From:	SMTP%"dwing@uh01.Colorado.EDU" 19-DEC-1993 21:38:50.20
To:	EVERHART
CC:	
Subj:	Re: DEVINFO.COM - promised/requested, now delivered

X-Newsgroups: comp.os.vms
Subject: Re: DEVINFO.COM - promised/requested, now delivered
Message-ID: <1993Dec19.183608.549@buckie.hsc.colorado.edu>
From: dwing@uh01.Colorado.EDU (Dan Wing)
Date: 19 Dec 93 18:36:08 MDT
Reply-To: dwing@uh01.Colorado.EDU
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In article <18DEC199312502905@erich.triumf.ca>, music@erich.triumf.ca (FRED W. BACH) writes:
>  For safety's sake and to be more assured that things like your DCL script
> work properly, I usually add something like this to the top of my files:
>
> $SAY   = "WRITE SYS$OUTPUT"
> $EXIT  = "EXIT"
> $WRITE = "WRITE"
> $GOTO  = "GOTO"
> $IF    = "IF"
> $THEN  = "THEN"
> $ELSE  = "ELSE"
> $ENDIF = "ENDIF"
>
>   You might be surprised to find what some strange people re-define for
> standard DCL verb names.  In critical scripts that I write, I redefine
> every verb or symbol that I am going to use.  That way the users would have
> to foul up the DCL tables in order to sprong my programs.  Most of them
> don't know how. I have found that this approach of re-defining the verbs to
> be symbols pointing to real verbs is almost foolproof.
>
>   Your file needed the definition of "SAY".
>
>   Other folks may wish to set the symbol scope and then define explicitly
> what they want.   The above is just as good, I suppose.

That's a waste -- since VMS V5.0 you can simply do:

  $ SET SYMBOL/SCOPE=(noLOCAL,noGLOBAL)

which disables the .COM file's access to all local and global symbols -- it 
executes much faster than defining every single symbol you're going to use.

Widely-distributed .COM files, such as Andy Harper's VMS_SHARE, include
lines like:

  $ SET := SET
  $ SET SYMBOL/SCOPE=(noLOCAL,noGLOBAL)

which is the fastest and safest way of ensuring the symbols have their
"desired" meaning.

-Dan Wing, Systems Administrator, University Hospital, Denver
 dwing@uh01.colorado.edu or wing@eisner.decus.org