bug#64960: Documentation for copy-sequence

[Michael Heerdegen <michael_heerdegen@web.de>]

uzibalqa via "Bug reports for GNU Emacs, the Swiss army knife of text
editors" <bug-gnu-emacs@gnu.org> writes:

> > > When I modify the copy, the original remains intact.
> >
> >
> > No, if you modify an element of the copy, the corresponding element of
> > the original is also changed. That's what "shared" means.
>
> Except for strings

It is irrelevant what happens when you modify elements of a copied
string because it is impossible.  The statement is simply not applicable
to strings.  That's why the docstring only speaks of "list, vector or
record".

Note that substituting a character in a string is not the same as
modifying the character.  You are substituting a sequence element with
another one and not modifying an element in that case.

The same is true for the list (1 2 3) for example.  Exactly the same
situation as for a string: You can replace the number 2 in a copy with
another one but you can't modify the number 2 in the list.  Numbers and
characters are not mutable.

Michael.