Re: [racket] lambda as default value to dict-ref

[mailto:users-boun...@racket-lang.org] On Behalf Of J G Cho Sent: sábado, 16 de febrero de 2013 3:55 To: Racket mailing list Subject: [racket] lambda as default value to dict-ref So, I have a dict A that looks like (list ("string as key" . (lambda (arg) ...) ...) I do ((dict-ref A key (lambda

Re: [racket] lambda as default value to dict-ref

If the third argument to `dict-ref' (and `hash-ref') is a function, then the function is called as a failure thunk. If the third argument is any other kind of value, then the value is returned as the result in case of failure. This is convenient but, yes, potentially confusing. If you want a defa

[racket] lambda as default value to dict-ref

So, I have a dict A that looks like (list ("string as key" . (lambda (arg) ...) ...) I do ((dict-ref A key (lambda (_) "wrong key")) some-params). When keys are valid the above work as expected. When the key does not find any, I was expecting ((lambda (_) "wrong key") some-params) but it fails w