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From: ok@goanna.cs.rmit.oz.au (Richard A. O'Keefe)
Newsgroups: comp.lang.fortran
Subject: Re: Command line arguements?
Message-ID: <6054@goanna.cs.rmit.oz.au>
Date: 31 May 91 08:22:19 GMT
References: <eesnyder.675543629@beagle> <24632@lanl.gov> <24713@lanl.gov>
Organization: Comp Sci, RMIT, Melbourne, Australia
Lines: 65

In article <24713@lanl.gov>, jlg@cochiti.lanl.gov (Jim Giles) writes:
> As I said above, the _shell_ processes the command line before I get to
> look at it.  So, getarg() and iargc() don't give me the arguments that
> the user typed, they give me the _processed_ arguments.  This means that
> my command line syntax has to avoid quotes, backslashes, wildcard characters,
> and probably a few other things.

Yes and no.  It is not the case that every program is invoked from 
``the'' shell (do you mean sh, csh, tcsh, ksh, bash, rc, tcl, or what?).
It may be that there never *was* any such thing as a line typed by
``the user''.  Your command line syntax, if it uses any of the usual
meta-characters {}[]()<>,;$\'", will need quoting, but the only character
which is actually forbidden to you is NUL.

> If the shell passed the _unprocessed_ command line _in_addition_ to the
> parsed argument list (either as another argument to main() or as an
> environment variable) then I could design code which used any command 
> line syntax I wanted.

Improved Giles-specific shell:

	while read line ; do
	    export COMMAND_LINE
	    COMMAND_LINES="$line"
	    eval "$line"
	done

> In particular, I could apply the same wildcard 
> and quoting conventions to alternative search spaces - not just to local
> file names.

Not quite.  You would have to program them yourself.  UNIX shell
wild-cards are specialised to file names (for example, none of them
will match a '/').  If the things you want to match against aren't
file names (as in your phone book example), that may not be appropriate.
My equivalent of 'phone' expands to a call to Awk, and the pattern
matching provided by Awk is not identical to shell file name wildcards.

> For example, I could have a phonebook program that listed
> phone numbers for people specified as:
> 
> cochiti => phone s*m S*de
> 
> Which would find (say) Sam Spade and print his number.  It would also 
> find Slim Shade, etc.. You get the picture.  At present, the only ways
> to do this are to require the user to quote the patterns to get them
> past the shell or to make the utility interactive: ignore the command
> line and ask for the name interactively.

Well, you _could_ do
	phone <<'.'
	s*m S*de
	.

I've used TOPS-10 (where you _only_ get an uninterpreted command line)
and VM/CMS (where you can get both a tokenised and an uninterpreted
command line), and for that reason I very much like the approach taken
by the UNIX shells.  This divergence in the interfaces offered by
various operating systems is of course why "get command line arguments"
is not a standard feature of Fortran.

-- 
Should you ever intend to dull the wits of a young man and to
incapacitate his brains for any kind of thought whatever, then
you cannot do better than give him Hegel to read.  -- Schopenhauer.