On 2011-06-06 7:51 AM, Ralph Boland wrote:
> If there is a conventional solution to this problem I would of course
> like to know what it is and where
> it is used.

SML's syntax forbids use of the same operator in unary and binary 
contexts, so it distinguishes between unary minus and binary minus. 
SML's unary minus operator is tilde "~", so you could write:

      '~9,~5-~3,~1-4,7,11-15'

for the problem example.

Another option could be to use interval syntax:

      '-9 [-5 -3] [-1 4] 7 [11 15]'

with or without commas.

Regards,
   Tony