-module(hope_option).
+
-export_type(
[ t/1
]).
[ put/2
, get/2
, map/2
+ , iter/2
+ , of_result/1
]).
.
+-spec put(A, fun((A) -> boolean())) ->
+ t(A).
put(X, F) ->
case F(X)
of true -> {some, X}
; false -> none
end.
-
+-spec get(t(A), Default :: A) ->
+ A.
get({some, X}, _) -> X;
get(none , Y) -> Y.
-
+-spec map(t(A), fun((A) -> (B))) ->
+ t(B).
map({some, X}, F) -> {some, F(X)};
map(none , _) -> none.
+
+-spec iter(t(A), fun((A) -> (ok))) ->
+ ok.
+iter({some, X}, F) -> ok = F(X);
+iter(none , _) -> ok.
+
+-spec of_result(hope_result:t(A, _B)) ->
+ t(A).
+of_result({ok, X}) -> {some, X};
+of_result({error, _}) -> none.