core_range library Core
Utilities for representing and manipulating a range of values in a domain.
A Range is a convex (contiguous) portion of a domain. It may be finitely constrained, i.e. 0 <= x < 5,
or extend to infinity, i.e. x > 3.
It is recommended to use this library only if you require non-trivial range manipulation. A record, i.e. (min, max)
is otherwise preferred.
Types of ranges
Each end of a range may be either bound or unbounded. If bounded, a minimum or maximum value is associated with a
range's end. Furthermore, a bounded range's end is either closed (includes the value), or open (excludes the value).
For example, a closed-open range can be denoted as 0 <= x < 5.
The following table describes the types of ranges supported by this library.
| Notation | Range | Type/Constructor |
|---|---|---|
(-∞..+∞) |
{ x | x } |
Unbound |
(a..+∞) |
{ x | a < x } |
Min |
[a..+∞) |
{ x | a <= x } |
Min |
(a..b) |
{ x | a < x < b } |
Interval.open |
(a..b] |
{ x | a < x <= b } |
Interval.openClosed |
[a..b] |
{ x | a <= x <= b } |
Interval.closed |
[a..b) |
{ x | a < x <= b } |
Interval.closedOpen |
(-∞..b) |
{ x | x < b } |
Max |
(-∞..b] |
{ x | x <= b } |
Max |
In addition, the following ranges are valid:
- singleton ranges -
[a..a] - empty ranges -
[a..a)and(a..a]
Ranges with open bounds and, equal minimum and maximum values, i.e. (a..b) are not valid.
Example
final hoursInDay = Interval.closedOpen(0, 24);
print(hoursInDay.contains(0); // true
print(hoursInDay.contains(12); // true
print(hoursInDay.contains(24); // false
Classes
-
Interval<
T extends Comparable< Object?> > -
An Interval represents a convex (contiguous) portion of a domain bounded on both ends, i.e.
{ x | min < x < max }. -
IterableRange<
T extends Comparable< Object?> > - A Range that is also iterable.
-
Max<
T extends Comparable< Object?> > -
A Max represents a convex (contiguous) portion of a domain bounded on the upper end, i.e.
{ x | x < value }. -
Min<
T extends Comparable< Object?> > -
A Min represents a convex (contiguous) portion of a domain bounded on the lower end, i.e.
{ x | value < x }. -
Range<
T extends Comparable< Object?> > - A Range represents a convex (contiguous) portion of a domain.
-
Unbound<
T extends Comparable< Object?> > -
An Unbound interval represents a convex (contiguous) portion of a domain unbounded on both ends, i.e.
{ x | x }.