comma operator (really about xor)

[Frank Adams]

In article <131 at puivax.UUCP> ian at puivax.UUCP (Ian Wilson) writes:
>The transformation works whatever the values of A & B happen to
>be - exclusive or being the only information-preserving logical
>operation.

A quibble -- exclusive or is not the only information-preserving (binary)
logical operation.  Equivalence also has this property.  One can also use
equivalence instead of exclusive or in the exchange algorithm.

Of course, equivalence isn't really very different from exclusive or -- just
interchange the role of the zeros and ones, and you get one from the other.
-- 

Frank Adams                           ihnp4!philabs!pwa-b!mmintl!franka
Ashton-Tate          52 Oakland Ave North         E. Hartford, CT 06108