[plt-scheme] Re: Poacher turned gamekeeper

"instead of crashing when a non-number string is given, return a special
value that says there is something wrong" ?
That may be an introduction to error-handling, which is a big part of
programming?

On Thu, Nov 12, 2009 at 12:42, wooks <wookiz at hotmail.com> wrote:

>
>
> On Nov 12, 11:32 am, "Geoffrey S. Knauth" <ge... at knauth.org> wrote:
> > On Nov 12, 2009, at 05:44, wooks wrote:
> >
> > > On Nov 9, 2:50 pm, Matthias Felleisen <matth... at ccs.neu.edu> wrote:
> > >> 1. Use HtDP/2e to get started. Then switch.
> > > So I'm looking at it and wondering how to explain why (string->number
> > > "hello world") returns a boolean.
> >
> > My documentation for beginner language says:
> >
> > string->number : (string -> (union number false))
> >
> > Purpose: to convert a string into a number, produce false if >impossible
> >
>
> Yes I saw that. I was hoping be able to give a different answer than
> "thats the way it was defined".
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