> My defintion for attribute follows:
>
> rule attribute
> storage? <Attribute>
> end
>
> rule storage
> 'seq'i space? <Storage>
> end
>
> So I think my grammar specifies that attribute may optionally consist
> of the string 'seq'. I don't think there's anything in this
> specification that says accept empty string... is there?
If the "seq" is optional, that means it's ok for it to be absent. And
if it's absent the attribute consists of the empty string. So that rule
says that an attribute can be an empty string.
You probably don't want or need the "?" after storage, and (unless you
plan to have other attributes) you may not even need the attribute
rule--if storage is the only possibility you may just want to specify
storage instead of attribute in the rule above.
-- Markus