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Re: Several comments

This page is part of the web mail archives of SRFI 22 from before July 7th, 2015. The new archives for SRFI 22 contain all messages, not just those from before July 7th, 2015.

> Marc Feeley <feeley@xxxxxxxxxxxxxxxx> writes:
> >   #! /bin/sh
> >   "exec" "scheme-script" "$0" "$@"
> >   (define (main arg1 arg2)
> >     (write (+ (string->number arg1) (string->number arg2))))
> >   (apply main (command-line-arguments))
> I prefer this approach.  I think it is more compatible with the
> traditional "load".
> The Kawa compiler can take this kind of script, and if you compile
> it with --main you get a stand-alone Java application.  If you load
> it, you get the behavior expected of the script. I don't think the
> rationale for easier debugging is strong enough to compensate for
> a clumsier and less traditional interface.
> I think "script-arguments" is not a good name.  What is a "script"?
> Why the word "script" as apposed to "program" or "application"?
> "command-line-arguments" is both more descriptive and avoids the
> "script" vs "program" issue.  It is so descriptive that both Scsh
> and Kawa use it - but they use it for a global variable.  Using it
> for a function would clash.  Scsh does have "(command-line)" which
> returns the complete command line, including the name the script
> was executed as.

I introduced the name "script-arguments" to distinguish it from the
name "command-line-arguments" I used in previous examples (and in fact
in the example you quote above).  The call (command-line-arguments)
always returns the list of command line arguments.  I introduced
(script-arguments) to have a different meaning when executed in the
dynamic extent of a "load" (i.e. an error).  Although I am open to
different names, I think it is important in this case that "script"
appear in the name to highlight that it should only be used in a

You could define

  (define (script-arguments)
    (if (in-the-dynamic-extent-of-a-load?)
        (error "Attempt to load a script in an inappropriate context")

I'm don't know the rationale for Scsh's use of a global variable for
"command-line-arguments", but I don't like such an interface (I prefer
to hide the information behind a function so that the behaviour can be
changed more easily).