`type decoded = map list`
`type t`

Represent the a list of mapping in its encoded form.

`val empty : t`

The empty mapping.

`val of_string_unsafe : string -> t`

`of_string_unsafe` does not perform any validation of its argument, unlike `decode`. It is guaranteed that `of_string_unsafe` and `to_string` are inverse functions. Time complexity O(1)

`val decode_exn : t -> decoded`

Parse the mappings.

`val encode : decoded -> t`

Encode the mappings.

`val encode_with_offset : decoded -> Offset.t * t`

Encode the mappings shifted by the returned offset so that the encoded mapping is more compact. This is useful to combining multiple mappings into an `Index.t`

`val number_of_lines : t -> int`
`val first_line : t -> int`
`val to_string : t -> string`

Returns the mappings as a string in the Source map v3 format. Time complexity O(1)