operator - method
subtraction operator for RollResult.
Results create new list lhs.results + (-1)*(other.results).
Implementation
RollResult operator -(RollResult other) => RollResult.fromRollResult(
other,
expression: '($expression - ${other.expression})',
opType: OpType.subtract,
results: results + other.results.map((v) => v * -1).toList(),
nsides: max(nsides, other.nsides),
left: this,
right: other,
);