[plt-scheme] Perplexed Programmers

>
> No! What you could do is -- say after three or four weeks -- have
> students spell out the structure of the data with code:
>
>  (define-data List-of-numbers
>    empty
>    (cons Number List-of-numbers)))
>
> and annotate functions with input types:
>
>  (define: (f {l : List-of-numbers})
>    (cond
>      [(empty? l) ...]
>      [(cons? l) ... (first l) ... (f (rest l)) ...]))
>

Just a related inquiry. This typing discipline has its benefits as is
routinely discussed on this list. The benefits of dynamic typing,
however, seem to receive little attention. When do readers of this
list suggest introducing the notion of dynamic typing?

Cheers,

Marco