computer-go: Lowercase letters in SGF

[Darren Cook <darren@xxxxxxxxx>]

A quick question about SGF format. It (*) says a property can be made up of 
capital letters:
  PropIdent  = UcLetter { UcLetter }

But lowercase letters are also allowed aren't they? E.g. "SZ[19]" or 
"SiZe[19]" are both valid? If not, did this used to be allowed as I'm sure 
I've seen it.

If allowed, are leading lowercase characters also valid? E.g. 
"boardSiZe[19]". Or should this cause an invalid-sgf-format error?

Darren


*: http://www.red-bean.com/sgf/sgf4.html