Yes, of course it is and that first branch executes and thus the error in the second branch (now a runtime error, thanks to the repl), is not signaled.
Robby On Fri, Jun 8, 2012 at 11:01 AM, Matthias Felleisen <[email protected]> wrote: > > With all due respect, I disagree. Like Jens, I consider the (define u ..) > nested and scoped inside the first cond branch. > > > On Jun 8, 2012, at 11:56 AM, Sam Tobin-Hochstadt wrote: > >> On Fri, Jun 8, 2012 at 11:42 AM, Jens Axel Søgaard >> <[email protected]> wrote: >>> >>> When >>> >>> (let ([x 1]) >>> (cond >>> [(= x 1) >>> (define u 2) >>> (+ u 1)] >>> [else u])) >>> >>> is pasted into the interaction window, I get 3 ! >>> >>> I was expecting an error. >> >> This is the same behavior as: >> >> -> (if #f x 1) >> 1 >> >> What's happening is that `#%top` behaves differently at the REPL than >> in a module. This enables you to write: >> >> -> (define (even? x) (or (zero? x) (odd? (sub1 x)))) >> -> (define (odd? x) (or (= x 1) (even? (sub1 x)))) >> >> without getting an error when entering the first line. >> -- >> sam th >> [email protected] >> >> ____________________ >> Racket Users list: >> http://lists.racket-lang.org/users > > > ____________________ > Racket Users list: > http://lists.racket-lang.org/users ____________________ Racket Users list: http://lists.racket-lang.org/users
