#
# This file is free software, which comes along with NIT. This software is
# distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
-# without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+# without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
# PARTICULAR PURPOSE. You can modify it is you want, provided this header
# is kept unaltered, and a notification of the changes is added.
# You are allowed to redistribute it and sell it, alone or is a part of
class Range[E: Discrete]
super Collection[E]
- redef var first: E
+ redef var first
# Get the last element.
var last: E
# Get the element after the last one.
var after: E
- redef fun has(item) do return item >= first and item <= last
+ # assert [1..10].has(5)
+ # assert [1..10].has(10)
+ # assert not [1..10[.has(10)
+ redef fun has(item) do return item isa Comparable and item >= first and item <= last
+ # assert [1..1].has_only(1)
+ # assert not [1..10].has_only(1)
redef fun has_only(item) do return first == item and item == last or is_empty
+ # assert [1..10].count(1) == 1
+ # assert [1..10].count(0) == 0
redef fun count(item)
do
if has(item) then
redef fun iterator do return new IteratorRange[E](self)
+ # Gets an iterator starting at the end and going backwards
+ #
+ # var reviter = [1..4].reverse_iterator
+ # assert reviter.to_a == [4,3,2,1]
+ #
+ # reviter = [1..4[.reverse_iterator
+ # assert reviter.to_a == [3,2,1]
+ fun reverse_iterator: Iterator[E] do return new ReverseIteratorRange[E](self)
+
+ # assert [1..10].length == 10
+ # assert [1..10[.length == 9
+ # assert [1..1].length == 1
+ # assert [1..-10].length == 0
redef fun length
do
+ if is_empty then return 0
var nb = first.distance(after)
if nb > 0 then
return nb
end
end
+ # assert not [1..10[.is_empty
+ # assert not [1..1].is_empty
+ # assert [1..-10].is_empty
redef fun is_empty do return first >= after
# Create a range [`from`, `to`].
- # The syntax `[from..to[` is equivalent.
+ # The syntax `[from..to]` is equivalent.
+ #
+ # var a = [10..15]
+ # var b = new Range[Int] (10,15)
+ # assert a == b
+ # assert a.to_a == [10, 11, 12, 13, 14, 15]
init(from: E, to: E) is old_style_init do
first = from
last = to
# Create a range [`from`, `to`[.
# The syntax `[from..to[` is equivalent.
+ #
+ # var a = [10..15[
+ # var b = new Range[Int].without_last(10,15)
+ # assert a == b
+ # assert a.to_a == [10, 11, 12, 13, 14]
init without_last(from: E, to: E)
do
first = from
- last = to.predecessor(1)
- after = to
+ if from <= to then
+ last = to.predecessor(1)
+ after = to
+ else
+ last = to.successor(1)
+ after = to
+ end
+ end
+
+ # Two ranges are equals if they have the same first and last elements.
+ #
+ # var a = new Range[Int](10, 15)
+ # var b = new Range[Int].without_last(10, 15)
+ # assert a == [10..15]
+ # assert a == [10..16[
+ # assert not a == [10..15[
+ # assert b == [10..15[
+ # assert b == [10..14]
+ # assert not b == [10..15]
+ redef fun ==(o) do
+ return o isa Range[E] and self.first == o.first and self.last == o.last
+ end
+
+ # var a = new Range[Int](10, 15)
+ # assert a.hash == 455
+ # var b = new Range[Int].without_last(10, 15)
+ # assert b.hash == 432
+ redef fun hash do
+ # 11 and 23 are magic numbers empirically determined to be not so bad.
+ return first.hash * 11 + last.hash * 23
+ end
+
+ # Gets an iterator that progress with a given step.
+ #
+ # The main usage is in `for` construction.
+ #
+ # ~~~
+ # for i in [10..25].step(10) do assert i == 10 or i == 20
+ # ~~~
+ #
+ # But `step` is usable as any kind of iterator.
+ #
+ # ~~~
+ # assert [10..27].step(5).to_a == [10,15,20,25]
+ # ~~~
+ #
+ # If `step == 1`, then it is equivalent to the default `iterator`.
+ #
+ # ~~~
+ # assert [1..5].step(1).to_a == [1..5].to_a
+ # ~~~
+ #
+ # If `step` is negative, then the iterator will iterate on ranges whose `first` > `last`.
+ #
+ # ~~~
+ # assert [25..12].step(-5).to_a == [25,20,15]
+ # ~~~
+ #
+ # On such ranges, the default `iterator` will be empty
+ #
+ # ~~~
+ # assert [5..1].step(1).to_a.is_empty
+ # assert [5..1].iterator.to_a.is_empty
+ # assert [5..1].to_a.is_empty
+ # assert [5..1].is_empty
+ # ~~~
+ #
+ # Note that on non-empty range, iterating with a negative step will be empty
+ #
+ # ~~~
+ # assert [1..5].step(-1).to_a.is_empty
+ # ~~~
+ fun step(step: Int): Iterator[E]
+ do
+ var i
+ if step >= 0 then
+ i = iterator
+ else
+ i = new DowntoIteratorRange[E](self)
+ step = -step
+ end
+
+ if step == 1 then return i
+ return i.to_step(step)
end
end
+# Iterator on ranges.
private class IteratorRange[E: Discrete]
- # Iterator on ranges.
super Iterator[E]
var range: Range[E]
redef var item is noinit
redef fun is_ok do return _item < _range.after
-
+
redef fun next do _item = _item.successor(1)
-
+
+ init
+ do
+ _item = _range.first
+ end
+end
+
+# Reverse iterator on ranges.
+private class ReverseIteratorRange[E: Discrete]
+ super Iterator[E]
+ var range: Range[E]
+ redef var item is noinit
+
+ redef fun is_ok do return _item >= _range.first
+
+ redef fun next do _item = _item.predecessor(1)
+
+ init
+ do
+ _item = _range.last
+ end
+end
+
+# Iterator on ranges.
+private class DowntoIteratorRange[E: Discrete]
+ super IndexedIterator[E]
+ var range: Range[E]
+ redef var item is noinit
+ redef fun index do return _item.distance(_range.first)
+
+ redef fun is_ok do return _item >= _range.last
+
+ redef fun next do _item = _item.predecessor(1)
+
init
do
_item = _range.first
end
redef class Int
- # Returns the range from 0 to `self-1`, is used to do:
+ # Returns the range from 0 to `self-1`.
+ #
+ # assert 3.times == [0..3[
+ # assert 10.times == [0..10[
+ # assert ((-1).times).is_empty
+ #
+ # This can be usefull for loops:
#
# var s = new Array[String]
# for i in 3.times do s.add "cool"
# assert s.join(" ") == "cool cool cool"
- #
- # s.clear
- # for i in 10.times do s.add(i.to_s)
- # assert s.to_s == "0123456789"
fun times: Range[Int] do return [0 .. self[
end
nitlanguage / nit.git / blobdiff