Module Stdlib320.Option

Gets the value of an option if it is not None. value o ~default:y is

• x if o = Some x
• y if o = None

A slightly more convenient variant of the previous function, where default y o is equivalent to value o ~default:y.

is_none o is

• true if o = Some x
• false if o = None

is_some o is equivalent to not (is_none o)

Monadic bind for options. It "does something" to the value of the option if it is not None, and passes along the None otherwise. bind o f is

• f x if o = Some x
• None if o = None

Monadic join for options. If collapses an option whose value is an option into a single option. join oo is

• Some x if oo = Some (Some x)
• None if oo = Some None or oo = None

Mapping function for options. It applies a function to the value of the option if the option is not None. map f o is

• Some (f x) if o = Some x
• None if o = None

Folding function for options. fold ~none:x some:f o is equivalent to default x (map f o).

Converts an option to a result. to_result ~none:e o is

• Ok x if o = Some x
• Error e if o = None

Converts an option into a list with zero or one element. It is equivalent to

fold ~none:[] ~some:(fun x -> x :: [])