The expression
     -0.0 sign
returns 0.  This is according to the ANSI Smalltalk standard, 5.6.2.33, "Answer 1 if the receiver is positive, 0 if the receiver equals 0, and -1 if it is negative".   Pharo, and some interpretations of IEEE 754, disagree and expect this expression to return -1.
Last updated: 4/3/17