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Re: dynamic vs. static typing

Paul F. Dietz wrote:
> Scott McKay wrote:
>> No, no, no.  In Lisp, all parameters are passed by "object
>> reference" (*).  Some of these objects are mutable, so you
>> can change "parts" of them.  Integers happen to be immutable,
>> so there's no part of it you can change.
> However, in Common Lisp, a conforming implementation is allowed
> to copy numbers or characters at any time, so no conforming program
> may depend on their object identity being preserved.  The
> form (EQ X X) needn't evaluate to a true value if X has
> a number or character value.

...but if (EQ X Y) evaluates to true then you can be sure that it is the 
same value even in the case of numbers and characters. Sometimes, this 
is all you need.


Pascal Costanza               University of Bonn
mailto:costanza@web.de        Institute of Computer Science III
http://www.pascalcostanza.de  Römerstr. 164, D-53117 Bonn (Germany)