[Scheme-reports] command-line and invocation manner

[Per Bothner <per@x>]

The command-line procedure doesn't distinguish between what we
might call "application arguments" (arguments meant for the
application) and "invocation arguments" (the command and argument
for starting up Scheme with a given "application").

For example, suppose I have foo.scm containing:
(format #t "c-l: ~w~%" (command-line))

One might load this file using load, run it from the command line,
or compile it and then execute it.  I think one would want the application
arguments to be the same regardless.  The choice I made for Kawa
was that the application arguments are (cdr (command-line))
while the invocation arguments are pasted to a single string as
the (car (command-line)).  I think this is allowed by R6RS/R7RS,
and I think this is a reasonable approach.

Examples:

$ java kawa.repl ~/tmp/foo.scm abc "def ghi"
c-l: ("java kawa.repl /home/bothner/tmp/foo.scm" "abc" "def ghi")

(kawa.repl is the main "driver" application class for kawa.)

The "kawa" program is a front-end with readline support that
connects to an inferior JVM.  Using it results in:

$ kawa ~/tmp/foo.scm abc "def ghi"
c-l: ("java kawa.repl --connect 44549 /home/bothner/tmp/foo.scm" "abc"
       "def ghi")

Using load:

$ java kawa.repl -e '(load "/home/bothner/tmp/foo.scm")' abc "def ghi"
c-l: ("java kawa.repl -e (load \"/home/bothner/tmp/foo.scm\")" "abc" 
"def ghi")

The -f flag enable line-by-line loading (rather than module-at-at-time
loading), but for many cases it works the same:

$ java kawa.repl -f ~/tmp/foo.scm abc "def ghi"
c-l: ("java kawa.repl -f /home/bothner/tmp/foo.scm" "abc" "def ghi")

Compiling as class run by the kawa.repl driver (or kawa front-end):

$ kawa -C ~/tmp/foo.scm
(compiling /home/bothner/tmp/foo.scm to foo)
$ java kawa.repl foo abc "def ghi"
c-l: ("java kawa.repl foo" "abc" "def ghi")
$ kawa foo abc "def ghi"
c-l: ("java kawa.repl --connect 45671 foo" "abc" "def ghi")

Compiling to an application (with a static "main" method):

$ kawa --main -C ~/tmp/foo.scm
(compiling /home/bothner/tmp/foo.scm to foo)
$ java foo abc "def ghi"
c-l: ("java foo" "abc" "def ghi")

All yield the same (cdr (command-line)), but the (car (command-line))
depends on how it was invoked.
-- 
	--Per Bothner
per@x   http://per.bothner.com/

_______________________________________________
Scheme-reports mailing list
Scheme-reports@x
http://lists.scheme-reports.org/cgi-bin/mailman/listinfo/scheme-reports