compareTo method
Events are ordered first by their x-value, and then by their eventType. Insert events are sorted before Delete events, so that items whose Insert and Delete events occur at the same x-value will be correctly handled.
Implementation
int compareTo(dynamic o) {
SweepLineEvent pe = o;
if (xValue < pe.xValue) return -1;
if (xValue > pe.xValue) return 1;
if (eventType < pe.eventType) return -1;
if (eventType > pe.eventType) return 1;
return 0;
}