About 'quote'

About 'quote'

[self]

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scheme@(guile-user)> (eq? 'abc 'abc)
$1 = #t
scheme@(guile-user)> (eq? '(+ x 1) '(+ x 1))
$2 = #f

why $1 is true and $2 is false?
when I looked for 'quoting' in the r6rs
 I found it:
Different constants that are the value of aquote expression may share the same locations

I think:
'abc ' is a constant, so the first 'abc  eq the second 'abc,
and what about (+ x 1)?
I missing about how 'quote' act on non-constant?
my english is poor, sorry to that

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Re: About 'quote'

[Andy Wingo]

On Fri 10 Dec 2010 12:22, self <lispor@163.com> writes:

> scheme@(guile-user)> (eq? 'abc 'abc)
> $1 = #t
> scheme@(guile-user)> (eq? '(+ x 1) '(+ x 1))
> $2 = #f
>
> why $1 is true and $2 is false?
> when I looked for 'quoting' in the r6rs
>  I found it:
> Different constants that are the value of a quote expression may share the same locations

*May* is the crucial word here.  May, but not *must*.  Implementations
are free to allocate identical quoted lists in the same place, or in
different places.  If they are in different places, they are not eq?.

Andy
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