updated from Atlas

16-coroutine/yield_from_expansion_simplified.py

@@ -0,0 +1,32 @@
+# Code below is a very simplified expansion of the statement:
+#
+# RESULT = yield from EXPR
+#
+# This code assumes that the subgenerator will run to completion,
+# without the client ever calling ``.throw()`` or ``.close()``.
+# Also, this code makes no distinction between the client
+# calling ``next(subgen)`` or ``subgen.send(...)``
+#
+# The full expansion is in:
+# PEP 380 -- Syntax for Delegating to a Subgenerator
+#
+# https://www.python.org/dev/peps/pep-0380/#formal-semantics
+
+
+# BEGIN YIELD_FROM_EXPANSION_SIMPLIFIED
+_i = iter(EXPR)  # <1>
+try:
+    _y = next(_i)  # <2>
+except StopIteration as _e:
+    _r = _e.value  # <3>
+else:
+    while 1:  # <4>
+        _s = yield _y  # <5>
+        try:
+            _y = _i.send(_s)  # <6>
+        except StopIteration as _e:  # <7>
+            _r = _e.value
+            break
+
+RESULT = _r  # <8>
+# END YIELD_FROM_EXPANSION_SIMPLIFIED