Hi, I've noticed that letrec seems to have a problematic expansion. I'm not sure if this has been discussed before (I couldn't find any matches):
csi> (macroexpand '(letrec ((x 1)) x)) (let ((g1312 (##core#undefined))) (begin (##core#set! g1312 (quote 1)) g1312)) This definition doesn't use temporaries -- as, for example, in the standard R5RS syntax-rules definition of letrec, http://www.schemers.org/Documents/Standards/R5RS/HTML/r5rs-Z-H-10.html#%_sec_7.3 Without using temporaries, some call/cc + letrec combinations don't work: (letrec ((x (call/cc list)) (y (call/cc list))) (if (procedure? x) (x (pair? y))) (if (procedure? y) (y (pair? x))) (let ((xk (car x)) (yk (car y))) (and (call/cc xk) (call/cc yk) (call/cc xk)))) csi produces #f, while SISC, Scheme48 and guile correctly output #t. Thanks go to Al Petrofsky for describing the problem. Dan Muresan http://alumnus.caltech.edu/~muresan/ _______________________________________________ Chicken-users mailing list Chicken-users@nongnu.org http://lists.nongnu.org/mailman/listinfo/chicken-users
