Sha256: d7ab5e6a457adc4c82740c107d5b3835e504effad60ad593d835aeb24a0adeec
Contents?: true
Size: 1.13 KB
Versions: 17
Compression:
Stored size: 1.13 KB
Contents
# イテレータ
class Iterator
# 列挙します
def each
begin
while next?
yield self.next
end
ensure
self.close
end
end
# 次があるか評価する
def next?
end
# 次の要素を取得
def next
end
# イテレータを破棄
def close
end
end
# 空のイテレータ
class EmptyIterator < Iterator
def next?; false; end
def next; nil; end
end
# フィルタ
class Filter < Iterator
def initialize( it, &block )
super()
@it = it
@test = block
inner_next
end
def next?
@has_next
end
def next
raise "illegal state." unless next?
begin
return @next_element
ensure
inner_next
end
end
def close
@it.close if @it
end
private
def inner_next
while @it.next?
item = @it.next
matches = @test.call( item )
if matches == :break
break
elsif matches == :true || matches == true
@has_next = true
@next_element = item
return
end
end
@has_next = false
@next_element = nil
end
end
Version data entries
17 entries across 17 versions & 2 rubygems