The nonexistent operator (along = v. == lines)

[Jim Giles]

> [...]
>   It can't be done.  The truth or falseness of a ^ expression
> cannot be determined without evaluating all the operands. [...]

What you are saying is obvious.  However, the original request
was for a _logical_ XOR instead of a _bit-wise_ XOR.  The fact
that you can't short-circuit XOR is irrelevant to that request.

This is one of the problems with confounding two distinct concepts
into one language feature - people soon begin to believe the two
concepts are inseparable.  In this case, short-circuiting and 
logical con/disjunction are distinct concepts that just happen
to be combined into single operators.

J. Giles