package zed

  1. Overview
  2. Docs

Module Zed_charSource

Sourcetype t

The type for glyphs.

To represent a grapheme in unicode is a bit more complicated than what is expected: a printable UChar. For example, diacritics are added to IPA(international phonetic alphabet) letter to produce a modified pronunciation. Variation selectors are added to a CJK character to specify a specific glyph variant for the character.

Therefore the logical type definition of Zed_char.t can be seen as

  type Zed_char.t= {
    core: UChar.t;
    combined: UChar.t list;
  }
Sourcetype char_prop =
  1. | Printable of int
  2. | Other
  3. | Null

The property of a character. It can be either Printable of width, Other(unprintable character) or Null(code 0).

Sourceval to_raw : t -> Uchar.t list
Sourceval to_array : t -> Uchar.t array
Sourceval core : t -> Uchar.t

core char returns the core of the char

Sourceval combined : t -> Uchar.t list

combined char returns the combining marks of the char

Sourceval unsafe_of_utf8 : string -> t

unsafe_of_utf8 str returns a zed_char from utf8 encoded str without any validation.

Sourceval of_utf8 : ?indv_combining:bool -> string -> t

of_utf8 str returns a zed_char from utf8 encoded str. This function checks whether str represents a single UChar or a legal grapheme, i.e. a printable core with optional combining marks. It will raise Failure "malformed Zed_char sequence" If the validation is not passed.

  • parameter indv_combining

    allow to create a Zed_char.t from a single combining mark, default to true

Sourceval to_utf8 : t -> string

to_utf8 chr converts a chr to a string encoded in UTF-8.

Sourceval zero : t

The Character 0.

Sourceval prop_uChar : Uchar.t -> char_prop

prop_uChar uChar returns the char_prop of uChar

Sourceval prop : t -> char_prop

prop ch returns the char_prop of ch

Sourceval is_printable : Uchar.t -> bool

Returns whether a Uchar.t is a printable character or not.

Sourceval is_printable_core : Uchar.t -> bool

Returns whether a Uchar.t is a printable character and its width is not zero.

Sourceval is_combining_mark : Uchar.t -> bool

Returns whether a Uchar.t is a combining mark.

Sourceval size : t -> int

size ch returns the size (number of characters) of ch.

Sourceval length : t -> int

Aliase of size

Sourceval width : t -> int

width ch returns the width of ch.

Sourceval out_of_range : t -> int -> bool

out_of_range ch idx returns whether idx is out of range of ch.

Sourceval get : t -> int -> Uchar.t

get ch n returns the n-th character of ch.

Sourceval get_opt : t -> int -> Uchar.t option

get ch n returns an optional value of the n-th character of ch.

Sourceval append : t -> Uchar.t -> t

append ch cm append the combining mark cm to ch and returns it. If cm is not a combining mark, then the original ch is returned.

Sourceval compare_core : t -> t -> int

compare_core ch1 ch2 compares the core components of ch1 and ch2

Sourceval compare_raw : t -> t -> int

compare_raw ch1 ch2 compares over the internal characters of ch1 and ch2 sequentially

Sourceval compare : t -> t -> int

Alias of compare_raw

Sourceval mix_uChar : t -> Uchar.t -> (t, t) Result.result

mix_uChar chr uChar tries to append uChar to chr and returns Ok result. If uChar is not a combining mark, then an Error (Zed_char.t consists of uChar) is returned.

Sourceval of_uChars : ?trim:bool -> ?indv_combining:bool -> Uchar.t list -> t option * Uchar.t list

of_uChars uChars transforms uChars to a tuple. The first value is an optional Zed_char.t and the second is a list of remaining uChars. The optional Zed_char.t is either a legal grapheme(a core printable char with optinal combining marks) or a wrap for an arbitrary Uchar.t. After that, all remaining uChars returned as the second value in the tuple.

  • parameter trim

    trim leading combining marks before transforming, default to false

  • parameter indv_combining

    create a Zed_char from an individual dissociated combining mark, default to true

Sourceval zChars_of_uChars : ?trim:bool -> ?indv_combining:bool -> Uchar.t list -> t list * Uchar.t list

zChars of_uChars uChars transforms uChars to a tuple. The first value is a list of Zed_char.t and the second is a list of remaining uChars.

  • parameter trim

    trim leading combining marks before transforming, default to false

  • parameter indv_combining

    create a Zed_char from an individual dissociated combining mark, default to true

Sourceval for_all : (Uchar.t -> bool) -> t -> bool

for_all p zChar checks if all elements of zChar satisfy the predicate p.

Sourceval iter : (Uchar.t -> unit) -> t -> unit

iter f char applies f on all characters of char.

The prefix 'unsafe_' of unsafe_of_char and unsafe_of_uChar means the two functions do not check if char or uChar being transformed is a valid grapheme. There is no 'safe_' version, because the scenario we should deal with a single char or uChar is when the char sequence are individual, incomplete. For example, when we are reading user input. Even if a user wants to input a legal grapheme, say, 'a' with a hat(a combining mark) on top. the user will input 'a' and then '^' individually, the later combining mark is always illegal. What we should do is to invoke unsafe_of_uChar user_input and send the result to the edit engine. Other modules in zed, like Zed_string, Zed_lines, Zed_edit ... are already well designed to deal with such a situation. They will do combining mark joining, grapheme validation for you automatically. Use the two 'unsafe_' functions directly, you're doing things the right way.

Sourceval unsafe_of_char : char -> t

unsafe_of_char ch returns a Zed_char whose core is ch.

Sourceval unsafe_of_uChar : Uchar.t -> t

unsafe_of_uChar ch returns a Zed_char whose core is ch.