[Scutigena-code] Re: mzscheme command line options

[<da...@de...>]

The following message is a courtesy copy of an article
that has been posted to comp.lang.scheme as well.

Jens Axel Søgaard <jen...@so...> writes:

> David N. Welton wrote:

>  > [ Please CC replies to me - thanks! ]

> That's against etiquette. If people send the answer directly to you,
> then later people having the same problem can't find the answer in
> the archives.

I would agree with you had I asked you to respond directly to me, but
I only asked the courtesy of a CC so as to make my life a bit easier.
Most newsreaders let you do that quite easily.

>  > I have a question about mzscheme's processing of command line
>  > options. I'm using this code:

>  > (define (main args) (display "hello world") (newline))

>  > and trying to run it like so:

>  > VERSION 205:
>  > @eugene [~] $ mzscheme -f hello.mzscheme -v -C hello.mzscheme 1
>  > hello world

>  > VERSION 203:
>  > @ashland [~] $ mzscheme -f hello.mzscheme -v -C hello.mzscheme 1
>  > Welcome to MzScheme version 203, Copyright (c) 1995-2002 PLT
>  > hello world(hello.mzscheme 1)

> Are you sure the contents of hello.mzscheme is the same at eugene
> and ashland?

Positive, but I'm willing to change the contents to achieve my goal.

>  > But even worse:

>  > 203:
>  > @ashland [~] $ mzscheme -f hello.mzscheme -v -C 1
>  > Welcome to MzScheme version 203, Copyright (c) 1995-2002 PLT
>  > hello world(1)

>  > 205:
>  > @eugene [~] $ mzscheme -f hello.mzscheme -v -C 1
>  > default-load-handler: cannot open input file: "/home/davidw/1" (No such file or directory; errno=2)


> Try moving the -C switch:

>    @eugene [~] $ mzscheme -C hello.mzscheme foo bar

Fails in 203:

@ashland [~] $ mzscheme -C hello.mzscheme foo bar
Welcome to MzScheme version 203, Copyright (c) 1995-2002 PLT
reference to undefined identifier: main
>

> The explanation of -C in mzscheme 205 is:
>    -C, --main : Like -r, then call `main' w/argument list; car is file name.
>    -r, --script : Script mode: use as last switch for scripts. Same as -fmv-.

> Since -fmv- is short for -f -m -v -- and in particular contains -f
> which is followed by a filename, the name after -C (namely 1) is
> interpreted as a filename, and mzscheme will try to load it,
> resulting in the above errror.

Sure, that makes sense, but it's a pity that it is not consistent
between the two versions.

>    -f <file>, --load <file> : Loads <file> after MzScheme starts.
>    -- : No argument following this switch is used as a switch.
>    -m, --mute-banner : Suppresses the startup banner text.
>    -v, --version : Suppresses the read-eval-print loop.

> The best solution is to upgrade mzscheme to version 205.

I can do that when it arrives Debian testing.

> If you can't get the same switches to work in both versions, then
> put this in hello.mzscheme :

>    (define (main args)
>      (display "Hello World")  (newline)
>      (display args)           (newline))

>    (main (vector->list (current-command-line-arguments)))

> and start it with

>     mzscheme -v -m -f hello.mzscheme -- foo bar

Beautiful!  That's what I was after, thankyou:-)

-- 
David N. Welton
   Consulting: http://www.dedasys.com/
     Personal: http://www.dedasys.com/davidw/
Free Software: http://www.dedasys.com/freesoftware/
   Apache Tcl: http://tcl.apache.org/