Sorry, I misclicked "send" when I wanted to further edit my e-mail ...
My Guile version is: ~~~~ (version) $6 = "3.0.4" ~~~~ On 20.09.20 14:16, Zelphir Kaltstahl wrote: > > Hello Guile users, > > I just noticed something weird about eq?. > > My Guile version is: > > > I get the different results, depending on whether I define some > bindings in a let or using define: > > (In Emacs Geiser:) > > ~~~~ > (define x '(10 9)) > (define y '(10 9)) > (eq? x y) > $2 = #f > > (let ([x '(10 9)] > [y '(10 9)]) > (eq? x y)) > $3 = #t > ~~~~ > > Is this intentional or a bug? > > I first noticed something strange when writing the following code: > > ~~~~DEFINITION~~~~ > (define make-multiple-list-remover > (λ (equal-proc) > (λ (lst unwanted) > (let loop ([remaining-list lst]) > (cond > [(null? remaining-list) > '()] > [(equal-proc (car remaining-list) unwanted) > (loop (cdr remaining-list))] > [else > (cons (car remaining-list) > (loop (cdr remaining-list)))]))))) > ~~~~ > > ~~~~TEST~~~~ > (let ([a '(9 10)] > [b '(9 10)]) > (test-equal "make-multiple-list-remover-03" > `(1 2 (3) (4) ,a) > ((make-multiple-list-remover eq?) > `(a b (c) (d) ,a) b))) > ~~~~ > > I was wondering, why the test fails. I think (eq? ...) should not be > able to see the equivalence of both lists a and b, just like when > defined using (define ...). > > I can also run it in the REPL and see the difference: > > ~~~~ > (define a '(9 10)) > (define b '(9 10)) > ((make-multiple-list-remover eq?) > `(a b (c) (d) ,a) b) > $4 = (a b (c) (d) (9 10)) > > (let ([a '(9 10)] > [b '(9 10)]) > ((make-multiple-list-remover eq?) > `(a b (c) (d) ,a) b)) > $5 = (a b (c) (d)) > ~~~~ > > Somehow the bindings of let seem to be different from the bindings > created using define. What about using define inside let? > > ~~~~ > > ~~~~ > -- > repositories: https://notabug.org/ZelphirKaltstahl Somehow the bindings of let seem to be different from the bindings created using define. What about using define inside let? ~~~~ (let ([unrelated 'bla]) (define a '(9 10)) (define b '(9 10)) ((make-multiple-list-remover eq?) `(a b (c) (d) ,a) b)) $7 = (a b (c) (d)) ~~~~ So there the define usage also differs from when I use define on the top level. Perhaps that is the difference? On which level the bindings are defined? Regards, Zelphir -- repositories: https://notabug.org/ZelphirKaltstahl
