Re: [Groff] parsing a corner specification

[Keith Marshall]

On Tuesday 21 August 2007 06:42, Werner LEMBERG wrote:
> Well, it seems that you've hit a behaviour which is (a) quite obscure
> since there has never been a report about it,

Perhaps because the expression in question is not just obscure, but is 
rather unnatural.  Given the preceding

  .PS
  A: circle "A"

what is the intent of

  B: A left

IOW, to which *object* is the label `B' to refer?  Since, this is 
followed by

  circle "B" at B
  .PE

presumably the intention is to create a reference to a location, rather 
than to an object, but surely the more natural way to express this is

  .PS
  A: circle "A"
  B: circle "B" at A.w
  .PE

which causes B to refer to the intended location, i.e. the centre of  
the circle object `B', which becomes coincident with the location of 
the leftmost extremity of the circle object `A'.  Certainly, this is 
the way I would write it, and I suspect that most other regular pic 
users would do likewise, so it is unlikely that the anomalous behaviour 
would have been discovered in normal usage.

> Feel free to remove it completely in case it is
> the most convenient solution.

FWIW, I believe that the usage

  B: A left

and also

  B: A upper left

are erroneous; IMO, both should be rejected.

Regards,
Keith.