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Re: Using empty_string as the only "" string

From: Juanma Barranquero
Subject: Re: Using empty_string as the only "" string
Date: Tue, 24 Apr 2007 23:54:00 +0200

On 4/24/07, Andreas Schwab <address@hidden> wrote:

In which way is this different from

   (eq (cdr '(a)) (cdr '(b))) => t

Well, that's non-optional, according to the Emacs Lisp documentation:
"Also, since symbol names are normally unique, if the arguments are
symbols with the same name, they are `eq'."

The doc also says: "For other types (e.g., lists, vectors, strings),
two arguments with the same contents or elements are not necessarily
`eq' to each other: they are `eq' only if they are the same object,
meaning that a change in the contents of one will be reflected by the
same change in the contents of the other."

So, as I said, it is an issue of object identity. I didn't say that
the results above would be "wrong", only surprising, and a noticeable
change in the current behaviour.


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