Here's a practical example: I have found a concatenative language (Factor, specifically) to be extremely useful for use in a workflow system. In particular, s

Here's a practical example: I have found a concatenative language (Factor, specifically) to be extremely useful for use in a workflow system. In particular, since it's not applicative, there's no API between "words", so it's damn near trivial to combine workflow sequences together -- no API is necessary. Each sequence of words (think of it as a workflow) can consume and or produce as much data as needed -- again, without any API coordination whatsoever.