X-Git-Url: https://git.xandkar.net/?a=blobdiff_plain;f=src%2Fhope_option.erl;h=996e3428eeac2cb66a2f4005745352a5fdd6d374;hb=6ab4e7a4779143c308ef34ddc97696215b1b5448;hp=7a8743823e22c5d8be78f56a7ac83a2cb2cf3064;hpb=9a5e47faa30b6f3fbd9b0521b238c2d1076de498;p=hope.git

diff --git a/src/hope_option.erl b/src/hope_option.erl
index 7a87438..996e342 100644
--- a/src/hope_option.erl
+++ b/src/hope_option.erl
@@ -7,15 +7,19 @@
     ]).
 
 -export(
-    [ put/2
-    , get/2
-    , return/1
-    , return/2
+    % Generic monad interface
+    [ return/1
     , map/2
-    , iter/2
     , pipe/2
+
+    % Specific to hope_option:t()
+    , return/2
+    , put/2
+    , get/2
+    , iter/2
     , of_result/1
     , of_undefined/1
+    , validate/2
     ]).
 
 
@@ -77,3 +81,13 @@ of_result({error, _}) -> none.
     t(A).
 of_undefined(undefined) -> none;
 of_undefined(X)         -> {some, X}.
+
+-spec validate(t(A), fun((A) -> boolean())) ->
+    t(A).
+validate(none, _) ->
+    none;
+validate({some, X}=T, F) ->
+    case F(X)
+    of  false -> none
+    ;   true  -> T
+    end.