11 files changed, 546 insertions, 221 deletions
diff --git a/prism/prism.c b/prism/prism.c
index f90086031d..4adc66ef7c 100644
--- a/prism/prism.c
+++ b/prism/prism.c
@@ -4240,7 +4240,7 @@ pm_regular_expression_node_create_unescaped(pm_parser_t *parser, const pm_token_
 // Allocate a new initialize a new RegularExpressionNode node.
 static inline pm_regular_expression_node_t *
 pm_regular_expression_node_create(pm_parser_t *parser, const pm_token_t *opening, const pm_token_t *content, const pm_token_t *closing) {
-    return pm_regular_expression_node_create_unescaped(parser, opening, content, closing, &PM_EMPTY_STRING);
+    return pm_regular_expression_node_create_unescaped(parser, opening, content, closing, &PM_STRING_EMPTY);
 }
 
 // Allocate a new RequiredParameterNode node.
@@ -4588,7 +4588,7 @@ pm_string_node_create_unescaped(pm_parser_t *parser, const pm_token_t *opening,
 // Allocate a new StringNode node.
 static pm_string_node_t *
 pm_string_node_create(pm_parser_t *parser, const pm_token_t *opening, const pm_token_t *content, const pm_token_t *closing) {
-    return pm_string_node_create_unescaped(parser, opening, content, closing, &PM_EMPTY_STRING);
+    return pm_string_node_create_unescaped(parser, opening, content, closing, &PM_STRING_EMPTY);
 }
 
 // Allocate a new StringNode node and create it using the current string on the
@@ -4596,7 +4596,7 @@ pm_string_node_create(pm_parser_t *parser, const pm_token_t *opening, const pm_t
 static pm_string_node_t *
 pm_string_node_create_current_string(pm_parser_t *parser, const pm_token_t *opening, const pm_token_t *content, const pm_token_t *closing) {
     pm_string_node_t *node = pm_string_node_create_unescaped(parser, opening, content, closing, &parser->current_string);
-    parser->current_string = PM_EMPTY_STRING;
+    parser->current_string = PM_STRING_EMPTY;
     return node;
 }
 
@@ -4663,14 +4663,14 @@ pm_symbol_node_create_unescaped(pm_parser_t *parser, const pm_token_t *opening,
 // Allocate and initialize a new SymbolNode node.
 static inline pm_symbol_node_t *
 pm_symbol_node_create(pm_parser_t *parser, const pm_token_t *opening, const pm_token_t *value, const pm_token_t *closing) {
-    return pm_symbol_node_create_unescaped(parser, opening, value, closing, &PM_EMPTY_STRING);
+    return pm_symbol_node_create_unescaped(parser, opening, value, closing, &PM_STRING_EMPTY);
 }
 
 // Allocate and initialize a new SymbolNode node with the current string.
 static pm_symbol_node_t *
 pm_symbol_node_create_current_string(pm_parser_t *parser, const pm_token_t *opening, const pm_token_t *value, const pm_token_t *closing) {
     pm_symbol_node_t *node = pm_symbol_node_create_unescaped(parser, opening, value, closing, &parser->current_string);
-    parser->current_string = PM_EMPTY_STRING;
+    parser->current_string = PM_STRING_EMPTY;
     return node;
 }
 
@@ -5047,7 +5047,7 @@ pm_xstring_node_create_unescaped(pm_parser_t *parser, const pm_token_t *opening,
 // Allocate and initialize a new XStringNode node.
 static inline pm_x_string_node_t *
 pm_xstring_node_create(pm_parser_t *parser, const pm_token_t *opening, const pm_token_t *content, const pm_token_t *closing) {
-    return pm_xstring_node_create_unescaped(parser, opening, content, closing, &PM_EMPTY_STRING);
+    return pm_xstring_node_create_unescaped(parser, opening, content, closing, &PM_STRING_EMPTY);
 }
 
 // Allocate a new YieldNode node.
@@ -12428,7 +12428,7 @@ parse_strings(pm_parser_t *parser) {
             // start with a single string content node.
             pm_string_t unescaped;
             if (match1(parser, PM_TOKEN_EOF)) {
-                unescaped = PM_EMPTY_STRING;
+                unescaped = PM_STRING_EMPTY;
             } else {
                 unescaped = parser->current_string;
             }
@@ -12996,9 +12996,9 @@ parse_expression_prefix(pm_parser_t *parser, pm_binding_power_t binding_power) {
                 pm_token_t content = parse_strings_empty_content(parser->previous.start);
 
                 if (quote == PM_HEREDOC_QUOTE_BACKTICK) {
-                    node = (pm_node_t *) pm_xstring_node_create_unescaped(parser, &opening, &content, &parser->previous, &PM_EMPTY_STRING);
+                    node = (pm_node_t *) pm_xstring_node_create_unescaped(parser, &opening, &content, &parser->previous, &PM_STRING_EMPTY);
                 } else {
-                    node = (pm_node_t *) pm_string_node_create_unescaped(parser, &opening, &content, &parser->previous, &PM_EMPTY_STRING);
+                    node = (pm_node_t *) pm_string_node_create_unescaped(parser, &opening, &content, &parser->previous, &PM_STRING_EMPTY);
                 }
 
                 node->location.end = opening.end;
@@ -15706,7 +15706,7 @@ pm_parser_init(pm_parser_t *parser, const uint8_t *source, size_t size, const ch
         .constant_pool = PM_CONSTANT_POOL_EMPTY,
         .newline_list = PM_NEWLINE_LIST_EMPTY,
         .integer_base = 0,
-        .current_string = PM_EMPTY_STRING,
+        .current_string = PM_STRING_EMPTY,
         .command_start = true,
         .recovering = false,
         .encoding_changed = false,
@@ -15886,7 +15886,7 @@ pm_parse_serialize_comments(const uint8_t *source, size_t size, pm_buffer_t *buf
 #undef PM_CASE_KEYWORD
 #undef PM_CASE_OPERATOR
 #undef PM_CASE_WRITABLE
-#undef PM_EMPTY_STRING
+#undef PM_STRING_EMPTY
 #undef PM_LOCATION_NODE_BASE_VALUE
 #undef PM_LOCATION_NODE_VALUE
 #undef PM_LOCATION_NULL_VALUE
diff --git a/prism/util/pm_buffer.c b/prism/util/pm_buffer.c
index db2415a807..acc6cad725 100644
--- a/prism/util/pm_buffer.c
+++ b/prism/util/pm_buffer.c
@@ -1,12 +1,16 @@
 #include "prism/util/pm_buffer.h"
 
-// Return the size of the pm_buffer_t struct.
+/**
+ * Return the size of the pm_buffer_t struct.
+ */
 size_t
 pm_buffer_sizeof(void) {
     return sizeof(pm_buffer_t);
 }
 
-// Initialize a pm_buffer_t with the given capacity.
+/**
+ * Initialize a pm_buffer_t with the given capacity.
+ */
 bool
 pm_buffer_init_capacity(pm_buffer_t *buffer, size_t capacity) {
     buffer->length = 0;
@@ -16,25 +20,33 @@ pm_buffer_init_capacity(pm_buffer_t *buffer, size_t capacity) {
     return buffer->value != NULL;
 }
 
-// Initialize a pm_buffer_t with its default values.
+/**
+ * Initialize a pm_buffer_t with its default values.
+ */
 bool
 pm_buffer_init(pm_buffer_t *buffer) {
     return pm_buffer_init_capacity(buffer, 1024);
 }
 
-// Return the value of the buffer.
+/**
+ * Return the value of the buffer.
+ */
 char *
 pm_buffer_value(pm_buffer_t *buffer) {
     return buffer->value;
 }
 
-// Return the length of the buffer.
+/**
+ * Return the length of the buffer.
+ */
 size_t
 pm_buffer_length(pm_buffer_t *buffer) {
     return buffer->length;
 }
 
-// Append the given amount of space to the buffer.
+/**
+ * Append the given amount of space to the buffer.
+ */
 static inline void
 pm_buffer_append_length(pm_buffer_t *buffer, size_t length) {
     size_t next_length = buffer->length + length;
@@ -54,7 +66,9 @@ pm_buffer_append_length(pm_buffer_t *buffer, size_t length) {
     buffer->length = next_length;
 }
 
-// Append a generic pointer to memory to the buffer.
+/**
+ * Append a generic pointer to memory to the buffer.
+ */
 static inline void
 pm_buffer_append(pm_buffer_t *buffer, const void *source, size_t length) {
     size_t cursor = buffer->length;
@@ -62,7 +76,9 @@ pm_buffer_append(pm_buffer_t *buffer, const void *source, size_t length) {
     memcpy(buffer->value + cursor, source, length);
 }
 
-// Append the given amount of space as zeroes to the buffer.
+/**
+ * Append the given amount of space as zeroes to the buffer.
+ */
 void
 pm_buffer_append_zeroes(pm_buffer_t *buffer, size_t length) {
     size_t cursor = buffer->length;
@@ -70,7 +86,9 @@ pm_buffer_append_zeroes(pm_buffer_t *buffer, size_t length) {
     memset(buffer->value + cursor, 0, length);
 }
 
-// Append a formatted string to the buffer.
+/**
+ * Append a formatted string to the buffer.
+ */
 void
 pm_buffer_append_format(pm_buffer_t *buffer, const char *format, ...) {
     va_list arguments;
@@ -91,26 +109,34 @@ pm_buffer_append_format(pm_buffer_t *buffer, const char *format, ...) {
     buffer->length--;
 }
 
-// Append a string to the buffer.
+/**
+ * Append a string to the buffer.
+ */
 void
 pm_buffer_append_string(pm_buffer_t *buffer, const char *value, size_t length) {
     pm_buffer_append(buffer, value, length);
 }
 
-// Append a list of bytes to the buffer.
+/**
+ * Append a list of bytes to the buffer.
+ */
 void
 pm_buffer_append_bytes(pm_buffer_t *buffer, const uint8_t *value, size_t length) {
     pm_buffer_append(buffer, (const char *) value, length);
 }
 
-// Append a single byte to the buffer.
+/**
+ * Append a single byte to the buffer.
+ */
 void
 pm_buffer_append_byte(pm_buffer_t *buffer, uint8_t value) {
     const void *source = &value;
     pm_buffer_append(buffer, source, sizeof(uint8_t));
 }
 
-// Append a 32-bit unsigned integer to the buffer as a variable-length integer.
+/**
+ * Append a 32-bit unsigned integer to the buffer as a variable-length integer.
+ */
 void
 pm_buffer_append_varint(pm_buffer_t *buffer, uint32_t value) {
     if (value < 128) {
@@ -125,7 +151,9 @@ pm_buffer_append_varint(pm_buffer_t *buffer, uint32_t value) {
     }
 }
 
-// Concatenate one buffer onto another.
+/**
+ * Concatenate one buffer onto another.
+ */
 void
 pm_buffer_concat(pm_buffer_t *destination, const pm_buffer_t *source) {
     if (source->length > 0) {
@@ -133,7 +161,9 @@ pm_buffer_concat(pm_buffer_t *destination, const pm_buffer_t *source) {
     }
 }
 
-// Free the internal memory associated with the buffer.
+/**
+ * Free the memory associated with the buffer.
+ */
 void
 pm_buffer_free(pm_buffer_t *buffer) {
     free(buffer->value);
diff --git a/prism/util/pm_buffer.h b/prism/util/pm_buffer.h
index 69edb1525a..a2bccb3d00 100644
--- a/prism/util/pm_buffer.h
+++ b/prism/util/pm_buffer.h
@@ -9,52 +9,125 @@
 #include <stdlib.h>
 #include <string.h>
 
-// A pm_buffer_t is a simple memory buffer that stores data in a contiguous
-// block of memory. It is used to store the serialized representation of a
-// prism tree.
+/**
+ * A pm_buffer_t is a simple memory buffer that stores data in a contiguous
+ * block of memory.
+ */
 typedef struct {
+    /** The length of the buffer in bytes. */
     size_t length;
+
+    /** The capacity of the buffer in bytes that has been allocated. */
     size_t capacity;
+
+    /** A pointer to the start of the buffer. */
     char *value;
 } pm_buffer_t;
 
-// Return the size of the pm_buffer_t struct.
+/**
+ * Return the size of the pm_buffer_t struct.
+ *
+ * @returns The size of the pm_buffer_t struct.
+ */
 PRISM_EXPORTED_FUNCTION size_t pm_buffer_sizeof(void);
 
-// Initialize a pm_buffer_t with the given capacity.
+/**
+ * Initialize a pm_buffer_t with the given capacity.
+ *
+ * @param buffer The buffer to initialize.
+ * @param capacity The capacity of the buffer.
+ * @returns True if the buffer was initialized successfully, false otherwise.
+ */
 bool pm_buffer_init_capacity(pm_buffer_t *buffer, size_t capacity);
 
-// Initialize a pm_buffer_t with its default values.
+/**
+ * Initialize a pm_buffer_t with its default values.
+ *
+ * @param buffer The buffer to initialize.
+ * @returns True if the buffer was initialized successfully, false otherwise.
+ */
 PRISM_EXPORTED_FUNCTION bool pm_buffer_init(pm_buffer_t *buffer);
 
-// Return the value of the buffer.
+/**
+ * Return the value of the 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);
 
-// Return the length of the buffer.
+/**
+ * Return the length of the 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);
 
-// Append the given amount of space as zeroes to the buffer.
+/**
+ * Append the given amount of space as zeroes to the buffer.
+ *
+ * @param buffer The buffer to append to.
+ * @param length The amount of space to append and zero.
+ */
 void pm_buffer_append_zeroes(pm_buffer_t *buffer, size_t length);
 
-// Append a formatted string to the buffer.
+/**
+ * Append a formatted string to the buffer.
+ *
+ * @param buffer The buffer to append to.
+ * @param format The format string to append.
+ * @param ... The arguments to the format string.
+ */
 void pm_buffer_append_format(pm_buffer_t *buffer, const char *format, ...) PRISM_ATTRIBUTE_FORMAT(2, 3);
 
-// Append a string to the buffer.
+/**
+ * Append a string to the buffer.
+ *
+ * @param buffer The buffer to append to.
+ * @param value The string to append.
+ * @param length The length of the string to append.
+ */
 void pm_buffer_append_string(pm_buffer_t *buffer, const char *value, size_t length);
 
-// Append a list of bytes to the buffer.
+/**
+ * Append a list of bytes to the buffer.
+ *
+ * @param buffer The buffer to append to.
+ * @param value The bytes to append.
+ * @param length The length of the bytes to append.
+ */
 void pm_buffer_append_bytes(pm_buffer_t *buffer, const uint8_t *value, size_t length);
 
-// Append a single byte to the buffer.
+/**
+ * Append a single byte to the buffer.
+ *
+ * @param buffer The buffer to append to.
+ * @param value The byte to append.
+ */
 void pm_buffer_append_byte(pm_buffer_t *buffer, uint8_t value);
 
-// Append a 32-bit unsigned integer to the buffer.
+/**
+ * Append a 32-bit unsigned integer to the buffer as a variable-length integer.
+ *
+ * @param buffer The buffer to append to.
+ * @param value The integer to append.
+ */
 void pm_buffer_append_varint(pm_buffer_t *buffer, uint32_t value);
 
-// Append one buffer onto another.
+/**
+ * Concatenate one buffer onto another.
+ *
+ * @param destination The buffer to concatenate onto.
+ * @param source The buffer to concatenate.
+ */
 void pm_buffer_concat(pm_buffer_t *destination, const pm_buffer_t *source);
 
-// Free the memory associated with the buffer.
+/**
+ * Free the memory associated with the buffer.
+ *
+ * @param buffer The buffer to free.
+ */
 PRISM_EXPORTED_FUNCTION void pm_buffer_free(pm_buffer_t *buffer);
 
 #endif
diff --git a/prism/util/pm_char.c b/prism/util/pm_char.c
index 59a188ae0a..13eddbba48 100644
--- a/prism/util/pm_char.c
+++ b/prism/util/pm_char.c
@@ -53,6 +53,10 @@ static const uint8_t pm_number_table[256] = {
     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // Fx
 };
 
+/**
+ * Returns the number of characters at the start of the string that match the
+ * given kind. Disallows searching past the given maximum number of characters.
+ */
 static inline size_t
 pm_strspn_char_kind(const uint8_t *string, ptrdiff_t length, uint8_t kind) {
     if (length <= 0) return 0;
@@ -64,16 +68,20 @@ pm_strspn_char_kind(const uint8_t *string, ptrdiff_t length, uint8_t kind) {
     return size;
 }
 
-// Returns the number of characters at the start of the string that are
-// whitespace. Disallows searching past the given maximum number of characters.
+/**
+ * Returns the number of characters at the start of the string that are
+ * whitespace. Disallows searching past the given maximum number of characters.
+ */
 size_t
 pm_strspn_whitespace(const uint8_t *string, ptrdiff_t length) {
     return pm_strspn_char_kind(string, length, PRISM_CHAR_BIT_WHITESPACE);
 }
 
-// Returns the number of characters at the start of the string that are
-// whitespace while also tracking the location of each newline. Disallows
-// searching past the given maximum number of characters.
+/**
+ * Returns the number of characters at the start of the string that are
+ * whitespace while also tracking the location of each newline. Disallows
+ * searching past the given maximum number of characters.
+ */
 size_t
 pm_strspn_whitespace_newlines(const uint8_t *string, ptrdiff_t length, pm_newline_list_t *newline_list) {
     if (length <= 0) return 0;
@@ -92,40 +100,53 @@ pm_strspn_whitespace_newlines(const uint8_t *string, ptrdiff_t length, pm_newlin
     return size;
 }
 
-// Returns the number of characters at the start of the string that are inline
-// whitespace. Disallows searching past the given maximum number of characters.
+/**
+ * Returns the number of characters at the start of the string that are inline
+ * whitespace. Disallows searching past the given maximum number of characters.
+ */
 size_t
 pm_strspn_inline_whitespace(const uint8_t *string, ptrdiff_t length) {
     return pm_strspn_char_kind(string, length, PRISM_CHAR_BIT_INLINE_WHITESPACE);
 }
 
-// Returns the number of characters at the start of the string that are regexp
-// options. Disallows searching past the given maximum number of characters.
+/**
+ * Returns the number of characters at the start of the string that are regexp
+ * options. Disallows searching past the given maximum number of characters.
+ */
 size_t
 pm_strspn_regexp_option(const uint8_t *string, ptrdiff_t length) {
     return pm_strspn_char_kind(string, length, PRISM_CHAR_BIT_REGEXP_OPTION);
 }
 
+/**
+ * Returns true if the given character matches the given kind.
+ */
 static inline bool
 pm_char_is_char_kind(const uint8_t b, uint8_t kind) {
     return (pm_byte_table[b] & kind) != 0;
 }
 
-// Returns true if the given character is a whitespace character.
+/**
+ * Returns true if the given character is a whitespace character.
+ */
 bool
 pm_char_is_whitespace(const uint8_t b) {
     return pm_char_is_char_kind(b, PRISM_CHAR_BIT_WHITESPACE);
 }
 
-// Returns true if the given character is an inline whitespace character.
+/**
+ * Returns true if the given character is an inline whitespace character.
+ */
 bool
 pm_char_is_inline_whitespace(const uint8_t b) {
     return pm_char_is_char_kind(b, PRISM_CHAR_BIT_INLINE_WHITESPACE);
 }
 
-// Scan through the string and return the number of characters at the start of
-// the string that match the given kind. Disallows searching past the given
-// maximum number of characters.
+/**
+ * Scan through the string and return the number of characters at the start of
+ * the string that match the given kind. Disallows searching past the given
+ * maximum number of characters.
+ */
 static inline size_t
 pm_strspn_number_kind(const uint8_t *string, ptrdiff_t length, uint8_t kind) {
     if (length <= 0) return 0;
@@ -137,12 +158,14 @@ pm_strspn_number_kind(const uint8_t *string, ptrdiff_t length, uint8_t kind) {
     return size;
 }
 
-// Scan through the string and return the number of characters at the start of
-// the string that match the given kind. Disallows searching past the given
-// maximum number of characters.
-//
-// Additionally, report the location of the last invalid underscore character
-// found in the string through the out invalid parameter.
+/**
+ * Scan through the string and return the number of characters at the start of
+ * the string that match the given kind. Disallows searching past the given
+ * maximum number of characters.
+ *
+ * Additionally, report the location of the last invalid underscore character
+ * found in the string through the out invalid parameter.
+ */
 static inline size_t
 pm_strspn_number_kind_underscores(const uint8_t *string, ptrdiff_t length, const uint8_t **invalid, uint8_t kind) {
     if (length <= 0) return 0;
@@ -166,93 +189,116 @@ pm_strspn_number_kind_underscores(const uint8_t *string, ptrdiff_t length, const
     return size;
 }
 
-// Returns the number of characters at the start of the string that are binary
-// digits or underscores. Disallows searching past the given maximum number of
-// characters.
-//
-// If multiple underscores are found in a row or if an underscore is
-// found at the end of the number, then the invalid pointer is set to the index
-// of the first invalid underscore.
+/**
+ * Returns the number of characters at the start of the string that are binary
+ * digits or underscores. Disallows searching past the given maximum number of
+ * characters.
+ *
+ * If multiple underscores are found in a row or if an underscore is
+ * found at the end of the number, then the invalid pointer is set to the index
+ * of the first invalid underscore.
+ */
 size_t
 pm_strspn_binary_number(const uint8_t *string, ptrdiff_t length, const uint8_t **invalid) {
     return pm_strspn_number_kind_underscores(string, length, invalid, PRISM_NUMBER_BIT_BINARY_NUMBER);
 }
 
-// Returns the number of characters at the start of the string that are octal
-// digits or underscores. Disallows searching past the given maximum number of
-// characters.
-//
-// If multiple underscores are found in a row or if an underscore is
-// found at the end of the number, then the invalid pointer is set to the index
-// of the first invalid underscore.
+/**
+ * Returns the number of characters at the start of the string that are octal
+ * digits or underscores. Disallows searching past the given maximum number of
+ * characters.
+ *
+ * If multiple underscores are found in a row or if an underscore is
+ * found at the end of the number, then the invalid pointer is set to the index
+ * of the first invalid underscore.
+ */
 size_t
 pm_strspn_octal_number(const uint8_t *string, ptrdiff_t length, const uint8_t **invalid) {
     return pm_strspn_number_kind_underscores(string, length, invalid, PRISM_NUMBER_BIT_OCTAL_NUMBER);
 }
 
-// Returns the number of characters at the start of the string that are decimal
-// digits. Disallows searching past the given maximum number of characters.
+/**
+ * Returns the number of characters at the start of the string that are decimal
+ * digits. Disallows searching past the given maximum number of characters.
+ */
 size_t
 pm_strspn_decimal_digit(const uint8_t *string, ptrdiff_t length) {
     return pm_strspn_number_kind(string, length, PRISM_NUMBER_BIT_DECIMAL_DIGIT);
 }
 
-// Returns the number of characters at the start of the string that are decimal
-// digits or underscores. Disallows searching past the given maximum number of
-// characters.
-//
-// If multiple underscores are found in a row or if an underscore is
-// found at the end of the number, then the invalid pointer is set to the index
-// of the first invalid underscore.
+/**
+ * Returns the number of characters at the start of the string that are decimal
+ * digits or underscores. Disallows searching past the given maximum number of
+ * characters.
+ *
+ * If multiple underscores are found in a row or if an underscore is
+ * found at the end of the number, then the invalid pointer is set to the index
+ * of the first invalid underscore
+ */
 size_t
 pm_strspn_decimal_number(const uint8_t *string, ptrdiff_t length, const uint8_t **invalid) {
     return pm_strspn_number_kind_underscores(string, length, invalid, PRISM_NUMBER_BIT_DECIMAL_NUMBER);
 }
 
-// Returns the number of characters at the start of the string that are
-// hexadecimal digits. Disallows searching past the given maximum number of
-// characters.
+/**
+ * Returns the number of characters at the start of the string that are
+ * hexadecimal digits. Disallows searching past the given maximum number of
+ * characters.
+ */
 size_t
 pm_strspn_hexadecimal_digit(const uint8_t *string, ptrdiff_t length) {
     return pm_strspn_number_kind(string, length, PRISM_NUMBER_BIT_HEXADECIMAL_DIGIT);
 }
 
-// Returns the number of characters at the start of the string that are
-// hexadecimal digits or underscores. Disallows searching past the given maximum
-// number of characters.
-//
-// If multiple underscores are found in a row or if an underscore is
-// found at the end of the number, then the invalid pointer is set to the index
-// of the first invalid underscore.
+/**
+ * Returns the number of characters at the start of the string that are
+ * hexadecimal digits or underscores. Disallows searching past the given maximum
+ * number of characters.
+ *
+ * If multiple underscores are found in a row or if an underscore is
+ * found at the end of the number, then the invalid pointer is set to the index
+ * of the first invalid underscore.
+ */
 size_t
 pm_strspn_hexadecimal_number(const uint8_t *string, ptrdiff_t length, const uint8_t **invalid) {
     return pm_strspn_number_kind_underscores(string, length, invalid, PRISM_NUMBER_BIT_HEXADECIMAL_NUMBER);
 }
 
+/**
+ * Returns true if the given character matches the given kind.
+ */
 static inline bool
 pm_char_is_number_kind(const uint8_t b, uint8_t kind) {
     return (pm_number_table[b] & kind) != 0;
 }
 
-// Returns true if the given character is a binary digit.
+/**
+ * Returns true if the given character is a binary digit.
+ */
 bool
 pm_char_is_binary_digit(const uint8_t b) {
     return pm_char_is_number_kind(b, PRISM_NUMBER_BIT_BINARY_DIGIT);
 }
 
-// Returns true if the given character is an octal digit.
+/**
+ * Returns true if the given character is an octal digit.
+ */
 bool
 pm_char_is_octal_digit(const uint8_t b) {
     return pm_char_is_number_kind(b, PRISM_NUMBER_BIT_OCTAL_DIGIT);
 }
 
-// Returns true if the given character is a decimal digit.
+/**
+ * Returns true if the given character is a decimal digit.
+ */
 bool
 pm_char_is_decimal_digit(const uint8_t b) {
     return pm_char_is_number_kind(b, PRISM_NUMBER_BIT_DECIMAL_DIGIT);
 }
 
-// Returns true if the given character is a hexadecimal digit.
+/**
+ * Returns true if the given character is a hexadecimal digit.
+ */
 bool
 pm_char_is_hexadecimal_digit(const uint8_t b) {
     return pm_char_is_number_kind(b, PRISM_NUMBER_BIT_HEXADECIMAL_DIGIT);
diff --git a/prism/util/pm_char.h b/prism/util/pm_char.h
index f7f195eecc..2bdc67de4a 100644
--- a/prism/util/pm_char.h
+++ b/prism/util/pm_char.h
@@ -7,85 +7,194 @@
 #include <stdbool.h>
 #include <stddef.h>
 
-// Returns the number of characters at the start of the string that are
-// whitespace. Disallows searching past the given maximum number of characters.
+/**
+ * Returns the number of characters at the start of the string that are
+ * whitespace. Disallows searching past the given maximum number of characters.
+ *
+ * @param string The string to search.
+ * @param length The maximum number of characters to search.
+ * @return The number of characters at the start of the string that are
+ *     whitespace.
+ */
 size_t pm_strspn_whitespace(const uint8_t *string, ptrdiff_t length);
 
-// Returns the number of characters at the start of the string that are
-// whitespace while also tracking the location of each newline. Disallows
-// searching past the given maximum number of characters.
+/**
+ * Returns the number of characters at the start of the string that are
+ * whitespace while also tracking the location of each newline. Disallows
+ * searching past the given maximum number of characters.
+ *
+ * @param string The string to search.
+ * @param length The maximum number of characters to search.
+ * @param newline_list The list of newlines to populate.
+ * @return The number of characters at the start of the string that are
+ *     whitespace.
+ */
 size_t
 pm_strspn_whitespace_newlines(const uint8_t *string, ptrdiff_t length, pm_newline_list_t *newline_list);
 
-// Returns the number of characters at the start of the string that are inline
-// whitespace. Disallows searching past the given maximum number of characters.
+/**
+ * Returns the number of characters at the start of the string that are inline
+ * whitespace. Disallows searching past the given maximum number of characters.
+ *
+ * @param string The string to search.
+ * @param length The maximum number of characters to search.
+ * @return The number of characters at the start of the string that are inline
+ *     whitespace.
+ */
 size_t pm_strspn_inline_whitespace(const uint8_t *string, ptrdiff_t length);
 
-// Returns the number of characters at the start of the string that are decimal
-// digits. Disallows searching past the given maximum number of characters.
+/**
+ * Returns the number of characters at the start of the string that are decimal
+ * digits. Disallows searching past the given maximum number of characters.
+ *
+ * @param string The string to search.
+ * @param length The maximum number of characters to search.
+ * @return The number of characters at the start of the string that are decimal
+ *     digits.
+ */
 size_t pm_strspn_decimal_digit(const uint8_t *string, ptrdiff_t length);
 
-// Returns the number of characters at the start of the string that are
-// hexadecimal digits. Disallows searching past the given maximum number of
-// characters.
+/**
+ * Returns the number of characters at the start of the string that are
+ * hexadecimal digits. Disallows searching past the given maximum number of
+ * characters.
+ *
+ * @param string The string to search.
+ * @param length The maximum number of characters to search.
+ * @return The number of characters at the start of the string that are
+ *     hexadecimal digits.
+ */
 size_t pm_strspn_hexadecimal_digit(const uint8_t *string, ptrdiff_t length);
 
-// Returns the number of characters at the start of the string that are octal
-// digits or underscores. Disallows searching past the given maximum number of
-// characters.
-//
-// If multiple underscores are found in a row or if an underscore is
-// found at the end of the number, then the invalid pointer is set to the index
-// of the first invalid underscore.
+/**
+ * Returns the number of characters at the start of the string that are octal
+ * digits or underscores. Disallows searching past the given maximum number of
+ * characters.
+ *
+ * If multiple underscores are found in a row or if an underscore is
+ * found at the end of the number, then the invalid pointer is set to the index
+ * of the first invalid underscore.
+ *
+ * @param string The string to search.
+ * @param length The maximum number of characters to search.
+ * @param invalid The pointer to set to the index of the first invalid
+ *     underscore.
+ * @return The number of characters at the start of the string that are octal
+ *     digits or underscores.
+ */
 size_t pm_strspn_octal_number(const uint8_t *string, ptrdiff_t length, const uint8_t **invalid);
 
-// Returns the number of characters at the start of the string that are decimal
-// digits or underscores. Disallows searching past the given maximum number of
-// characters.
-//
-// If multiple underscores are found in a row or if an underscore is
-// found at the end of the number, then the invalid pointer is set to the index
-// of the first invalid underscore.
+/**
+ * Returns the number of characters at the start of the string that are decimal
+ * digits or underscores. Disallows searching past the given maximum number of
+ * characters.
+ *
+ * If multiple underscores are found in a row or if an underscore is
+ * found at the end of the number, then the invalid pointer is set to the index
+ * of the first invalid underscore.
+ *
+ * @param string The string to search.
+ * @param length The maximum number of characters to search.
+ * @param invalid The pointer to set to the index of the first invalid
+ *     underscore.
+ * @return The number of characters at the start of the string that are decimal
+ *     digits or underscores.
+ */
 size_t pm_strspn_decimal_number(const uint8_t *string, ptrdiff_t length, const uint8_t **invalid);
 
-// Returns the number of characters at the start of the string that are
-// hexadecimal digits or underscores. Disallows searching past the given maximum
-// number of characters.
-//
-// If multiple underscores are found in a row or if an underscore is
-// found at the end of the number, then the invalid pointer is set to the index
-// of the first invalid underscore.
+/**
+ * Returns the number of characters at the start of the string that are
+ * hexadecimal digits or underscores. Disallows searching past the given maximum
+ * number of characters.
+ *
+ * If multiple underscores are found in a row or if an underscore is
+ * found at the end of the number, then the invalid pointer is set to the index
+ * of the first invalid underscore.
+ *
+ * @param string The string to search.
+ * @param length The maximum number of characters to search.
+ * @param invalid The pointer to set to the index of the first invalid
+ *     underscore.
+ * @return The number of characters at the start of the string that are
+ *     hexadecimal digits or underscores.
+ */
 size_t pm_strspn_hexadecimal_number(const uint8_t *string, ptrdiff_t length, const uint8_t **invalid);
 
-// Returns the number of characters at the start of the string that are regexp
-// options. Disallows searching past the given maximum number of characters.
+/**
+ * Returns the number of characters at the start of the string that are regexp
+ * options. Disallows searching past the given maximum number of characters.
+ *
+ * @param string The string to search.
+ * @param length The maximum number of characters to search.
+ * @return The number of characters at the start of the string that are regexp
+ *     options.
+ */
 size_t pm_strspn_regexp_option(const uint8_t *string, ptrdiff_t length);
 
-// Returns the number of characters at the start of the string that are binary
-// digits or underscores. Disallows searching past the given maximum number of
-// characters.
-//
-// If multiple underscores are found in a row or if an underscore is
-// found at the end of the number, then the invalid pointer is set to the index
-// of the first invalid underscore.
+/**
+ * Returns the number of characters at the start of the string that are binary
+ * digits or underscores. Disallows searching past the given maximum number of
+ * characters.
+ *
+ * If multiple underscores are found in a row or if an underscore is
+ * found at the end of the number, then the invalid pointer is set to the index
+ * of the first invalid underscore.
+ *
+ * @param string The string to search.
+ * @param length The maximum number of characters to search.
+ * @param invalid The pointer to set to the index of the first invalid
+ *     underscore.
+ * @return The number of characters at the start of the string that are binary
+ *     digits or underscores.
+ */
 size_t pm_strspn_binary_number(const uint8_t *string, ptrdiff_t length, const uint8_t **invalid);
 
-// Returns true if the given character is a whitespace character.
+/**
+ * Returns true if the given character is a whitespace character.
+ *
+ * @param b The character to check.
+ * @return True if the given character is a whitespace character.
+ */
 bool pm_char_is_whitespace(const uint8_t b);
 
-// Returns true if the given character is an inline whitespace character.
+/**
+ * Returns true if the given character is an inline whitespace character.
+ *
+ * @param b The character to check.
+ * @return True if the given character is an inline whitespace character.
+ */
 bool pm_char_is_inline_whitespace(const uint8_t b);
 
-// Returns true if the given character is a binary digit.
+/**
+ * Returns true if the given character is a binary digit.
+ *
+ * @param b The character to check.
+ * @return True if the given character is a binary digit.
+ */
 bool pm_char_is_binary_digit(const uint8_t b);
 
-// Returns true if the given character is an octal digit.
+/**
+ * Returns true if the given character is an octal digit.
+ *
+ * @param b The character to check.
+ * @return True if the given character is an octal digit.
+ */
 bool pm_char_is_octal_digit(const uint8_t b);
 
-// Returns true if the given character is a decimal digit.
+/**
+ * Returns true if the given character is a decimal digit.
+ *
+ * @param b The character to check.
+ * @return True if the given character is a decimal digit.
+ */
 bool pm_char_is_decimal_digit(const uint8_t b);
 
-// Returns true if the given character is a hexadecimal digit.
+/**
+ * Returns true if the given character is a hexadecimal digit.
+ *
+ * @param b The character to check.
+ * @return True if the given character is a hexadecimal digit.
+ */
 bool pm_char_is_hexadecimal_digit(const uint8_t b);
 
 #endif
diff --git a/prism/util/pm_state_stack.c b/prism/util/pm_state_stack.c
index f7f9c245dd..2a424b4c03 100644
--- a/prism/util/pm_state_stack.c
+++ b/prism/util/pm_state_stack.c
@@ -1,18 +1,24 @@
 #include "prism/util/pm_state_stack.h"
 
-// Pushes a value onto the stack.
+/**
+ * Pushes a value onto the stack.
+ */
 void
 pm_state_stack_push(pm_state_stack_t *stack, bool value) {
     *stack = (*stack << 1) | (value & 1);
 }
 
-// Pops a value off the stack.
+/**
+ * Pops a value off the stack.
+ */
 void
 pm_state_stack_pop(pm_state_stack_t *stack) {
     *stack >>= 1;
 }
 
-// Returns the value at the top of the stack.
+/**
+ * Returns the value at the top of the stack.
+ */
 bool
 pm_state_stack_p(pm_state_stack_t *stack) {
     return *stack & 1;
diff --git a/prism/util/pm_state_stack.h b/prism/util/pm_state_stack.h
index aef639074a..268243085a 100644
--- a/prism/util/pm_state_stack.h
+++ b/prism/util/pm_state_stack.h
@@ -6,19 +6,36 @@
 #include <stdbool.h>
 #include <stdint.h>
 
-// A struct that represents a stack of bools.
+/**
+ * A struct that represents a stack of boolean values.
+ */
 typedef uint32_t pm_state_stack_t;
 
-// Initializes the state stack to an empty stack.
+/**
+ * Initializes the state stack to an empty stack.
+ */
 #define PM_STATE_STACK_EMPTY ((pm_state_stack_t) 0)
 
-// Pushes a value onto the stack.
+/**
+ * Pushes a value onto the stack.
+ *
+ * @param stack The stack to push the value onto.
+ * @param value The value to push onto the stack.
+ */
 void pm_state_stack_push(pm_state_stack_t *stack, bool value);
 
-// Pops a value off the stack.
+/**
+ * Pops a value off the stack.
+ *
+ * @param stack The stack to pop the value off of.
+ */
 void pm_state_stack_pop(pm_state_stack_t *stack);
 
-// Returns the value at the top of the stack.
+/**
+ * Returns the value at the top of the stack.
+ *
+ * @param stack The stack to get the value from.
+ */
 bool pm_state_stack_p(pm_state_stack_t *stack);
 
 #endif
diff --git a/prism/util/pm_string.c b/prism/util/pm_string.c
index 6ffedc86ba..46913be266 100644
--- a/prism/util/pm_string.c
+++ b/prism/util/pm_string.c
@@ -1,19 +1,16 @@
 #include "prism/util/pm_string.h"
 
-// The following headers are necessary to read files using demand paging.
-#ifdef _WIN32
-#include <windows.h>
-#else
-#include <fcntl.h>
-#include <sys/mman.h>
-#include <sys/stat.h>
-#include <unistd.h>
-#endif
+/**
+ * Returns the size of the pm_string_t struct. This is necessary to allocate the
+ * correct amount of memory in the FFI backend.
+ */
+PRISM_EXPORTED_FUNCTION size_t
+pm_string_sizeof(void) {
+    return sizeof(pm_string_t);
+}
 
 /**
  * Initialize a shared string that is based on initial input.
- *
- * @memberof pm_string_t
  */
 void
 pm_string_shared_init(pm_string_t *string, const uint8_t *start, const uint8_t *end) {
@@ -28,8 +25,6 @@ pm_string_shared_init(pm_string_t *string, const uint8_t *start, const uint8_t *
 
 /**
  * Initialize an owned string that is responsible for freeing allocated memory.
- *
- * @memberof pm_string_t
  */
 void
 pm_string_owned_init(pm_string_t *string, uint8_t *source, size_t length) {
@@ -42,8 +37,6 @@ pm_string_owned_init(pm_string_t *string, uint8_t *source, size_t length) {
 
 /**
  * Initialize a constant string that doesn't own its memory source.
- *
- * @memberof pm_string_t
  */
 void
 pm_string_constant_init(pm_string_t *string, const char *source, size_t length) {
@@ -64,8 +57,6 @@ pm_string_constant_init(pm_string_t *string, const char *source, size_t length)
  * for large files). This means that if we're on windows we'll use
  * `MapViewOfFile`, on POSIX systems that have access to `mmap` we'll use
  * `mmap`, and on other POSIX systems we'll use `read`.
- *
- * @memberof pm_string_t
  */
 bool
 pm_string_mapped_init(pm_string_t *string, const char *filepath) {
@@ -90,7 +81,7 @@ pm_string_mapped_init(pm_string_t *string, const char *filepath) {
     // the source to a constant empty string and return.
     if (file_size == 0) {
         CloseHandle(file);
-        *string = PM_EMPTY_STRING;
+        *string = PM_STRING_EMPTY;
         return true;
     }
 
@@ -136,7 +127,7 @@ pm_string_mapped_init(pm_string_t *string, const char *filepath) {
 
     if (size == 0) {
         close(fd);
-        *string = PM_EMPTY_STRING;
+        *string = PM_STRING_EMPTY;
         return true;
     }
 
@@ -154,8 +145,6 @@ pm_string_mapped_init(pm_string_t *string, const char *filepath) {
 
 /**
  * Returns the memory size associated with the string.
- *
- * @memberof pm_string_t
  */
 size_t
 pm_string_memsize(const pm_string_t *string) {
@@ -169,8 +158,6 @@ pm_string_memsize(const pm_string_t *string) {
 /**
  * Ensure the string is owned. If it is not, then reinitialize it as owned and
  * copy over the previous source.
- *
- * @memberof pm_string_t
  */
 void
 pm_string_ensure_owned(pm_string_t *string) {
@@ -188,8 +175,6 @@ pm_string_ensure_owned(pm_string_t *string) {
 
 /**
  * Returns the length associated with the string.
- *
- * @memberof pm_string_t
  */
 PRISM_EXPORTED_FUNCTION size_t
 pm_string_length(const pm_string_t *string) {
@@ -198,8 +183,6 @@ pm_string_length(const pm_string_t *string) {
 
 /**
  * Returns the start pointer associated with the string.
- *
- * @memberof pm_string_t
  */
 PRISM_EXPORTED_FUNCTION const uint8_t *
 pm_string_source(const pm_string_t *string) {
@@ -208,8 +191,6 @@ pm_string_source(const pm_string_t *string) {
 
 /**
  * Free the associated memory of the given string.
- *
- * @memberof pm_string_t
  */
 PRISM_EXPORTED_FUNCTION void
 pm_string_free(pm_string_t *string) {
@@ -225,12 +206,3 @@ pm_string_free(pm_string_t *string) {
 #endif
     }
 }
-
-/**
- * Returns the size of the pm_string_t struct. This is necessary to allocate the
- * correct amount of memory in the FFI backend.
- */
-PRISM_EXPORTED_FUNCTION size_t
-pm_string_sizeof(void) {
-    return sizeof(pm_string_t);
-}
diff --git a/prism/util/pm_string.h b/prism/util/pm_string.h
index 5f0fc7b046..b0b7c6bf2d 100644
--- a/prism/util/pm_string.h
+++ b/prism/util/pm_string.h
@@ -9,34 +9,80 @@
 #include <stdlib.h>
 #include <string.h>
 
-// This struct represents a string value.
+// The following headers are necessary to read files using demand paging.
+#ifdef _WIN32
+#include <windows.h>
+#else
+#include <fcntl.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#endif
+
+/**
+ * A generic string type that can have various ownership semantics.
+ */
 typedef struct {
+    /** A pointer to the start of the string. */
     const uint8_t *source;
+
+    /** The length of the string in bytes of memory. */
     size_t length;
-    // This field is not the first one, because otherwise things like .pm_string_t_field = 123/pm_constant_id_t does not warn or error
-    enum { PM_STRING_SHARED, PM_STRING_OWNED, PM_STRING_CONSTANT, PM_STRING_MAPPED } type;
+
+    /** The type of the string. This field determines how the string should be freed. */
+    enum {
+        /** This string is a constant string, and should not be freed. */
+        PM_STRING_CONSTANT,
+
+        /** This is a slice of another string, and should not be freed. */
+        PM_STRING_SHARED,
+
+        /** This string owns its memory, and should be freed using `pm_string_free`. */
+        PM_STRING_OWNED,
+
+        /** This string is a memory-mapped file, and should be freed using `pm_string_free`. */
+        PM_STRING_MAPPED
+    } type;
 } pm_string_t;
 
-#define PM_EMPTY_STRING ((pm_string_t) { .type = PM_STRING_CONSTANT, .source = NULL, .length = 0 })
+/**
+ * Returns the size of the pm_string_t struct. This is necessary to allocate the
+ * correct amount of memory in the FFI backend.
+ *
+ * @return The size of the pm_string_t struct.
+ */
+PRISM_EXPORTED_FUNCTION size_t pm_string_sizeof(void);
+
+/**
+ * Defines an empty string. This is useful for initializing a string that will
+ * be filled in later.
+ */
+#define PM_STRING_EMPTY ((pm_string_t) { .type = PM_STRING_CONSTANT, .source = NULL, .length = 0 })
 
 /**
  * Initialize a shared string that is based on initial input.
  *
- * @memberof pm_string_t
+ * @param string The string to initialize.
+ * @param start The start of the string.
+ * @param end The end of the string.
  */
 void pm_string_shared_init(pm_string_t *string, const uint8_t *start, const uint8_t *end);
 
 /**
  * Initialize an owned string that is responsible for freeing allocated memory.
  *
- * @memberof pm_string_t
+ * @param string The string to initialize.
+ * @param source The source of the string.
+ * @param length The length of the string.
  */
 void pm_string_owned_init(pm_string_t *string, uint8_t *source, size_t length);
 
 /**
  * Initialize a constant string that doesn't own its memory source.
  *
- * @memberof pm_string_t
+ * @param string The string to initialize.
+ * @param source The source of the string.
+ * @param length The length of the string.
  */
 void pm_string_constant_init(pm_string_t *string, const char *source, size_t length);
 
@@ -51,14 +97,17 @@ void pm_string_constant_init(pm_string_t *string, const char *source, size_t len
  * `MapViewOfFile`, on POSIX systems that have access to `mmap` we'll use
  * `mmap`, and on other POSIX systems we'll use `read`.
  *
- * @memberof pm_string_t
+ * @param string The string to initialize.
+ * @param filepath The filepath to read.
+ * @return Whether or not the file was successfully mapped.
  */
 PRISM_EXPORTED_FUNCTION bool pm_string_mapped_init(pm_string_t *string, const char *filepath);
 
 /**
  * Returns the memory size associated with the string.
  *
- * @memberof pm_string_t
+ * @param string The string to get the memory size of.
+ * @return The size of the memory associated with the string.
  */
 size_t pm_string_memsize(const pm_string_t *string);
 
@@ -66,35 +115,31 @@ size_t pm_string_memsize(const pm_string_t *string);
  * Ensure the string is owned. If it is not, then reinitialize it as owned and
  * copy over the previous source.
  *
- * @memberof pm_string_t
+ * @param string The string to ensure is owned.
  */
 void pm_string_ensure_owned(pm_string_t *string);
 
 /**
  * Returns the length associated with the string.
  *
- * @memberof pm_string_t
+ * @param string The string to get the length of.
+ * @return The length of the string.
  */
 PRISM_EXPORTED_FUNCTION size_t pm_string_length(const pm_string_t *string);
 
 /**
  * Returns the start pointer associated with the string.
  *
- * @memberof pm_string_t
+ * @param string The string to get the start pointer of.
+ * @return The start pointer of the string.
  */
 PRISM_EXPORTED_FUNCTION const uint8_t * pm_string_source(const pm_string_t *string);
 
 /**
  * Free the associated memory of the given string.
  *
- * @memberof pm_string_t
+ * @param string The string to free.
  */
 PRISM_EXPORTED_FUNCTION void pm_string_free(pm_string_t *string);
 
-/**
- * Returns the size of the pm_string_t struct. This is necessary to allocate the
- * correct amount of memory in the FFI backend.
- */
-PRISM_EXPORTED_FUNCTION size_t pm_string_sizeof(void);
-
-#endif // PRISM_STRING_H
+#endif
diff --git a/prism/util/pm_string_list.c b/prism/util/pm_string_list.c
index 87e63a43eb..fa7f20619f 100644
--- a/prism/util/pm_string_list.c
+++ b/prism/util/pm_string_list.c
@@ -1,14 +1,18 @@
 #include "prism/util/pm_string_list.h"
 
-// Initialize a pm_string_list_t with its default values.
+/**
+ * Initialize a pm_string_list_t with its default values.
+ */
 void
 pm_string_list_init(pm_string_list_t *string_list) {
-    string_list->strings = (pm_string_t *) malloc(sizeof(pm_string_t));
     string_list->length = 0;
     string_list->capacity = 1;
+    string_list->strings = (pm_string_t *) malloc(sizeof(pm_string_t));
 }
 
-// Append a pm_string_t to the given string list.
+/**
+ * Append a pm_string_t to the given string list.
+ */
 void
 pm_string_list_append(pm_string_list_t *string_list, pm_string_t *string) {
     if (string_list->length + 1 > string_list->capacity) {
@@ -22,7 +26,9 @@ pm_string_list_append(pm_string_list_t *string_list, pm_string_t *string) {
     string_list->strings[string_list->length++] = *string;
 }
 
-// Free the memory associated with the string list.
+/**
+ * Free the memory associated with the string list
+ */
 void
 pm_string_list_free(pm_string_list_t *string_list) {
     free(string_list->strings);
diff --git a/prism/util/pm_string_list.h b/prism/util/pm_string_list.h
index 1eec7a34da..5aa3758775 100644
--- a/prism/util/pm_string_list.h
+++ b/prism/util/pm_string_list.h
@@ -7,19 +7,40 @@
 #include <stddef.h>
 #include <stdlib.h>
 
+/**
+ * A list of strings.
+ */
 typedef struct {
-    pm_string_t *strings;
+    /** The length of the string list. */
     size_t length;
+
+    /** The capacity of the string list that has been allocated. */
     size_t capacity;
+
+    /** A pointer to the start of the string list. */
+    pm_string_t *strings;
 } pm_string_list_t;
 
-// Initialize a pm_string_list_t with its default values.
+/**
+ * Initialize a pm_string_list_t with its default values.
+ *
+ * @param string_list The string list to initialize.
+ */
 PRISM_EXPORTED_FUNCTION void pm_string_list_init(pm_string_list_t *string_list);
 
-// Append a pm_string_t to the given string list.
+/**
+ * Append a pm_string_t to the given string list.
+ *
+ * @param string_list The string list to append to.
+ * @param string The string to append.
+ */
 void pm_string_list_append(pm_string_list_t *string_list, pm_string_t *string);
 
-// Free the memory associated with the string list.
+/**
+ * Free the memory associated with the string list.
+ *
+ * @param string_list The string list to free.
+ */
 PRISM_EXPORTED_FUNCTION void pm_string_list_free(pm_string_list_t *string_list);
 
 #endif