more documentation for map_val, suggested by Stephen Dolan

ocaml · Jan 27, 2021 · 38d3725 · 38d3725
1 parent eb85bd2
commit 38d3725
Showing 1 changed file with 6 additions and 0 deletions.
diff --git a/stdlib/lazy.mli b/stdlib/lazy.mli
@@ -100,6 +100,12 @@ val map_val : ('a -> 'b) -> 'a t -> 'b t
    a suspension, but on the other hand it perform more work eagerly
    that may not be useful if you never force the function result.
 
+   If [f] raises an exception, it will be raised immediately when
+   [is_val x], or raised only when forcing the thunk otherwise.
+
+   If [map_val f x] returns a non-exception result, then
+   [is_map (map_val f x)] is equal to [is_val x].
+
     @since 4.13.0 *)