[plt-scheme] question about eval in macro

Aren't you mean

(define-syntax s (syntax-rules () ((_ x) (eval 'x))))

(s '#0=(1 . #0#))

? It works fine.

Chongkai


Jos Koot wrote:
> Who can help me understand the following two ???s ?
>  
> (eval ''#0=(1 . #0#)) ; --> #0=(1 . #0#) ; ok
> (define s (syntax-rules () ((_ x) (eval 'x))))
> ;(s '#0=(1 . #0#)) --> bug ?: bad syntax in: #0=(1 . #0#) ; ???
> ;(s ''#0=(1 . #0#)) --> bug syntax-source: expects argument of type 
> <syntax>; given '#0=(1 . #0#) ; ???
>  
> (define-syntax t (syntax-rules () ((_ x) (eval `x))))
> ;(t '#0=(1 . #0#)) ; never returns ; ok, because quasiquote allocates 
> and looks inside the circular list for unquote
> (t ,''#0=(1 . #0#)) ; --> #0=(1 . #0#) ; ok
> (t ','#0=(1 . #0#)) ; --> #0=(1 . #0#) ; ok
>  
> Is this a bug or am I missing some profound understanding?
> I know that the use of eval is not encouraged, but I need it in my own 
> test system (allowing multiple values, checking standard output and 
> checking for the correct error messages when expected)
> Thanks, Jos koot
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