Per Bothner <xxxxxx@bothner.com> writes:

> Thomas Bushnell BSG wrote:
>> Alan Watson <xxxxxx@astrosmo.unam.mx> writes:
>>
>>> NaNs are atoms -- they have no context or stucture, just a single
>>> value. With the understandable exception of the eof object (and as
>>> has been noted, this is exception is not universal), Lisps and
>>> Schemes tranditionally provide read syntax for atoms. So, tradition
>>> suggests that we should have a read syntax for NaNs.
>> Hogwash.  Procedures are atoms.
>
> Wrong.  Closures can be modified.

Where is the Scheme function which modifies closures?

I was always taught that an atom is anything which is not a cons.  :)
At least, the Little Lisper says so.

But that aside, NaNs could also have structure, as has been pointed
out; it could be useful for them to come with a tag identifying their
origin.

Thomas