Merge pull request #383 from pfalcon/yield-from

Implement "yield from"

1 files changed, 87 insertions, 0 deletions

diff --git a/tests/basics/gen-yield-from-close.py b/tests/basics/gen-yield-from-close.py
new file mode 100644
index 0000000000..7982d5c990
--- /dev/null
+++ b/tests/basics/gen-yield-from-close.py
@@ -0,0 +1,87 @@
+def gen():
+    yield 1
+    yield 2
+    yield 3
+    yield 4
+
+def gen2():
+    yield -1
+    print((yield from gen()))
+    yield 10
+    yield 11
+
+g = gen2()
+print(next(g))
+print(next(g))
+g.close()
+try:
+    print(next(g))
+except StopIteration:
+    print("StopIteration")
+
+
+# Now variation of same test, but with leaf generator
+# swallowing GeneratorExit exception - its upstream gen
+# generator should still receive one.
+def gen3():
+    yield 1
+    try:
+        yield 2
+    except GeneratorExit:
+        print("leaf caught GeneratorExit and swallowed it")
+        return
+    yield 3
+    yield 4
+
+def gen4():
+    yield -1
+    try:
+        print((yield from gen3()))
+    except GeneratorExit:
+        print("delegating caught GeneratorExit")
+        raise
+    yield 10
+    yield 11
+
+g = gen4()
+print(next(g))
+print(next(g))
+print(next(g))
+g.close()
+try:
+    print(next(g))
+except StopIteration:
+    print("StopIteration")
+
+
+# Yet another variation - leaf generator gets GeneratorExit,
+# but raises StopIteration instead. This still should close chain properly.
+def gen5():
+    yield 1
+    try:
+        yield 2
+    except GeneratorExit:
+        print("leaf caught GeneratorExit and raised StopIteration instead")
+        raise StopIteration(123)
+    yield 3
+    yield 4
+
+def gen6():
+    yield -1
+    try:
+        print((yield from gen5()))
+    except GeneratorExit:
+        print("delegating caught GeneratorExit")
+        raise
+    yield 10
+    yield 11
+
+g = gen6()
+print(next(g))
+print(next(g))
+print(next(g))
+g.close()
+try:
+    print(next(g))
+except StopIteration:
+    print("StopIteration")