but aren't those operators supposed to associate right to left?
Unary plus/minus associativity is right-to-left.
Addition/subtraction is left-to-right.
Robert Wishlaw
Ah! Thanks.
To ease my embarrassment, here's a genuine error, but it's only in the help files, under the entry for atan2:
Purpose:
Calculates arctangent of y / x.
Returns:
Arctangent of x / y.
...a bug in v4.50, but corrected for v5.00.