documentation for the rest of the strings library

core/strings/ascii_set.odin

@@ -5,6 +5,7 @@ import "core:unicode/utf8"
 
 Ascii_Set :: distinct [8]u32
 
+// create an ascii set of all unique characters in the string
 ascii_set_make :: proc(chars: string) -> (as: Ascii_Set, ok: bool) #no_bounds_check {
 	for i in 0..<len(chars) {
 		c := chars[i]
@@ -17,6 +18,7 @@ ascii_set_make :: proc(chars: string) -> (as: Ascii_Set, ok: bool) #no_bounds_ch
 	return
 }
 
+// returns true when the `c` byte is contained in the `as` ascii set
 ascii_set_contains :: proc(as: Ascii_Set, c: byte) -> bool #no_bounds_check {
 	return as[c>>5] & (1<<(c&31)) != 0
 }

core/strings/builder.odin

@@ -7,40 +7,56 @@ import "core:io"
 
 Builder_Flush_Proc :: #type proc(b: ^Builder) -> (do_reset: bool)
 
+/*
+	dynamic byte buffer / string builder with helper procedures
+	the dynamic array is wrapped inside the struct to be more opaque
+	you can use `fmt.sbprint*` procedures with a `^strings.Builder` directly
+*/
 Builder :: struct {
 	buf: [dynamic]byte,
 }
 
+// return a builder, default length 0 / cap 16 are done through make
 make_builder_none :: proc(allocator := context.allocator) -> Builder {
 	return Builder{buf=make([dynamic]byte, allocator)}
 }
 
+// return a builder, with a set length `len` and cap 16 byte buffer
 make_builder_len :: proc(len: int, allocator := context.allocator) -> Builder {
 	return Builder{buf=make([dynamic]byte, len, allocator)}
 }
 
+// return a builder, with a set length `len` byte buffer and a custom `cap`
 make_builder_len_cap :: proc(len, cap: int, allocator := context.allocator) -> Builder {
 	return Builder{buf=make([dynamic]byte, len, cap, allocator)}
 }
 
+// overload simple `make_builder_*` with or without len / cap parameters
 make_builder :: proc{
 	make_builder_none,
 	make_builder_len,
 	make_builder_len_cap,
 }
 
+// initialize a builder, default length 0 / cap 16 are done through make
+// replaces the existing `buf`
 init_builder_none :: proc(b: ^Builder, allocator := context.allocator) {
 	b.buf = make([dynamic]byte, allocator)
 }
 
+// initialize a builder, with a set length `len` and cap 16 byte buffer
+// replaces the existing `buf`
 init_builder_len :: proc(b: ^Builder, len: int, allocator := context.allocator) {
 	b.buf = make([dynamic]byte, len, allocator)
 }
 
+// initialize a builder, with a set length `len` byte buffer and a custom `cap`
+// replaces the existing `buf`
 init_builder_len_cap :: proc(b: ^Builder, len, cap: int, allocator := context.allocator) {
 	b.buf = make([dynamic]byte, len, cap, allocator)
 }
 
+// overload simple `init_builder_*` with or without len / ap parameters
 init_builder :: proc{
 	init_builder_none,
 	init_builder_len,
@@ -76,30 +92,42 @@ _builder_stream_vtable := &io.Stream_VTable{
 	},
 }
 
+// return an `io.Stream` from a builder
 to_stream :: proc(b: ^Builder) -> io.Stream {
 	return io.Stream{stream_vtable=_builder_stream_vtable, stream_data=b}
 }
+
+// return an `io.Writer` from a builder
 to_writer :: proc(b: ^Builder) -> io.Writer {
 	return io.to_writer(to_stream(b))
 }
 
-
-
-
+// delete and clear the builder byte buffer content
 destroy_builder :: proc(b: ^Builder) {
 	delete(b.buf)
 	clear(&b.buf)
 }
 
+// reserve the builfer byte buffer to a specific cap, when it's higher than before
 grow_builder :: proc(b: ^Builder, cap: int) {
 	reserve(&b.buf, cap)
 }
 
+// clear the builder byte buffer content
 reset_builder :: proc(b: ^Builder) {
 	clear(&b.buf)
 }
 
-
+/*
+	create an empty builder with the same slice length as its cap
+	uses the `mem.nil_allocator` to avoid allocation and keep a fixed length
+	used in `fmt.bprint*`
+	
+	bytes: [8]byte // <-- gets filled
+	builder := strings.builder_from_slice(bytes[:])
+	strings.write_byte(&builder, 'a') -> "a"
+	strings.write_byte(&builder, 'b') -> "ab"
+*/
 builder_from_slice :: proc(backing: []byte) -> Builder {
 	s := transmute(mem.Raw_Slice)backing
 	d := mem.Raw_Dynamic_Array{
@@ -112,20 +140,36 @@ builder_from_slice :: proc(backing: []byte) -> Builder {
 		buf = transmute([dynamic]byte)d,
 	}
 }
+
+// cast the builder byte buffer to a string and return it
 to_string :: proc(b: Builder) -> string {
 	return string(b.buf[:])
 }
 
+// return the length of the builder byte buffer
 builder_len :: proc(b: Builder) -> int {
 	return len(b.buf)
 }
+
+// return the cap of the builder byte buffer
 builder_cap :: proc(b: Builder) -> int {
 	return cap(b.buf)
 }
+
+// returns the space left in the builder byte buffer to use up
 builder_space :: proc(b: Builder) -> int {
-	return max(cap(b.buf), len(b.buf), 0)
+	return cap(b.buf) - len(b.buf)
 }
 
+/*
+	appends a byte to the builder, returns the append diff
+
+	builder := strings.make_builder()
+	strings.write_byte(&builder, 'a') // 1
+	strings.write_byte(&builder, 'b') // 1
+	strings.write_byte(&builder, 'c') // 1
+	fmt.println(strings.to_string(builder)) // -> abc
+*/
 write_byte :: proc(b: ^Builder, x: byte) -> (n: int) {
 	n0 := len(b.buf)
 	append(&b.buf, x)
@@ -133,6 +177,14 @@ write_byte :: proc(b: ^Builder, x: byte) -> (n: int) {
 	return n1-n0
 }
 
+/*
+	appends a slice of bytes to the builder, returns the append diff
+
+	builder := strings.make_builder()
+	bytes := [?]byte { 'a', 'b', 'c' }
+	strings.write_bytes(&builder, bytes[:]) // 3
+	fmt.println(strings.to_string(builder)) // -> abc
+*/
 write_bytes :: proc(b: ^Builder, x: []byte) -> (n: int) {
 	n0 := len(b.buf)
 	append(&b.buf, ..x)
@@ -140,11 +192,28 @@ write_bytes :: proc(b: ^Builder, x: []byte) -> (n: int) {
 	return n1-n0
 }
 
+/*
+	appends a single rune into the builder, returns written rune size and an `io.Error`
+
+	builder := strings.make_builder()
+	strings.write_rune_builder(&builder, 'ä') // 2 None
+	strings.write_rune_builder(&builder, 'b') // 1 None
+	strings.write_rune_builder(&builder, 'c') // 1 None
+	fmt.println(strings.to_string(builder)) // -> äbc
+*/
 write_rune_builder :: proc(b: ^Builder, r: rune) -> (int, io.Error) {
 	return io.write_rune(to_writer(b), r)
 }
 
+/*
+	appends a quoted rune into the builder, returns written size
 
+	builder := strings.make_builder()
+	strings.write_string(&builder, "abc") // 3
+	strings.write_quoted_rune_builder(&builder, 'ä') // 4
+	strings.write_string(&builder, "abc") // 3
+	fmt.println(strings.to_string(builder)) // -> abc'ä'abc
+*/
 write_quoted_rune_builder :: proc(b: ^Builder, r: rune) -> (n: int) {
 	return write_quoted_rune(to_writer(b), r)
 }
@@ -155,7 +224,7 @@ _write_byte :: proc(w: io.Writer, c: byte) -> int {
 	return 1 if err == nil else 0
 }
 
-
+// writer append a quoted rune into the byte buffer, return the written size
 write_quoted_rune :: proc(w: io.Writer, r: rune) -> (n: int) {
 	quote := byte('\'')
 	n += _write_byte(w, quote)
@@ -173,50 +242,75 @@ write_quoted_rune :: proc(w: io.Writer, r: rune) -> (n: int) {
 	return
 }
 
-
+// overload for `write_string_*` variants
 write_string :: proc{
 	write_string_builder,
 	write_string_writer,
 }
 
+/*
+	appends a string to the builder, return the written byte size
+	
+	builder := strings.make_builder()
+	strings.write_string(&builder, "a") // 1
+	strings.write_string(&builder, "bc") // 2	
+	strings.write_string(&builder, "xyz") // 3
+	fmt.println(strings.to_string(builder)) // -> abcxyz
+*/
 write_string_builder :: proc(b: ^Builder, s: string) -> (n: int) {
 	return write_string_writer(to_writer(b), s)
 }
 
+// appends a string to the writer
 write_string_writer :: proc(w: io.Writer, s: string) -> (n: int) {
 	n, _ = io.write(w, transmute([]byte)s)
 	return
 }
 
-
-
-
+// pops and returns the last byte in the builder
+// returns 0 when the builder is empty
 pop_byte :: proc(b: ^Builder) -> (r: byte) {
 	if len(b.buf) == 0 {
 		return 0
 	}
+
 	r = b.buf[len(b.buf)-1]
 	d := cast(^mem.Raw_Dynamic_Array)&b.buf
 	d.len = max(d.len-1, 0)
 	return
 }
 
+// pops the last rune in the builder and returns the popped rune and its rune width
+// returns 0, 0 when the builder is empty
 pop_rune :: proc(b: ^Builder) -> (r: rune, width: int) {
+	if len(b.buf) == 0 {
+		return 0, 0
+	}
+
 	r, width = utf8.decode_last_rune(b.buf[:])
 	d := cast(^mem.Raw_Dynamic_Array)&b.buf
 	d.len = max(d.len-width, 0)
 	return
 }
 
-
 @(private)
 DIGITS_LOWER := "0123456789abcdefx"
 
+// overload for `write_quoted_string_*` variants
 write_quoted_string :: proc{
 	write_quoted_string_builder,
 	write_quoted_string_writer,
 }
 
+/*
+	append a quoted string into the builder, return the written byte size
+
+	builder := strings.make_builder()
+	strings.write_quoted_string(&builder, "a") // 3
+	strings.write_quoted_string(&builder, "bc", '\'') // 4	
+	strings.write_quoted_string(&builder, "xyz") // 5
+	fmt.println(strings.to_string(builder)) // -> "a"'bc'xyz"
+*/
 write_quoted_string_builder :: proc(b: ^Builder, str: string, quote: byte = '"') -> (n: int) {
 	n, _ = io.write_quoted_string(to_writer(b), str, quote)
 	return
@@ -228,11 +322,13 @@ write_quoted_string_writer :: proc(w: io.Writer, str: string, quote: byte = '"')
 	return	
 }
 
+// overload for `write_encoded_rune_*`
 write_encoded_rune :: proc{
 	write_encoded_rune_builder,
 	write_encoded_rune_writer,
 }
 
+// appends a rune to the builder, optional `write_quote` boolean tag, returns the written rune size
 write_encoded_rune_builder :: proc(b: ^Builder, r: rune, write_quote := true) -> (n: int) {
 	n, _ = io.write_encoded_rune(to_writer(b), r, write_quote)
 	return
@@ -244,12 +340,15 @@ write_encoded_rune_writer :: proc(w: io.Writer, r: rune, write_quote := true) ->
 	return
 }
 
-
+// overload for `write_escaped_rune_*`
 write_escaped_rune :: proc{
 	write_escaped_rune_builder,
 	write_escaped_rune_writer,
 }
 
+// appends a rune to the builder, fully written out in case of escaped runes e.g. '\a' will be written as such
+// when `r` and `quote` match and `quote` is `\\` - they will be written as two slashes
+// `html_safe` flag in case the runes '<', '>', '&' should be encoded as digits e.g. `\u0026`
 write_escaped_rune_builder :: proc(b: ^Builder, r: rune, quote: byte, html_safe := false) -> (n: int) {
 	n, _ = io.write_escaped_rune(to_writer(b), r, quote, html_safe)
 	return
@@ -261,21 +360,26 @@ write_escaped_rune_writer :: proc(w: io.Writer, r: rune, quote: byte, html_safe
 	return
 }
 
-
+// writes a u64 value `i` in `base` = 10 into the builder, returns the written amount of characters
 write_u64 :: proc(b: ^Builder, i: u64, base: int = 10) -> (n: int) {
 	buf: [32]byte
 	s := strconv.append_bits(buf[:], i, base, false, 64, strconv.digits, nil)
 	return write_string(b, s)
 }
+
+// writes a i64 value `i` in `base` = 10 into the builder, returns the written amount of characters
 write_i64 :: proc(b: ^Builder, i: i64, base: int = 10) -> (n: int) {
 	buf: [32]byte
 	s := strconv.append_bits(buf[:], u64(i), base, true, 64, strconv.digits, nil)
 	return write_string(b, s)
 }
 
+// writes a uint value `i` in `base` = 10 into the builder, returns the written amount of characters
 write_uint :: proc(b: ^Builder, i: uint, base: int = 10) -> (n: int) {
 	return write_u64(b, u64(i), base)
 }
+
+// writes a int value `i` in `base` = 10 into the builder, returns the written amount of characters
 write_int :: proc(b: ^Builder, i: int, base: int = 10) -> (n: int) {
 	return write_i64(b, i64(i), base)
 }

core/strings/conversion.odin

@@ -58,6 +58,13 @@ to_valid_utf8 :: proc(s, replacement: string, allocator := context.allocator) ->
 	return to_string(b)
 }
 
+/*
+	returns the input string `s` with all runes set to lowered case
+	always allocates using the `allocator`
+
+	strings.to_lower("test") -> test	
+	strings.to_lower("Test") -> test	
+*/
 to_lower :: proc(s: string, allocator := context.allocator) -> string {
 	b: Builder
 	init_builder(&b, 0, len(s), allocator)
@@ -66,6 +73,14 @@ to_lower :: proc(s: string, allocator := context.allocator) -> string {
 	}
 	return to_string(b)
 }
+
+/*
+	returns the input string `s` with all runes set to upper case
+	always allocates using the `allocator`
+
+	strings.to_lower("test") -> TEST
+	strings.to_lower("Test") -> TEST
+*/
 to_upper :: proc(s: string, allocator := context.allocator) -> string {
 	b: Builder
 	init_builder(&b, 0, len(s), allocator)
@@ -75,13 +90,13 @@ to_upper :: proc(s: string, allocator := context.allocator) -> string {
 	return to_string(b)
 }
 
-
-
-
+// returns true when the `c` rune is a space, '-' or '_' 
+// useful when treating strings like words in a text editor or html paths 
 is_delimiter :: proc(c: rune) -> bool {
 	return c == '-' || c == '_' || is_space(c)
 }
 
+// returns true when the `r` rune is a non alpha or `unicode.is_space` rune
 is_separator :: proc(r: rune) -> bool {
 	if r <= 0x7f {
 		switch r {
@@ -101,7 +116,10 @@ is_separator :: proc(r: rune) -> bool {
 	return unicode.is_space(r)
 }
 
-
+/*
+	iterator that loops through the string and calls the callback with the `prev`, `curr` and `next` rune
+	on empty string `s` the callback gets called once with empty runes
+*/
 string_case_iterator :: proc(w: io.Writer, s: string, callback: proc(w: io.Writer, prev, curr, next: rune)) {
 	prev, curr: rune
 	for next in s {
@@ -122,8 +140,9 @@ string_case_iterator :: proc(w: io.Writer, s: string, callback: proc(w: io.Write
 	}
 }
 
-
 to_lower_camel_case :: to_camel_case
+
+// converts the `s` string to "lowerCamelCase"
 to_camel_case :: proc(s: string, allocator := context.allocator) -> string {
 	s := s
 	s = trim_space(s)
@@ -147,6 +166,8 @@ to_camel_case :: proc(s: string, allocator := context.allocator) -> string {
 }
 
 to_upper_camel_case :: to_pascal_case
+
+// converts the `s` string to "PascalCase"
 to_pascal_case :: proc(s: string, allocator := context.allocator) -> string {
 	s := s
 	s = trim_space(s)
@@ -169,6 +190,15 @@ to_pascal_case :: proc(s: string, allocator := context.allocator) -> string {
 	return to_string(b)
 }
 
+/* 
+	returns the `s` string to words seperated by the given `delimiter` rune
+	all runes will be upper or lowercased based on the `all_uppercase` bool
+
+	strings.to_delimiter_case("Hello World", '_', false) -> hello_world
+	strings.to_delimiter_case("Hello World", ' ', true) -> HELLO WORLD
+	strings.to_delimiter_case("Hello World", ' ', true) -> HELLO WORLD
+	strings.to_delimiter_case("aBC", '_', false) -> a_b_c
+*/
 to_delimiter_case :: proc(s: string, delimiter: rune, all_upper_case: bool, allocator := context.allocator) -> string {
 	s := s
 	s = trim_space(s)
@@ -208,24 +238,34 @@ to_delimiter_case :: proc(s: string, delimiter: rune, all_upper_case: bool, allo
 	return to_string(b)
 }
 
-
+/* 
+	converts the `s` string to "snake_case" with all runes lowercased
+	
+	strings.to_snake_case("HelloWorld") -> hello_world
+	strings.to_snake_case("Hello World") -> hello_world
+*/
 to_snake_case :: proc(s: string, allocator := context.allocator) -> string {
 	return to_delimiter_case(s, '_', false, allocator)
 }
 
 to_screaming_snake_case :: to_upper_snake_case
+
+// converts the `s` string to "SNAKE_CASE" with all runes uppercased
 to_upper_snake_case :: proc(s: string, allocator := context.allocator) -> string {
 	return to_delimiter_case(s, '_', true, allocator)
 }
 
+// converts the `s` string to "kebab-case" with all runes lowercased
 to_kebab_case :: proc(s: string, allocator := context.allocator) -> string {
 	return to_delimiter_case(s, '-', false, allocator)
 }
 
-to_upper_case :: proc(s: string, allocator := context.allocator) -> string {
+// converts the `s` string to "KEBAB-CASE" with all runes uppercased
+to_upper_kebab_case :: proc(s: string, allocator := context.allocator) -> string {
 	return to_delimiter_case(s, '-', true, allocator)
 }
 
+// converts the `s` string to "Ada_case"
 to_ada_case :: proc(s: string, allocator := context.allocator) -> string {
 	delimiter :: '_'
 

core/strings/intern.odin

@@ -2,21 +2,26 @@ package strings
 
 import "core:mem"
 
+// custom string entry struct
 Intern_Entry :: struct {
 	len:  int,
 	str:  [1]byte, // string is allocated inline with the entry to keep allocations simple
 }
 
+// "intern" is a more memory efficient string map
+// `allocator` is used to allocate the actual `Intern_Entry` strings
 Intern :: struct {
 	allocator: mem.Allocator,
 	entries: map[string]^Intern_Entry,
 }
 
+// initialize the entries map and set the allocator for the string entries
 intern_init :: proc(m: ^Intern, allocator := context.allocator, map_allocator := context.allocator) {
 	m.allocator = allocator
 	m.entries = make(map[string]^Intern_Entry, 16, map_allocator)
 }
 
+// free the map and all its content allocated using the `.allocator`
 intern_destroy :: proc(m: ^Intern) {
 	for _, value in m.entries {
 		free(value, m.allocator)
@@ -24,15 +29,22 @@ intern_destroy :: proc(m: ^Intern) {
 	delete(m.entries)
 }
 
+// returns the `text` string from the intern map - gets set if it didnt exist yet
+// the returned string lives as long as the map entry lives
 intern_get :: proc(m: ^Intern, text: string) -> string {
 	entry := _intern_get_entry(m, text)
 	#no_bounds_check return string(entry.str[:entry.len])
 }
+
+// returns the `text` cstring from the intern map - gets set if it didnt exist yet
+// the returned cstring lives as long as the map entry lives
 intern_get_cstring :: proc(m: ^Intern, text: string) -> cstring {
 	entry := _intern_get_entry(m, text)
 	return cstring(&entry.str[0])
 }
 
+// looks up wether the `text` string exists in the map, returns the entry
+// sets & allocates the entry if it wasnt set yet
 _intern_get_entry :: proc(m: ^Intern, text: string) -> ^Intern_Entry #no_bounds_check {
 	if prev, ok := m.entries[text]; ok {
 		return prev

core/strings/reader.odin

@@ -3,46 +3,60 @@ package strings
 import "core:io"
 import "core:unicode/utf8"
 
+/*
+	io stream data for a string reader that can read based on bytes or runes
+	implements the vtable when using the io.Reader variants
+	"read" calls advance the current reading offset `i`
+*/
 Reader :: struct {
 	s:         string, // read-only buffer
 	i:         i64,    // current reading index
 	prev_rune: int,    // previous reading index of rune or < 0
 }
 
+// init the reader to the string `s` 
 reader_init :: proc(r: ^Reader, s: string) {
 	r.s = s
 	r.i = 0
 	r.prev_rune = -1
 }
 
+// returns a stream from the reader data
 reader_to_stream :: proc(r: ^Reader) -> (s: io.Stream) {
 	s.stream_data = r
 	s.stream_vtable = _reader_vtable
 	return
 }
 
+// init a reader to the string `s` and return an io.Reader
 to_reader :: proc(r: ^Reader, s: string) -> io.Reader {
 	reader_init(r, s)
 	rr, _ := io.to_reader(reader_to_stream(r))
 	return rr
 }
+
+// init a reader to the string `s` and return an io.Reader_At
 to_reader_at :: proc(r: ^Reader, s: string) -> io.Reader_At {
 	reader_init(r, s)
 	rr, _ := io.to_reader_at(reader_to_stream(r))
 	return rr
 }
+
+// init a reader to the string `s` and return an io.Byte_Reader
 to_byte_reader :: proc(r: ^Reader, s: string) -> io.Byte_Reader {
 	reader_init(r, s)
 	rr, _ := io.to_byte_reader(reader_to_stream(r))
 	return rr
 }
+
+// init a reader to the string `s` and return an io.Rune_Reader
 to_rune_reader :: proc(r: ^Reader, s: string) -> io.Rune_Reader {
 	reader_init(r, s)
 	rr, _ := io.to_rune_reader(reader_to_stream(r))
 	return rr
 }
 
-
+// remaining length of the reader 
 reader_length :: proc(r: ^Reader) -> int {
 	if r.i >= i64(len(r.s)) {
 		return 0
@@ -50,10 +64,13 @@ reader_length :: proc(r: ^Reader) -> int {
 	return int(i64(len(r.s)) - r.i)
 }
 
+// returns the string length stored by the reader
 reader_size :: proc(r: ^Reader) -> i64 {
 	return i64(len(r.s))
 }
 
+// reads len(p) bytes into the slice from the string in the reader
+// returns `n` amount of read bytes and an io.Error
 reader_read :: proc(r: ^Reader, p: []byte) -> (n: int, err: io.Error) {
 	if r.i >= i64(len(r.s)) {
 		return 0, .EOF
@@ -63,6 +80,9 @@ reader_read :: proc(r: ^Reader, p: []byte) -> (n: int, err: io.Error) {
 	r.i += i64(n)
 	return
 }
+
+// reads len(p) bytes into the slice from the string in the reader at an offset
+// returns `n` amount of read bytes and an io.Error
 reader_read_at :: proc(r: ^Reader, p: []byte, off: i64) -> (n: int, err: io.Error) {
 	if off < 0 {
 		return 0, .Invalid_Offset
@@ -76,6 +96,8 @@ reader_read_at :: proc(r: ^Reader, p: []byte, off: i64) -> (n: int, err: io.Erro
 	}
 	return
 }
+
+// reads and returns a single byte - error when out of bounds
 reader_read_byte :: proc(r: ^Reader) -> (byte, io.Error) {
 	r.prev_rune = -1
 	if r.i >= i64(len(r.s)) {
@@ -85,6 +107,8 @@ reader_read_byte :: proc(r: ^Reader) -> (byte, io.Error) {
 	r.i += 1
 	return b, nil
 }
+
+// decreases the reader offset - error when below 0
 reader_unread_byte :: proc(r: ^Reader) -> io.Error {
 	if r.i <= 0 {
 		return .Invalid_Unread
@@ -93,6 +117,8 @@ reader_unread_byte :: proc(r: ^Reader) -> io.Error {
 	r.i -= 1
 	return nil
 }
+
+// reads and returns a single rune and the rune size - error when out bounds
 reader_read_rune :: proc(r: ^Reader) -> (ch: rune, size: int, err: io.Error) {
 	if r.i >= i64(len(r.s)) {
 		r.prev_rune = -1
@@ -107,6 +133,9 @@ reader_read_rune :: proc(r: ^Reader) -> (ch: rune, size: int, err: io.Error) {
 	r.i += i64(size)
 	return
 }
+
+// decreases the reader offset by the last rune
+// can only be used once and after a valid read_rune call
 reader_unread_rune :: proc(r: ^Reader) -> io.Error {
 	if r.i <= 0 {
 		return .Invalid_Unread
@@ -118,6 +147,8 @@ reader_unread_rune :: proc(r: ^Reader) -> io.Error {
 	r.prev_rune = -1
 	return nil
 }
+
+// seeks the reader offset to a wanted offset 
 reader_seek :: proc(r: ^Reader, offset: i64, whence: io.Seek_From) -> (i64, io.Error) {
 	r.prev_rune = -1
 	abs: i64
@@ -138,6 +169,8 @@ reader_seek :: proc(r: ^Reader, offset: i64, whence: io.Seek_From) -> (i64, io.E
 	r.i = abs
 	return abs, nil
 }
+
+// writes the string content left to read into the io.Writer `w`
 reader_write_to :: proc(r: ^Reader, w: io.Writer) -> (n: i64, err: io.Error) {
 	r.prev_rune = -1
 	if r.i >= i64(len(r.s)) {
@@ -157,7 +190,6 @@ reader_write_to :: proc(r: ^Reader, w: io.Writer) -> (n: i64, err: io.Error) {
 	return
 }
 
-
 @(private)
 _reader_vtable := &io.Stream_VTable{
 	impl_size = proc(s: io.Stream) -> i64 {