Everything you said has nothing to do with lenses and everything to do with trying to satisfy some statically-typed aesthetics. > First, it's possible that dif

Everything you said has nothing to do with lenses and everything to do with trying to satisfy some statically-typed aesthetics. > First, it's possible that different elements of an array or different properties of an object has different shapes I can't imagine how this would introduce any sort of difficulties w.r.t. lenses that aren't already present with normal getting and setting of nested structures (aka probably not much). > Second, it's just difficult to get things right without a compiler's help This has nothing to do with lenses and everything to do with you preferring the feel of static types. You go on to talk about a bunch of issues with complex constructs that really only exist in static typing. Sometimes you write a wrong thing and get a runtime error. This happens in all dynamically typed languages (and many statically typed as well). > Furthermore, without types... this rather elegant unification of getter and setter seems to be lost. Like ya do. I don't see how this has any impact at all on developing applications.