On 2012-02-29 19:14:48 +0100, ROELOF WOBBEN wrote:
> ;String -> String
> ;This function takes out the first character of a given string with the
> name s
> ; given "roelof" expect "r"
> ; given "example" expect "e"
> (define (string_first s)
> (if (eq? (string? s) true)
> (string-ith* s 0 )
> "You have not entered a string"))
> [Ed: reformatted]
>
> So I hope somone can give me feedback on my first attempt so i can learn
> from it.
A couple of comments:
* `string-first` (- instead of the _) is a more idiomatic naming
* (eq? (string? s) true) is verbose. (string? s) already returns a
boolean.
* Generally, when writing programs using the design recipe you don't
need to think of the error cases (e.g., when the contract is
violated) like `s` not being a string. You may want to think of some
edge cases though (how long can a string be?).
Cheers,
Asumu
____________________
Racket Users list:
http://lists.racket-lang.org/users
