Re: linear syntax?
From: J M Davitt <jdavitt_at_aeneas.net>
Date: Fri, 23 Jun 2006 05:45:22 GMT
Message-ID: <SdLmg.77977$YI5.34887_at_tornado.ohiordc.rr.com>
>
> Okay, I guess that allows parsers that look ahead and then retreat and
> possibly poetry too. I wonder what Codd was trying to disallow,
Date: Fri, 23 Jun 2006 05:45:22 GMT
Message-ID: <SdLmg.77977$YI5.34887_at_tornado.ohiordc.rr.com>
paul c wrote:
> -CELKO- wrote:
>
>>>> What did he mean by linear syntax? << >> >> >> A language that can be parsed from left to right (or vice versa, if you >> are arab; top to bottom if you are Chinese). One token after another >> in a sequence, as opposed to a map which needs two dimensins to make >> sense. >>
>
> Okay, I guess that allows parsers that look ahead and then retreat and
> possibly poetry too. I wonder what Codd was trying to disallow,
Off hand, I'd say the sort of ambiguity manifest in SQL: amorphous scope, references before declaration, &c.
> guessing perhaps it was a relational impl'n limited to the kind of
> multiple-parameter-idiosyncratic call interfaces he would have seen in
> IMS et al or maybe even QBE which had come out in the mid-1980's which
> was when I think his list appeared in the Computerworld flyer.
>
> p
Received on Fri Jun 23 2006 - 07:45:22 CEST