

@@ -14,14 +14,18 @@
 #define PM_LOCATION_END(location_) ((location_)->start + (location_)->length)
 
 /*
- * Slow path for pm_node_list_append: grow the list and append the node.
- * Do not call directly — use pm_node_list_append instead.
+ * Slow path for pm_node_list_append_inline: grow the list and append the node.
+ * Do not call directly — use pm_node_list_append_inline instead.
  */
 void pm_node_list_append_slow(pm_arena_t *arena, pm_node_list_t *list, pm_node_t *node);
 
-/* Append a new node onto the end of the node list. */
+/*
+ * Append a new node onto the end of the node list, handling the common case
+ * inline and growing the list through pm_node_list_append_slow. This is the
+ * version for prism's own code; others call the exported pm_node_list_append.
+ */
 static PRISM_FORCE_INLINE void
-pm_node_list_append(pm_arena_t *arena, pm_node_list_t *list, pm_node_t *node) {
+pm_node_list_append_inline(pm_arena_t *arena, pm_node_list_t *list, pm_node_t *node) {
     if (list->size < list->capacity) {
         list->nodes[list->size++] = node;
     } else {

include/prism/node.h

@@ -22,6 +22,18 @@ extern "C" {
 #define PM_NODE_LIST_FOREACH(list, index, node) \
     for (size_t index = 0; index < (list)->size && ((node) = (list)->nodes[index]); index++)
 
+/**
+ * Append a node to the end of a node list. If the list is full, its storage is
+ * grown by allocating from the given arena, so the arena must live as long as
+ * the list does. For a list in a parsed tree, that is the arena that was passed
+ * to pm_parser_new.
+ *
+ * @param arena The arena to allocate the list's storage from.
+ * @param list The list to append to.
+ * @param node The node to append.
+ */
+PRISM_EXPORTED_FUNCTION void pm_node_list_append(pm_arena_t *arena, pm_node_list_t *list, pm_node_t *node) PRISM_NONNULL(1, 2, 3);
+
 /**
  * Returns a string representation of the given node type.
  *

include/prism/parser.h

@@ -154,6 +154,24 @@ PRISM_EXPORTED_FUNCTION const pm_string_t * pm_parser_filepath(const pm_parser_t
  */
 PRISM_EXPORTED_FUNCTION pm_constant_id_t pm_parser_constant_find(const pm_parser_t *parser, const uint8_t *start, size_t length) PRISM_NONNULL(1, 2);
 
+/**
+ * Add a constant to the parser's constant pool, for naming a node that was not
+ * parsed from the source. If the constant is already in the pool, its existing
+ * id is returned. Otherwise the parser copies the bytes, so they only need to
+ * remain valid for the duration of the call.
+ *
+ * Adding a constant makes the pool larger, so a cache with one entry per
+ * constant built beforehand from pm_parser_constants_size and
+ * pm_parser_constant_at does not cover it. Build such caches after adding any
+ * constants.
+ *
+ * @param parser the parser whose constant pool we want to add to
+ * @param start a pointer to the start of the string to add
+ * @param length the length of the string to add
+ * @returns the id of the constant
+ */
+PRISM_EXPORTED_FUNCTION pm_constant_id_t pm_parser_constant_insert(pm_parser_t *parser, const uint8_t *start, size_t length) PRISM_NONNULL(1, 2);
+
 /**
  * Returns the frozen string literal value of the parser, as determined by the
  * frozen_string_literal magic comment or the option set on the parser.

rust/ruby-prism-sys/build/main.rs

@@ -199,6 +199,7 @@ fn generate_bindings(ruby_include_path: &Path, clang_args: &[String], layout_tes
         .allowlist_function("pm_magic_comment_key")
         .allowlist_function("pm_magic_comment_next")
         .allowlist_function("pm_magic_comment_value")
+        .allowlist_function("pm_node_list_append")
         .allowlist_function("pm_options_command_line_set")
         .allowlist_function("pm_options_encoding_locked_set")
         .allowlist_function("pm_options_encoding_set")
@@ -220,6 +221,7 @@ fn generate_bindings(ruby_include_path: &Path, clang_args: &[String], layout_tes
         .allowlist_function("pm_parser_comments_size")
         .allowlist_function("pm_parser_constant")
         .allowlist_function("pm_parser_constant_at")
+        .allowlist_function("pm_parser_constant_insert")
         .allowlist_function("pm_parser_constants_size")
         .allowlist_function("pm_parser_data_loc")
         .allowlist_function("pm_parser_errors_first")

src/parser.c

@@ -106,6 +106,19 @@ pm_parser_constant_find(const pm_parser_t *parser, const uint8_t *start, size_t
     return pm_constant_pool_find(&parser->constant_pool, start, length);
 }
 
+/**
+ * Add a constant to the parser's constant pool, copying its bytes into the
+ * parser's arena only if the constant is not already there.
+ */
+pm_constant_id_t
+pm_parser_constant_insert(pm_parser_t *parser, const uint8_t *start, size_t length) {
+    pm_constant_id_t id = pm_constant_pool_find(&parser->constant_pool, start, length);
+    if (id != PM_CONSTANT_ID_UNSET) return id;
+
+    const uint8_t *copy = (const uint8_t *) pm_arena_memdup(&parser->metadata_arena, start, length, PRISM_ALIGNOF(uint8_t));
+    return pm_constant_pool_insert_constant(&parser->metadata_arena, &parser->constant_pool, copy, length);
+}
+
 /**
  * Returns the frozen string literal value of the parser.
  */