Pair<A, B> class
class Pair<A, B> {
final A fst;
final B snd;
Pair(this.fst, this.snd);
bool operator ==(Pair<A, B> other) =>
(other is Pair<A, B>)
&& fst == other.fst
&& snd == other.snd;
int get hashCode => fst.hashCode + 31 * snd.hashCode;
String toString() => "Pair($fst, $snd)";
}
Constructors
Properties
final int hashCode #
Get a hash code for this object.
All objects have hash codes. Hash codes are guaranteed to be the
same for objects that are equal when compared using the equality
operator ==. Other than that there are no guarantees about
the hash codes. They will not be consistent between runs and
there are no distribution guarantees.
If a subclass overrides hashCode it should override the equality operator as well to maintain consistency.
int get hashCode => fst.hashCode + 31 * snd.hashCode;
Operators
bool operator ==(Pair<A, B> other) #
The equality operator.
The default behavior for all Objects is to return true if and
only if this and
other are the same object.
Override this method to specify a different equality relation on a class. The overriding method must still be an equivalence relation. That is, it must be:
-
Total: It must return a boolean for all arguments. It should never throw or return
null. -
Reflexive: For all objects
o,o == omust be true. -
Symmetric: For all objects
o1ando2,o1 == o2ando2 == o1must either both be true, or both be false. -
Transitive: For all objects
o1,o2, ando3, ifo1 == o2ando2 == o3are true, theno1 == o3must be true.
The method should also be consistent over time, so equality of two objects should not change over time, or at least only change if one of the objects was modified.
If a subclass overrides the equality operator it should override the hashCode method as well to maintain consistency.
bool operator ==(Pair<A, B> other) => (other is Pair<A, B>) && fst == other.fst && snd == other.snd;