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Comment by felixgallo | Hacker News Reader

Out of curiosity, did you try using dialyzer? I understand ADTs are strictly better, but was there a particular problem that dialyzer couldn't pragmatically solve for you?

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Yes, while Dialyzer was somewhat useful, it only seemed to catch a subset of possible errors. The set of errors it missed was large enough that I just gave up on Erlang altogether.

I never took the time to figure out what Dialyzer could and couldn't catch. This was a few years ago, so I don't really have any particular examples in mind anymore, but IIRC it may have had to do with being mostly unable to validate the structure of tuples as parameters to functions.

  > validate the structure of tuples as parameters to
  > functions.

Dialyzer can definitely do that, you just need to specify a type that is a tuple:

    -type something() :: {Thing  :: thingtype(),
                          Thing2 :: thing2type()}.
    %% ...
    -spec foo(something()) -> thingtype().

But I agree that Dialyzer can feel incomplete. It's been a little while now but I recall having to use `term()' in specs (basically, untyped) to suppress false positives in some cases. It was also quite slow.

Still, a much better situation than Ruby.

Also worth noting that erlc catches typos, again unlike Ruby.

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