Lexer(3)

💖 Lexer(3) 💖

okay so bestie, welcome to Lexer(3) from the OCaml library — the page for the lexical analyzer. Yes, the manual name is literally Lexer(3), and we are reading it together like the iconic little docs nerds we are. 🫶✨

🌸 NAME 🌸

Lexer — the lexical analyzer. That's the name, that's the vibe, periodt. 💅

🧚 Module 🧚

Module Lexer — and the signature is right here:

Module Lexer
 : sig end

✨ Documentation ✨

Module Lexer : sig end shows up again in the docs, because of course it does. Then comes the sentence The lexical analyzer — main character energy, honestly. 🌟

Warning: this module is unstable and part of Compiler_libs .

Not me being dramatic — that's literally the warning. 💀

Here are the values, in order, no skipping:

• val init : ?keyword_edition:(int * int) option * string list -> unit -> unit — the init signature, exactly as written. Keep the ?keyword_edition bits and the double -> unit -> unit energy. ✨
• val token : Lexing.lexbuf -> Parser.token — takes a Lexing.lexbuf, gives you a Parser.token.
• val skip_hash_bang : Lexing.lexbuf -> unit — takes a Lexing.lexbuf and returns unit. The name says skip_hash_bang, and we are respectfully not adding extra lore. 🎀

Then we hit type error =, and every single constructor is here, bestie:

type error =
 | Illegal_character of char
 | Illegal_escape of string * string option
 | Reserved_sequence of string * string option
 | Unterminated_comment of Location.t
 | Unterminated_string
 | Unterminated_string_in_comment of Location.t * Location.t
 | Empty_character_literal
 | Keyword_as_label of string
 | Capitalized_label of string
 | Invalid_literal of string
 | Invalid_directive of string * string option
 | Invalid_encoding of string
 | Invalid_char_in_ident of Uchar.t
 | Non_lowercase_delimiter of string
 | Capitalized_raw_identifier of string
 | Unknown_keyword of string

And it comes with this exception, exactly:

exception Error of error * Location.t

More values, keep scrolling bestie:

• val in_comment : unit -> bool — takes unit, returns a bool, so it's giving yes/no energy. 💜
• val in_string : unit -> bool — same shape: unit -> bool. Literally named in_string, no notes. 🦋
• val is_keyword : string -> bool — string goes in, bool comes out.
• val print_warnings : bool ref — a bool ref, so it's a mutable flag moment. 🔥
• val handle_docstrings : bool ref — another bool ref, same exact shape. 🌸
• val comments : unit -> (string * Location.t) list — returns a list of (string * Location.t), exactly. 🎀
• val token_with_comments : Lexing.lexbuf -> Parser.token — Lexing.lexbuf to Parser.token, with the exact token_with_comments signature. ⭐
• val set_preprocessor : (unit -> unit) -> ((Lexing.lexbuf -> Parser.token) -> Lexing.lexbuf -> Parser.token) -> unit — the long iconic one, with those exact function types and unit at the end. Slay. 💅

okay that's the whole page, bestie. Footer cuteness, signed off: OCamldoc, 2026-06-22, Lexer(3). Mwah 💋✨