drscheme

[ddatta8]

I am trying to execute the code (append '(a b) '(c d)) in drscheme using lazyscheme and I am getting the following output: (a . #<promise:...cts/lazy/lazy.ss:453:38>). What is the problem? Thanks.

[Crosson]

Append is only for appending an element to a list, not for joining two lists.

[ddatta8]

Thanks but even if I do (append 'a '(c d)) /(append '(a b) 'c),
I get the following error messages:
. . car: expects argument of type <pair>; given a/(a . #<promise:...cts/lazy/lazy.ss:453:38>)

[Crosson]

Sorry, I am not familiar with the lazyscheme dialect; I didn't realize it had a different version of append.