Re: Effeciency of any predicate

Pascal Costanza <pc@xxxxxxxxx> writes:
Style comments:

- In Common Lisp, it's unusual to use the question mark to indicate
predicates. It's more usual to have predicates end in p (like numberp,
listp, etc.). And even that is not a strict rule.

A little bit of background that may help the original poster
understand this. On page 33 of CLtL2 Steele explains

Many people have suggested that brackets be used to
notate vectors, as [a b c] instead of #(a b c)
... However, to preserve the usefulness of the
user-definable macro-character feature of the function
read, it is necessary to leave some characters to the
user for this purpose.

http://www.franz.com/support/documentation/6.2/ansicl/subsecti/characte.htm

tells you that six characters are ! ? [ ] { }

The idea is that you are going to define a read macro for ?
and then you will have to escape any? as |any?| or any\? to
avoid triggering that read macro.

Alan Crowe
Edinburgh
Scotland
.

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