Hi Christophe,

> <pelletier.mic...@gmail.com> wrote:
> >
> > If NIL doesn't exist at all, then why do you need to expose it?  If
> > you language exposes lists or strings then empty ones carry the same
> > meaning.
> 
> I don't want to expose it.
> Sorry, maybe I wasn't clear enough.
> In particular, I'd like my users to type in a REPL "",
> and see the result "", not NIL.

Well, as Michel said, then it is easy, isn't it? You just change the
print routine to output '""' instead of 'NIL'.


Concerning your original question:

NIL representing the empty string seems so natural to me, that I never
thought much about it, and have difficulties to imagine a life without
it ;)

A few points about the background come to mind, though:
   * It wouldn't work smoothly in conditionals any longer ('cond', 'if',
     'and', 'or' etc.)
   * It would take up space in property-lists and in the database
   * If the empty string were a transient symbol, it would no longer be
     uniqe, and '==', 'memq', 'asoq', 'throw' etc. cannot be used on it

What type of object would '""' be? Not an internal symbol, as the double
quotes point to a transient symbol. Transient symbols without name are
anonymous symbols, however, which are created with 'new' and 'box', and
which print as something like '$177702023320760'. If you print them all
as '""', anynymous symbols cannot be distinguished any longer, e.g.
during debugging, and some tools like 'edit' would not be able to handle
them.

♪♫ Alex
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