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From: tedcrane@batcomputer.UUCP
Newsgroups: comp.os.vms
Subject: Re: Contemplations on CDU
Message-ID: <1299@batcomputer.tn.cornell.edu>
Date: Mon, 8-Jun-87 14:34:31 EDT
Article-I.D.: batcompu.1299
Posted: Mon Jun  8 14:34:31 1987
Date-Received: Thu, 11-Jun-87 01:55:15 EDT
References: <8706060828.AA10670@ucbvax.Berkeley.EDU>
Reply-To: tedcrane@tcgould.tn.cornell.edu.UUCP (Ted Crane)
Distribution: world
Organization: Program of Computer Graphics, Cornell University
Lines: 38

In article <8706060828.AA10670@ucbvax.Berkeley.EDU> SLOANE@UKANVAX.BITNET (BOB) writes:
>Erland Sommarskog, ENEA Data, Stockholm gives the following CLD example:
>   Define type DESCRIPTION_WORDS
>       Keyword HEADER  default, nonnegatable, value(default=0)
>       Keyword FOOT    default, nonnegatable, value(default=0)
>       Keyword PAGE    default, nonnegatable, value(default=0)
>   ...
>   Qualifier DESCRIPTION
>             Default,
>             Nonnegatable,
>             Value(Required, List, Type = DESCRIPTION_WORDS)
>.....
>It seems to me that HEADER, FOOT and PAGE are VALUES that the /DESC
>qualifier can have.  As such, I doubt that the DESC qualifier should
>take on more than one value by default.  What you really have is 3
>different qualifiers here, not just one qualifier that can take different
>values.  Users not only have to remember the FOOT, HEADER, and PAGE values
>but also the /DESC Qualifier.  If I were using a program with this syntax
>I would rather just remember 3 things, not 4. It seems to me that the DESC
>qualifier is redundant and could be eliminated.

Bob expresses a point of view that many folks agree with.  However, I have
run up againast a few cases where the opposite is true.  The best example
uses the good ol' DCL command, DIRECTORY.

Right now, DIRECTORY has a large number of qualifiers whose purpose in life
is to select files based on some criteria.  For example, "/SINCE", "/OWNER_UIC",and the like.  There is also one whose syntax is actually:
	/SELECT = SIZE={MIN,MAX} [=size]
In the case of qualifiers which "select", then wouldn't it be more
obvious to say
	/SELECT=(SIZE=something,DATE=SINCE=something,OWNER=something)
in other words, to group all the selections?

Similarly, to group all the display items?
	/DISPLAY=(filename,size,creation_date....)

Well, anyway, there are two ways to look at it.  In some cases a hierarchical
approach as suggested in the original article is appropriate.