[hope.git] / src / hope_option.erl

-module(hope_option).

-export_type([ t/1
             ]).

-export([ put/2
        , get/2
        , map/2
        ]).


-type t(A) :: none | {some, A}.


put(X, F) ->
    case F(X)
    of  true  -> {some, X}
    ;   false -> none
    end.


get({some, X}, _) -> X;
get(none     , Y) -> Y.


map({some, X}, F) -> {some, F(X)};
map(none     , _) -> none.
Commit	Line	Data
e492ea13 SK	1	-module(hope_option).
	2
	3	-export_type([ t/1
	4	]).
	5
	6	-export([ put/2
	7	, get/2
	8	, map/2
	9	]).
	10
	11
	12	-type t(A) :: none \| {some, A}.
	13
	14
	15	put(X, F) ->
	16	case F(X)
	17	of true -> {some, X}
	18	; false -> none
	19	end.
	20
	21
	22	get({some, X}, _) -> X;
	23	get(none , Y) -> Y.
	24
	25
	26	map({some, X}, F) -> {some, F(X)};
	27	map(none , _) -> none.