なんとはなしに。
Date today isLeapYear " => false "
2000 asYear isLeapYear " => true "
2100 asYear isLeapYear " => false "
DateAndTime なんてのができてたんですね(3.7-)。っていうか、Magnitude のサブクラス群にいくつかの新顔wが。構成も変わっているし。
(3.6-5424) ProtoObject Object Magnitude Character Date Month Week LookupKey Association WeakKeyAssociation ReadOnlyVariableBinding WeakValueAssociation MessageTally Number Float Fraction Integer LargePositiveInteger LargeNegativeInteger SmallInteger Time TimeStamp
(3.8-6665) ProtoObject Object Magnitude Character DateAndTime TimeStamp Duration LookupKey Association WeakKeyAssociation ReadOnlyVariableBinding WeakValueAssociation MessageTally Number Float Fraction Integer LargePositiveInteger LargeNegativeInteger SmallInteger ScaledDecimal Time Timespan Date RuleDate RuleIndexDate RuleSelectionCodeDate Month Schedule Week Year VersionNumber
ScaledDecimal は固定小数点小数。Java の BigDecimal 相当? ブラウザで閲覧できるクラスコメントによると、
ScaledDecimal provides a numeric representation of fixed point decimal numbers able to accurately represent decimal fractions. It supports unbounded precision, with no limit to the number of digits before and after the decimal point.
とか。
1.1 - 1 - 0.1 " => 8.32667268468867e-17 "
1.1s1 - 1 - 0.1s1 " => 0.0s1 "
なるほど。