Re: An m4 puzzlement.

Thanks for your reply to my message.

  M4 1.4 does not support ERE expressions, so [[:alpha:]]* is read as zero or
  more characters from the set `[:alph]'.  I didn't check whether your quoting
  is correct, but you should have more luck with `^[a-zA-Z]*$'.

Using explicit character ranges worked.  It had occurred to me that the posix
character class might have been the problem, but, like Voltaire, I was sitting
in the smallest room of the house when I thought about it, and by the time I
got near something that would let me check, my mind had dropped the thought and
fluttered on to other things.  Thanks again for your help.