Re: Optional Arguments (was Re: CVS script)

[Tim Pierce <twp@skepsis.com>]

> > However, if, say, #f
> > were the false value and #f\ were the character `f',
> 
> Well, we only need to distinguish #!/ and #! followed by letter.

If I'm not mistaken, the canonical magic cookie for a script
interpreter is `#! /', with a space, i.e.:

	    #! /usr/bin/perl -w

So we'd want to handle that case as well.

I'm unhappy with all of the conventions I've seen for handling this
matter.  It feels as if we've painted ourselves into a corner.  To my
knowledge, no other scripting language in common use requires any
special syntax for #! interpolation, such as the #! ... !# block
comment syntax introduced by SCSH.  That kind of means that our
current convention is a wart.

I'd be more comfortable if we could adopt something like:

	#! as the first two characters in a file represent
	a comment until end-of-line.

... with some appropriate backward compatibility to handle the #! ... !#
syntax that we presently use.  Then we could adopt the same
argument-processing mechanisms as existing Unix interpreters.  I think
that if we make the script invocation much more complex than this, it
will discourage people from using Guile -- it's a minor inconvenience,
but feels very unwieldy.

I don't have any strong opinion about how #! should be handled
elsewhere in a Guile program.  It would be nice if we could invent
some meaning that would be consistent throughout the language, but I
prefer scripting convenience to consistency for this case.

These comments need to be tempered by the fact that I haven't had time
to do anything with Guile for about six months, so I am basically
providing opinions without doing anything useful about them.  Sorry
about that.

-- T.

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