Should users be forced to write out the full fnctl argument in regress?

[taylorokonek]

Currently, users can enter a shortened character string for the fnctl argument in regress, and so long as it corresponds to a unique substring, the function will run. As an example, a user could simply set fnctl = "g", and the function would take this to mean fnctl = "geometric mean". Personally, I don't think there's a huge harm in forcing users to spell out the fnctl argument. Does anyone have any insight as to why this particular functionality was introduced (@bdwilliamson)?

[bdwilliamson]

I don’t remember why we did that, and also think it’s fine to force people to write out the entire functional.