[plt-scheme] Re: Poacher turned gamekeeper

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