I was reading a Stack Overflow answer here and argued with the author that his wording is confusing, but now I'm not so sure if I'm right.

The phrase in question is:

If a type T adopts the protocol and does not define T.IndexDistance otherwise then T.IndexDistance becomes a type alias for Int

The author initially had it written as 'otherwise, then', later removed the comma. Still to me it doesn't make sense.

To me it seems you have to either of these:

  • otherwise, xyz
  • otherwise, the
  • then

'otherwise then' is just redundant. It's like making two right turns when you need one.

  • 1
    Is there a comma missing? Apr 6, 2018 at 14:06
  • can you see my edit?
    – Honey
    Apr 6, 2018 at 14:14
  • I'd retain the comma to make for easier parsing. // There were once many arguments of the form 'If, then, therefore' (If A is true, it follows that B and then C are also true) (at least in teaching in the UK): so many that the name stuck. Obviously, there doesn't usually need to be a 'then' in 'If A is true, then B is true'. But redundancy isn't wrong per se, and I'd say that including it here is another aid to readability. Apr 6, 2018 at 14:53
  • 3
    I'm voting to close this question as off-topic because this site is not about programming language. Apr 6, 2018 at 17:13
  • 1
    @user9825893y50932 Everyone has their vote, but to me that's absurd. I'm just asking whether or not 'otherwise then' is a correct construct. The context of it can be anything. In my case it was programming language.
    – Honey
    Apr 6, 2018 at 17:15

1 Answer 1


If I understand correctly, you interpreted the answer as "other than", as in "a number other than 0". However, I think the author meant that "T.IndexDistance becomes a type alias for Int unless T.IndexDistance is defined otherwise". The author was therefore correct in his original wording, and the critical comma should not have been removed.

That being said, a usage of "otherwise then" as a comparison is incorrect for several reasons:

  • then is an adverb meaning at that time, afterwards, therefore (OED). The correct word for a comparison would be the preposition than;

  • otherwise than is, as you said, redundant;

  • such a usage would not make sense in the given context, as one cannot "define T.IndexDistance differently than T.IndexDistance".

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