Article View: comp.lang.prolog
Article #3113Re: BSI Proposal
From: Micha Meier
Date: Thu, 17 Mar 1988 12:06
Date: Thu, 17 Mar 1988 12:06
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2387 bytes
In article <771@cresswell.quintus.UUCP> ok@quintus.UUCP (Richard A. O'Keefe) writes:
>As Chris Moss says, most languages since Fortran regard blanks as
>significant. Surely it is inconsistent to argue that
> "RED O" and "REDO"
>are different, and that is a Good Thing, but
> "red (O)" and "red(O)"
>being different is a Bad Thing? Blanks are being treated as
>significant in both cases. "RED O" and "red (" are both two tokens,
>and "REDO" and "red(" are both one token; it's exactly the same thing.
>What's sauce for the goose is sauce for the gander.
I'm no fan of the allowed space between the functor and
the opening parenthesis, but this does not seem to me as
a good argument. In the usual languages blankspaces are
allowed between characters of different classes (in the POP
meaning of character classes), with some exceptions like
e.g. the floating point constants. From this point of view
a space between "red" and "(" seems rather natural,
to say that "red(" is one token seems to me at least arguable
(easy to implement, I admit).
But there are other consequences of this BSI rule - is there any
reasonable argument to forbid binary operators that start with
a capital letter or that contain letters and graphic chars?
Actually, we have implemented the BSI standard in our Sepia,
(it's probably one of the first implementations)
but I have to admit that one of the first things to provide
was a switch to be able to switch it off. There is a long list
of problems we have encountered, we are going to pass them to
BSI soon. I have appreciated to have a minimal list of
built-ins provided by BSI, but the description contains so
many errors that one has really to take care when implementing
them. My global impression from BSI is, I'm afraid, close
to that of R.A.O'K, it is a new language, and very
difficult to implement. I've never really understood the grammar
and the 'Formal Specification of Prolog', though :-)
--Micha
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Path: arc1-ca.pugleaf.net!utzoo!mnetor!uunet!mcvax!unido!ecrcvax!micha From: micha@ecrcvax.UUCP (Micha Meier) Newsgroups: comp.lang.prolog Subject: Re: BSI Proposal Message-ID: <517@ecrcvax.UUCP> Date: 17 Mar 88 12:06:38 GMT References: <229@gould.doc.ic.ac.uk> <771@cresswell.quintus.UUCP> Reply-To: micha@ecrcvax.UUCP (Micha Meier) Organization: ECRC, Munich 81, West Germany Lines: 39