On Thu, 17 Mar 2016 13:08:44 -0500,
Arnel wrote:
>
> Hi,
>
> How does 'string-join' differ from 'string-append'? More specifically, why
> does
> the following code:
>
> (let ([z ""]
> [y "b"])
> (string-join '(z y) "\n"))
>
> result in a contract violation, yet the following:
>
> (let ([z ""]
> [y "b"])
> (string-append z y))
>
> works without any issues. (It's not necessarily the result I wanted, but I can
> work around it.) Isn't '(z y) essentially a list of strings?
'(z y) is not a list of strings. It's a list with two symbols, 'z and 'y.
(list z y) will be a list with the two strings you want.
The quote form does create a list in this case, but it does not evaluate
any of its subforms. Hence why you get symbols, as opposed to the values
of your variables.
Vincent
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