Re: [Pika-dev] Problem with Pika's macro expander?

[Tom Lord]

    > From: Matthew Dempsky <address@hidden>

    > >           `(letrec "gtn" 
    > >               ,y... 
    > >               ,temp...
    > >               ,var1-init...
    > >               ,@ body...))

    > I think you actually meant (let bindings omitted):
    > 
    >           `(letrec "gtn" 
    >               ,y... 
    >               (,_newtemp_ ,@temp...)
    >               ,var1-init...
    >               ,@ body...))

Right.

    > Also, for the record, I'd like to point out that there should be just
    > one call to hygenic-binding-of per symbol when expanding a
    > syntax-rules clause.  For example, the following clause is part of the
    > R5RS syntax-rules definition of OR:
    > 
    >     ((or test1 test2 ...)
    >      (let ((x test1))
    >        (if x x (or test2 ...))))

    > It's important to expand that into:
    > 
    >     (let ((test1    (cadr exp))
    >           (test2... (cddr exp))
    >           (_let     (hygenic-binding-of let))
    >           (_x       (hygenic-binding-of x))
    >           (_if      (hygenic-binding-of if))
    >           (_or      (hygenic-binding-of or)))
    >         `(,_let ((,_x ,test1))
    >            (,_if ,_x ,_x (,_or ,@test2...))))

    > rather than:

    >     (let ((test1    (cadr exp))
    >           (test2... (cddr exp))
    >           (_let     (hygenic-binding-of let))
    >           (_x1      (hygenic-binding-of x))
    >           (_x2      (hygenic-binding-of x))
    >           (_x3      (hygenic-binding-of x))
    >           (_if      (hygenic-binding-of if))
    >           (_or      (hygenic-binding-of or)))
    >         `(,_let ((,_x1 ,test1))
    >            (,_if ,_x2 ,_x3 (,_or ,@test2...))))


    > I doubt the above would be a likely expansion that anyone would
    > generate, but equivalent semantics might be formed by a naive
    > implementation.

Right.

-t