Uchar(3)

okay so this is Uchar(3), straight from the OCaml library manual, and it's literally the module for Unicode characters. bestie, we're about to get into scalar values, UTF decodes, and hash functions — no cap, it's giving foundational 💅

🎀 NAME 🎀

Uchar - Unicode characters.

🦋 Module 🦋

the module line is literally:

Module   Module   Uchar

yes, it says Module twice. iconic.

✨ Documentation ✨

the signature is literally:

Module Uchar
 : sig end

Unicode characters.

Since 4.03

• type t — the type for Unicode characters. A value of this type represents a Unicode scalar value which is an integer in the ranges 0x0000 ... 0xD7FF or 0xE000 ... 0x10FFFF.
• val min : t — min is U+0000.
• val max : t — max is U+10FFFF.
• val bom : t — bom is U+FEFF, the byte order mark (BOM) character. Since 4.06
• val rep : t — rep is U+FFFD, the replacement character. Since 4.06
• val succ : t -> t — succ u is the scalar value after u in the set of Unicode scalar values. Raises Invalid_argument if u is Uchar.max.
• val pred : t -> t — pred u is the scalar value before u in the set of Unicode scalar values. Raises Invalid_argument if u is Uchar.min.
• val is_valid : int -> bool — is_valid n is true if and only if n is a Unicode scalar value (i.e. in the ranges 0x0000 ... 0xD7FF or 0xE000 ... 0x10FFFF).
• val of_int : int -> t — of_int i is i as a Unicode character. Raises Invalid_argument if i does not satisfy Uchar.is_valid.
• val to_int : t -> int — to_int u is u as an integer.
• val is_char : t -> bool — is_char u is true if and only if u is a latin1 OCaml character.
• val of_char : char -> t — of_char c is c as a Unicode character.
• val to_char : t -> char — to_char u is u as an OCaml latin1 character. Raises Invalid_argument if u does not satisfy Uchar.is_char.
• val equal : t -> t -> bool — equal u u' is u = u'.
• val compare : t -> t -> int — compare u u' is Stdlib.compare u u'.
• val seeded_hash : int -> t -> int — seeded_hash seed u is a seeded hash function with the same output value as Hashtbl.seeded_hash. This function allows this module to be passed as an argument to the functor Hashtbl.MakeSeeded. Since 5.3
• val hash : t -> int — an unseeded hash function with the same output value as Hashtbl.hash. This function allows this module to be passed as an argument to the functor Hashtbl.Make. Before5.3 — the hashing algorithm was different. Use Hashtbl.rebuild for stored tables which used this hashing function.

🌈 UTF codecs tools 🌈

• type utf_decode — the type for UTF decode results. Values of this type represent the result of a Unicode Transformation Format decoding attempt.
• val utf_decode_is_valid : utf_decode -> bool — utf_decode_is_valid d is true if and only if d holds a valid decode.
• val utf_decode_uchar : utf_decode -> t — utf_decode_uchar d is the Unicode character decoded by d if utf_decode_is_valid d is true and Uchar.rep otherwise.
• val utf_decode_length : utf_decode -> int — utf_decode_length d is the number of elements from the source that were consumed by the decode d. This is always strictly positive and smaller or equal to 4. The kind of source elements depends on the actual decoder; for the decoders of the standard library this function always returns a length in bytes.
• val utf_decode : int -> t -> utf_decode — utf_decode n u is a valid UTF decode for u that consumed n elements from the source for decoding. n must be positive and smaller or equal to 4 (this is not checked by the module).
• val utf_decode_invalid : int -> utf_decode — utf_decode_invalid n is an invalid UTF decode that consumed n elements from the source to error. n must be positive and smaller or equal to 4 (this is not checked by the module). The resulting decode has Uchar.rep as the decoded Unicode character.
• val utf_8_decode_length_of_byte : char -> int — utf_8_decode_length_of_byte byte is the number of bytes, from 1 to Uchar.max_utf_8_decode_length, that a valid UTF-8 decode starting with byte byte would consume or 0 if byte cannot start a valid decode. Since 5.4
• val max_utf_8_decode_length : int — max_utf_8_decode_length is 4, the maximal number of bytes a valid or invalid UTF-8 decode can consume. Since 5.4
• val utf_8_byte_length : t -> int — utf_8_byte_length u is the number of bytes needed to encode u in UTF-8.
• val utf_16_byte_length : t -> int — utf_16_byte_length u is the number of bytes needed to encode u in UTF-16.

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mwah 💋 — generated by OCamldoc on 2026-06-22, and this was Uchar(3). slay, bye 🫶