## `builtin`: base types and constructors

  This module defines some types and exceptions for which the language provides special syntax, and are therefore treated specially by the compiler.

    type int
    type float
    type string
    type char

  The types of integers, floating-point numbers, character strings, and characters, respectively.

    type exn

  The type of exception values.

    type bool = false | true

  The type of boolean values.

    type 'a vect

  The type of arrays whose elements have type `'a`.

    type unit = ()

  The type of the unit value.

    type 'a list = [] | prefix :: of 'a * 'a list

  The type of lists.

    type 'a option = None | Some of 'a

  The type of optional values.

    exception Match_failure of string * int * int

  The exception raised when a pattern-matching fails. The argument indicates the position in the source code of the pattern-matching (source file name, position of the first character of the matching, position of the last character.