note 118443 deleted from migration70.new-features by salathe

Note Submitter: Anonymous ---- The key difference between the spaceship operator and the sign function is that the sign function returns the sign of a single value or expression, while the spaceship <=> returns, in a single operation, the results of the <, <=, ==, !=, >= and > operators aplied to the same pair of values or expressions. It also differ from sgn(a - b) in that it doesn't require the subtraction to be valid, in range or well defined. For example (largestnum <=> -largestnum) is valid while sgn(largestnum - (-largestnum)) involves a numeric overflow in the subtraction.