Period.S

# Module type Period.S

    module type S = sig .. end

Common interface for all periods.

    type +[< Period.date_field ] period

    type t = Period.date_field period

Type of a period.

### Period is an additive monoid

    val empty : [< Period.date_field ] period

The empty period.

    val add : ([< Period.date_field ] as 'a) period ->
           'a period -> 'a period

Addition of periods.

    val sub : ([< Period.date_field ] as 'a) period ->
           'a period -> 'a period

Substraction of periods.

    val opp : ([< Period.date_field ] as 'a) period -> 'a period

Opposite of a period.

### Periods are comparable

    val equal : [< Period.date_field ] period ->
           [< Period.date_field ] period -> bool

Equality function between two periods.
Since 1.09.0
See also Utils.Comparable.equal

    val compare : [< Period.date_field ] period ->
           [< Period.date_field ] period -> int

Comparison function between two periods.
See also Utils.Comparable.compare

    val hash : [< Period.date_field ] period -> int

Hash function for periods.
Since 2.0
See also Utils.Comparable.hash