to_int m is the number of the month m.

of_int n returns month of the number n. If n < 1 or n > 12, it returns an error.

of_int_exn is an alias on of_int except that if user give an invalid number, we raise an exception.

to_stirng v returns a well-formed string from a month v.

of_string v returns a month from a well-formed string v. Process is case-sensitive, month needs to be capitalized (eg. "Nov").

of_string v returns a month from a well-formed string v. Process is case-sensitive, month needs to be capitalized (eg. "Nov").

• raises [Invalid_argument]

  when v is an invalid month.

Alias of of_string_exn.