diff --git a/include/prism.h b/include/prism.h
index 08d216cbb5d..afd57483fd3 100644
--- a/include/prism.h
+++ b/include/prism.h
@@ -187,6 +187,16 @@ const char * pm_token_type_human(pm_token_type_t token_type);
  */
 PRISM_EXPORTED_FUNCTION void pm_parser_errors_format(const pm_parser_t *parser, pm_buffer_t *buffer, bool colorize);
 
+/**
+ * Visit each of the nodes in this subtree using the given visitor callback.
+ *
+ * @param node The node to visit.
+ * @param visitor The visitor callback to use. It should return `true` if the
+ *       visitor should continue visiting nodes, and `false` if it should stop.
+ * @param data The optional data to pass to the visitor.
+ */
+PRISM_EXPORTED_FUNCTION void pm_node_visit(const pm_node_t *node, bool (*visitor)(const pm_node_t *node, void *data), void *data);
+
 /**
  * @mainpage
  *
diff --git a/include/prism/util/pm_buffer.h b/include/prism/util/pm_buffer.h
index f0cca84af57..513633baa16 100644
--- a/include/prism/util/pm_buffer.h
+++ b/include/prism/util/pm_buffer.h
@@ -7,6 +7,7 @@
 #define PRISM_BUFFER_H
 
 #include "prism/defines.h"
+#include "prism/util/pm_char.h"
 
 #include <assert.h>
 #include <stdbool.h>
@@ -59,7 +60,7 @@ PRISM_EXPORTED_FUNCTION bool pm_buffer_init(pm_buffer_t *buffer);
  * @param buffer The buffer to get the value of.
  * @returns The value of the buffer.
  */
-PRISM_EXPORTED_FUNCTION char * pm_buffer_value(pm_buffer_t *buffer);
+PRISM_EXPORTED_FUNCTION char * pm_buffer_value(const pm_buffer_t *buffer);
 
 /**
  * Return the length of the buffer.
@@ -67,7 +68,7 @@ PRISM_EXPORTED_FUNCTION char * pm_buffer_value(pm_buffer_t *buffer);
  * @param buffer The buffer to get the length of.
  * @returns The length of the buffer.
  */
-PRISM_EXPORTED_FUNCTION size_t pm_buffer_length(pm_buffer_t *buffer);
+PRISM_EXPORTED_FUNCTION size_t pm_buffer_length(const pm_buffer_t *buffer);
 
 /**
  * Append the given amount of space as zeroes to the buffer.
@@ -145,6 +146,21 @@ void pm_buffer_prepend_string(pm_buffer_t *buffer, const char *value, size_t len
  */
 void pm_buffer_concat(pm_buffer_t *destination, const pm_buffer_t *source);
 
+/**
+ * Clear the buffer by reducing its size to 0. This does not free the allocated
+ * memory, but it does allow the buffer to be reused.
+ *
+ * @param buffer The buffer to clear.
+ */
+void pm_buffer_clear(pm_buffer_t *buffer);
+
+/**
+ * Strip the whitespace from the end of the buffer.
+ *
+ * @param buffer The buffer to strip.
+ */
+void pm_buffer_rstrip(pm_buffer_t *buffer);
+
 /**
  * Free the memory associated with the buffer.
  *
diff --git a/include/prism/util/pm_string.h b/include/prism/util/pm_string.h
index ddb153784f4..8a568a82380 100644
--- a/include/prism/util/pm_string.h
+++ b/include/prism/util/pm_string.h
@@ -124,6 +124,18 @@ size_t pm_string_memsize(const pm_string_t *string);
  */
 void pm_string_ensure_owned(pm_string_t *string);
 
+/**
+ * Compare the underlying lengths and bytes of two strings. Returns 0 if the
+ * strings are equal, a negative number if the left string is less than the
+ * right string, and a positive number if the left string is greater than the
+ * right string.
+ *
+ * @param left The left string to compare.
+ * @param right The right string to compare.
+ * @return The comparison result.
+ */
+int pm_string_compare(const pm_string_t *left, const pm_string_t *right);
+
 /**
  * Returns the length associated with the string.
  *
diff --git a/src/util/pm_buffer.c b/src/util/pm_buffer.c
index 0ae94454288..129bed52cd3 100644
--- a/src/util/pm_buffer.c
+++ b/src/util/pm_buffer.c
@@ -32,7 +32,7 @@ pm_buffer_init(pm_buffer_t *buffer) {
  * Return the value of the buffer.
  */
 char *
-pm_buffer_value(pm_buffer_t *buffer) {
+pm_buffer_value(const pm_buffer_t *buffer) {
     return buffer->value;
 }
 
@@ -40,7 +40,7 @@ pm_buffer_value(pm_buffer_t *buffer) {
  * Return the length of the buffer.
  */
 size_t
-pm_buffer_length(pm_buffer_t *buffer) {
+pm_buffer_length(const pm_buffer_t *buffer) {
     return buffer->length;
 }
 
@@ -181,6 +181,25 @@ pm_buffer_concat(pm_buffer_t *destination, const pm_buffer_t *source) {
     }
 }
 
+/**
+ * Clear the buffer by reducing its size to 0. This does not free the allocated
+ * memory, but it does allow the buffer to be reused.
+ */
+void
+pm_buffer_clear(pm_buffer_t *buffer) {
+    buffer->length = 0;
+}
+
+/**
+ * Strip the whitespace from the end of the buffer.
+ */
+void
+pm_buffer_rstrip(pm_buffer_t *buffer) {
+    while (buffer->length > 0 && pm_char_is_whitespace((uint8_t) buffer->value[buffer->length - 1])) {
+        buffer->length--;
+    }
+}
+
 /**
  * Free the memory associated with the buffer.
  */
diff --git a/src/util/pm_string.c b/src/util/pm_string.c
index e67fcee0ec1..8f3ef92c9b3 100644
--- a/src/util/pm_string.c
+++ b/src/util/pm_string.c
@@ -168,6 +168,26 @@ pm_string_ensure_owned(pm_string_t *string) {
     memcpy((void *) string->source, source, length);
 }
 
+/**
+ * Compare the underlying lengths and bytes of two strings. Returns 0 if the
+ * strings are equal, a negative number if the left string is less than the
+ * right string, and a positive number if the left string is greater than the
+ * right string.
+ */
+int
+pm_string_compare(const pm_string_t *left, const pm_string_t *right) {
+    size_t left_length = pm_string_length(left);
+    size_t right_length = pm_string_length(right);
+
+    if (left_length < right_length) {
+        return -1;
+    } else if (left_length > right_length) {
+        return 1;
+    }
+
+    return memcmp(pm_string_source(left), pm_string_source(right), left_length);
+}
+
 /**
  * Returns the length associated with the string.
  */
diff --git a/templates/src/node.c.erb b/templates/src/node.c.erb
index 0552767f4df..a7135d598e0 100644
--- a/templates/src/node.c.erb
+++ b/templates/src/node.c.erb
@@ -160,3 +160,45 @@ pm_node_type_to_str(pm_node_type_t node_type)
     }
     return "";
 }
+
+/**
+ * Visit each of the nodes in this subtree using the given visitor callback.
+ */
+PRISM_EXPORTED_FUNCTION void
+pm_node_visit(const pm_node_t *node, bool (*visitor)(const pm_node_t *node, void *data), void *data) {
+    if (!visitor(node, data)) return;
+
+    switch (PM_NODE_TYPE(node)) {
+        <%- nodes.each do |node| -%>
+        <%- if (fields = node.fields.select { |field| field.is_a?(Prism::NodeField) || field.is_a?(Prism::OptionalNodeField) || field.is_a?(Prism::NodeListField) }).any? -%>
+        case <%= node.type %>: {
+            const pm_<%= node.human %>_t *cast = (const pm_<%= node.human %>_t *) node;
+            <%- fields.each do |field| -%>
+
+            // Visit the <%= field.name %> field
+            <%- case field -%>
+            <%- when Prism::NodeField -%>
+            pm_node_visit((const pm_node_t *) cast-><%= field.name %>, visitor, data);
+            <%- when Prism::OptionalNodeField -%>
+            if (cast-><%= field.name %> != NULL) {
+                pm_node_visit((const pm_node_t *) cast-><%= field.name %>, visitor, data);
+            }
+            <%- when Prism::NodeListField -%>
+            const pm_node_list_t *<%= field.name %> = &cast-><%= field.name %>;
+            for (size_t index = 0; index < <%= field.name %>->size; index++) {
+                pm_node_visit(<%= field.name %>->nodes[index], visitor, data);
+            }
+            <%- end -%>
+            <%- end -%>
+
+            break;
+        }
+        <%- else -%>
+        case <%= node.type %>:
+            break;
+        <%- end -%>
+        <%- end -%>
+        case PM_SCOPE_NODE:
+            break;
+    }
+}