Reader handling of the @ character

[Duncan Mak <duncanmak@gmail.com>]

Hello all,

I'm playing with the Alex Shinn match.scm macro again and I noticed that it
doesn't load in Kawa,

I think it's failing because of the handling of the @ character, probably
due to how the splice operator was implemented.

I tried the following in Chez, this is what I see with this test
syntax-rules macro:

$ chez
Chez Scheme Version 9.5.2
Copyright 1984-2019 Cisco Systems, Inc.
> (define-syntax test
    (syntax-rules (@)
      ((test @ x y z) (list x y z))))
> (test @ 1 2 3)
(1 2 3)
> (test 1 2 3)
Exception: invalid syntax (test 1 2 3)
Type (debug) to enter the debugger.
>


The same macro doesn't work in Kawa 3.1.1:

$ kawa
#|kawa:1|# (define-syntax test
#|.....2|#   (syntax-rules (@)
#|.....3|#     ((test @ x y z) (list x y z))))
#|.....4|#
/dev/tty:2:20: invalid character #\)
#|kawa:5|# (test @ 1 2 3)
/dev/tty:5:2: warning - no declaration seen for test
/dev/tty:5:2: unbound location: test
at gnu.mapping.DynamicLocation.get(DynamicLocation.java:36)
at atInteractiveLevel-2.run(tty:5)
at gnu.expr.ModuleExp.evalModule2(ModuleExp.java:290)
at gnu.expr.ModuleExp.evalModule(ModuleExp.java:211)
at kawa.Shell.run(Shell.java:289)
at kawa.Shell.run(Shell.java:196)
at kawa.Shell.run(Shell.java:183)
at kawa.repl.processArgs(repl.java:724)
at kawa.repl.main(repl.java:830)

-- 
Duncan.