Hi,
I'm trying to get a working understanding of macros (I don't
know if I'll every really understand them -- I'm trying).
I understand that DATUM->SYNTAX gets it's context
information from it's first argument. I have no problems
when using simple (non-ellipses) pattern variables, however,
I haven't been unable to get a strictly "ellipses pattern"
to work in this context (no pun intended). As a
work-a-round I came up w/ passing in a dummy symbol to use
as the first argument but would like to find out how to do
it the correct way.
First my work-a-round : (works)
(define-syntax test-this
(lambda (x)
(syntax-case x ()
[(_ ctx a ...)
(with-syntax
([form (datum->syntax (syntax ctx)
`(+ ,@(syntax->datum (syntax (a ...)))))])
(syntax form))])))
(let*-values
([(one two three) (values 10 20 30)])
(test-this '* one two three))
I've tried this but it does not work :
(define-syntax test-this
(lambda (x)
(syntax-case x ()
[(_ a ...)
(with-syntax
([form (datum->syntax (syntax (a ...))
`(+ ,@(syntax->datum (syntax (a ...)))))])
(syntax form))])))
(let*-values
([(one two three) (values 10 20 30)])
(test-this one two three))
as it comes back with the error message :
compile: unbound identifier in module in: one
Any help would be much appreciated.
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