Name map

[domoritz]

There seems to be a lot of confusion about having to set domain and range explicitly. See e.g. vega/altair#278. Would it be easier if users could specify a map (key, value) that does the renaming?

[kanitw]

I disagree.

1. That issue is asking for a way for replacing short labels with long labels, which should be done by adding a generic replace transform Replace Transform #1761, IMHO.

2. This will introduce two ways of doing the same which you're against most of the time.
   Instead of committing to that early. I would like to note that we haven't documented how to set custom domain and range very well. Thus, I suggest that we do that, close this issue, and we can still consider doing this in the future if there are more people complaining.

[domoritz]

I think what I'm asking for is a replace transform. The reason why a map is better than two arrays is that it can be partial and is order independent. I do not want two ways to do the same things but would rather replace one.

Closing in favor of better docs and #1761.