[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Ellipsis in the _pattern_

This page is part of the web mail archives of SRFI 46 from before July 7th, 2015. The new archives for SRFI 46 contain all messages, not just those from before July 7th, 2015.

On Sat, 11 Oct 2003, Taylor Campbell wrote:

>[ Slippinrippindangfangrottenzargbargadingdong!  I did it _again_! ]

>You've lost me here.  Ellipsis is for matching a sequence; how can
>match literal ellipsis?  Are you talking about an arbitrarily nested
>of ellipses, i.e. to be matched with (::: ...), in which case we _still_
>need :::?

You know, if it doesn't make sense to you it probably means the thing I'm
thinking about is a nonissue anyway.  As I said, I haven't eaten and breathed
enough macrology to fully understand the intent of ::: in the first place.
I just have the impression that if we actually need it, then something might
break down if we want to go to meta-macros or meta-meta macros and don't
have a corresponding "nested" form or the ability to produce/match it in
the inputs to our higher-order macros.

Still, the reason I doubt its actual utility is that I don't think anything
prevents ...  from matching a "sequence" of length one whose only member is
another ellipsis.

Maybe I should get embarassed about my ignorance here and shut up.