Iterate cyclically over lst.
lst is a list of arbitrary objects to iterate through.
step jump size and direction across list.
start : the index of lst where the function begins iterating.
infinitely.
The function returns a generator.
Examples:
abjad> l = [1, 2, 3, 4, 5, 6, 7]
abjad> g = listtools.phasor(l)
abjad> for i in range(20):
... print g.next( ),
...
1 2 3 4 5 6 7 1 2 3 4 5 6 7 1 2 3 4 5 6
abjad> listtools.phasor(l, 2, length = 20)
<generator object at 0x8264acc>
abjad> list(_)
[1, 3, 5, 7, 2, 4, 6, 1, 3, 5, 7, 2, 4, 6, 1, 3, 5, 7, 2, 4]
abjad> listtools.phasor(l, 2, 3, length = 20)
<generator object at 0x8264acc>
abjad> list(_)
[4, 6, 1, 3, 5, 7, 2, 4, 6, 1, 3, 5, 7, 2, 4, 6, 1, 3, 5, 7]
abjad> listtools.phasor(l, -2, 5, length = 20)
<generator object at 0x8264acc>
abjad> list(_)
[6, 4, 2, 7, 5, 3, 1, 6, 4, 2, 7, 5, 3, 1, 6, 4, 2, 7, 5, 3]