constant folding/smashing (constant hash tables)

[sandra@cs.utah.edu (Sandra J Loosemore)]

> From: edsel!jonl@labrea.stanford.edu (Jon L White)
> Subject: constant folding/smashing
> 
> re:     What about constant hash-tables?  No variety of QUOTE can build
>         a constant hash table because there is no notation for them.
>         (I don't count #.(make-hash-table...) because it's so gross.)
> 
> There is a proposal before X3J13 now (presented by Dave Touretzky) to
> give a printable representation to hashtables.  If a sufficiently powerful 
> version of it is adopted, then it should be possible to use QUOTE to 
> reference a constant hashtable.

There is already a way to make a constant hashtable with QUOTE.  Try:

    (defmacro make-a-constant-hash-table ()
        `(quote ,(make-hash-table ...)))

This same trick can also be used to make "constants" out of other kinds
of weird objects, like packages or streams.

-Sandra
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