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dsugden/MutableBad.scala

Last active August 29, 2015 14:02
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Example of dangers of mutation
Raw
MutableBad.scala
object MutableBad{
class MDate(dayIn:Int){ var day = dayIn }
type Task = Int
def scheduleTask(task:Task,date:MDate) = ???
var d = new MDate(22)
scheduleTask(1, d) // some other code block has a reference to d, changing d would be bad
d.day = 33 // WAT??, I should have made a defensive copy of d
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