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From: LANGFORD@VCUVAX.BITNET (Bob Langford)
Newsgroups: comp.os.vms
Subject: RE: checking for valid DCL commands.
Message-ID: <8706102225.AA09140@ucbvax.Berkeley.EDU>
Date: Tue, 9-Jun-87 09:18:00 EDT
Article-I.D.: ucbvax.8706102225.AA09140
Posted: Tue Jun  9 09:18:00 1987
Date-Received: Sat, 20-Jun-87 08:56:44 EDT
Sender: daemon@ucbvax.BERKELEY.EDU
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>    Is there a way to check whether a word is a logical or symbol (something
> like DIR*ECTORY or MAIL) without causing errors in DCL?  What I would like
> to do is check a parameter to see if it is a verb/symbol and $symbol if it is
> and $r parameter if it is not.

It is easy to see if a string is the name of a DCL symbol, but I don't know a
way to see if a string is a currently valid command.  However, it is easy to
do the reverse:  find out if the parameter string is the name of an image file.

$ X := f$parse(P2,".EXE")
$ if X .eqs. "" then $goto NoSuchProgram    ! hope it's a command....
$! Else, it is a program.
$ run 'X'         ! or RUN 'P2'

Hope this helps....

P.S.  There was a program called VERB on a past VAX Symposium tape from DECUS
that could extract a command verb definition from DCL's tables.  I suppose
it could be modified to check whether or not a verb is defined....


                              ...Bob...