clamp method
Returns this num clamped to be in the range lowerLimit-upperLimit.
The comparison is done using compareTo and therefore takes -0.0 into
account. This also implies that double.nan is treated as the maximal
double value.
The arguments lowerLimit and upperLimit must form a valid range where
lowerLimit.compareTo(upperLimit) <= 0.
Implementation
num clamp(num lowerLimit, num upperLimit);