Re: Why isn't the string returned by symbol-name read-only?

[Chong Yidong <cyd@stupidchicken.com>]

Daniel Colascione <daniel@censorshipresearch.org> writes:

> Consider
>
> (let ((name (symbol-name 'foo)))
>   (aset name 0 ?x)
>   (cons name (symbol-name 'foo)))
>
> That yields ("xoo" . " xoo")
>
> Now try
>
>
> (let ((name (symbol-name 'car)))
>   (aset name 0 ?x)
>   (cons name (symbol-name 'car)))
>
> That returns in an error when you try to evaluate it. The object
> returned by (symbol-name 'car) must have some read-only bit set.
>
> Why isn't that bit set for *all* symbol names?

Users will always have enough rope to hang themselves.  I don't think we
need to lose sleep over this, unless this is demonstrated to be a
problem in the real world.