blob: dda3dd57c1cf5cff74adc6967d74b088e7a00e8e (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
|
def peek_and_iter(items):
if not items:
return None, None
items = iter(items)
try:
peeked = next(items)
except StopIteration:
return None, None
def chain():
yield peeked
yield from items
return chain(), peeked
def iter_many(items, onempty=None):
if not items:
if onempty is None:
return
if not callable(onempty):
raise onEmpty
items = onempty(items)
yield from iter_many(items, onempty=None)
return
items = iter(items)
try:
first = next(items)
except StopIteration:
if onempty is None:
return
if not callable(onempty):
raise onEmpty
items = onempty(items)
yield from iter_many(items, onempty=None)
else:
try:
second = next(items)
except StopIteration:
yield first, False
return
else:
yield first, True
yield second, True
for item in items:
yield item, True
|
