macroexpand and nested syntax-rules about lips

[jcubic]

This is actually a collision of _ binding that is used in nested syntax-rules. It works as code but fail when expanding.

(define-syntax symbol
  (syntax-rules ()
    ((_ name)
     (let-syntax ((name (syntax-rules ()
                       ((_)
                        (list 'name)))))
       (name)))))

(print (symbol hello))
;; ==> (hello)
(pprint (macroexpand (symbol hello)))
;; ==> syntax-rules: no matching syntax in macro (symbol)

[jcubic]

It's not a collision only macroexpand try to evaluate (symbol) inside pattern of syntax-rules.

This is the problem that macroexpand know nothing about nested syntax-rules. That's why they don't expand at all.