[racket] Confused between strings and symbols
Bo,
The quote form wraps fully-evaluated data, so let's peel away the quote
around the result and see what you have:
(this (is silly))
In quoted data, parentheses mean a list. So you have a list of two
elements:
this
(is silly)
The first element is a symbol. The second is a list of two further
elements:
is
silly
Those are also symbols. If you want to explore this stuff yourself, you
can always use the built-in predicates in Racket:
(define x (list 'this '(is silly)))
(string? x)
(symbol? x)
(list? x)
(define y (first x))
(define z (second x))
(string? y)
(symbol? y)
(list? y)
... and so on. I don't know if this answers all your questions, but
hopefully being able to explore this stuff yourself will get you a few
steps further.
Carl Eastlund
On Sun, Oct 27, 2013 at 4:23 PM, Bo Gus <forumangus at gmail.com> wrote:
> If I evaluate this:
>
> (list 'this '(is silly))
>
> I get this:
>
> '(this (is silly))
>
> I just want to check I understand what is happening here.
>
>
> list always returns a proper list hence I see no dotted notation here.
>
> The return value is quoted which means it is a symbol? But there are
> spaces so can it be a symbol? And in addition, list returns a proper list
> so it is a list? A symbolic list?
>
> Or does the quote in returned just mean it is string data in the list?
>
> The nested parentheses around is silly is indicating that this is a inner
> list - a list within a list? What is in the inner list? Two strings? One
> string made up of the characters i, s, space, s, i, l, l, y ?
>
> I suppose the thing that confuses me the most is the idea of a symbol.
> There are no quotes around the textual information in the returned data so
> do I assume the text is not string data? If so are they symbols?
>
> Please help clarify.
>
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