Am 07.09.2005, 06:58 Uhr, schrieb Dmitry Lizorkin <[EMAIL PROTECTED]>:
Hello!
I am not quite familiar with Chicken macro system, and I cannot
understand
the following result:
[...]
Could you please explain this result to me? What should I do in order to
escape the # character in identifiers?
[...]
Hello,
this problem has got nothing to do with CHICKEN's macro system. It just
means that there is a considerably larger amount of magic involved with
qualified symbols and keywords in CHICKEN, which is not documented at all.
To get the keyword blubb: you would have to do something like
(string->symbol "\x00blubb")
and to get the qualified symbol ##sys#structure? you would have to do
(string->symbol "\x03sysstructure?")
So the magic is actually in the first byte of the symbol's name!
Therefore, to achieve your goal you should use a macro like this:
(define-macro (qualified-symbol namespace symbol)
(let* ((ns (symbol->string namespace))
(nsl (string-length ns))
(sm (symbol->string symbol)))
(if (or (fx< nsl 1) (fx> nsl 31))
(abort
(make-composite-condition
(make-property-condition
'exn
'message "namespace identifier too short or too long"
'location 'qualified-symbol
'arguments (list namespace symbol))
(make-property-condition
'syntax))))
(string->symbol
(string-append
(string (integer->char nsl))
ns sm))))
Perhaps a string->qualified-symbol procedure along these lines should be
added to CHICKEN for completeness' sake?
Ciao,
Thomas
_______________________________________________
Chicken-users mailing list
[email protected]
http://lists.nongnu.org/mailman/listinfo/chicken-users
