More tests.
diff --git a/Lib/test/test_generators.py b/Lib/test/test_generators.py
index 947697a..f3cba56 100644
--- a/Lib/test/test_generators.py
+++ b/Lib/test/test_generators.py
@@ -5,6 +5,10 @@
... yield 1
... yield 2
+ >>> for i in f():
+ ... print i
+ 1
+ 2
>>> g = f()
>>> g.next()
1
@@ -203,7 +207,6 @@
[1, 2, 4, 5, 8, 9, 10, 11]
>>>
-
Guido's binary tree example.
>>> # A binary tree class.
@@ -301,6 +304,18 @@
... yield 3
>>> list(g())
[1, 2, 3]
+
+A generator can't be resumed while it's already running.
+
+>>> def g():
+... i = me.next()
+... yield i
+>>> me = g()
+>>> me.next()
+Traceback (most recent call last):
+ ...
+ File "<string>", line 2, in g
+ValueError: generator already executing
"""
# Fun tests (for sufficiently warped notions of "fun").
@@ -338,6 +353,58 @@
>>> primes = sieve(intsfrom(2))
>>> firstn(primes, 20)
[2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71]
+
+Another famous problem: generate all integers of the form
+ 2**i * 3**j * 5**k
+in increasing order, where i,j,k >= 0. Trickier than it may look at first!
+Try writing it without generators, and correctly, and without generating
+3 internal results for each result output.
+
+>>> def times(n, g):
+... for i in g:
+... yield n * i
+>>> firstn(times(10, intsfrom(1)), 10)
+[10, 20, 30, 40, 50, 60, 70, 80, 90, 100]
+
+>>> def merge(g, h):
+... ng = g.next()
+... nh = h.next()
+... while 1:
+... if ng < nh:
+... yield ng
+... ng = g.next()
+... elif ng > nh:
+... yield nh
+... nh = h.next()
+... else:
+... yield ng
+... ng = g.next()
+... nh = h.next()
+
+This works, but is doing a whale of a lot or redundant work -- it's not
+clear how to get the internal uses of m235 to share a single generator.
+Note that me_times2 (etc) each need to see every element in the result
+sequence. So this is an example where lazy lists are more natural (you
+can look at the head of a lazy list any number of times).
+
+>>> def m235():
+... yield 1
+... me_times2 = times(2, m235())
+... me_times3 = times(3, m235())
+... me_times5 = times(5, m235())
+... for i in merge(merge(me_times2,
+... me_times3),
+... me_times5):
+... yield i
+
+>>> result = m235()
+>>> for i in range(5):
+... print firstn(result, 15)
+[1, 2, 3, 4, 5, 6, 8, 9, 10, 12, 15, 16, 18, 20, 24]
+[25, 27, 30, 32, 36, 40, 45, 48, 50, 54, 60, 64, 72, 75, 80]
+[81, 90, 96, 100, 108, 120, 125, 128, 135, 144, 150, 160, 162, 180, 192]
+[200, 216, 225, 240, 243, 250, 256, 270, 288, 300, 320, 324, 360, 375, 384]
+[400, 405, 432, 450, 480, 486, 500, 512, 540, 576, 600, 625, 640, 648, 675]
"""
__test__ = {"tut": tutorial_tests,