clarify discussion of iteration in the section on the "for" statement
(SF bug #829073)
diff --git a/Doc/ref/ref7.tex b/Doc/ref/ref7.tex
index 92ee655..5e50a74 100644
--- a/Doc/ref/ref7.tex
+++ b/Doc/ref/ref7.tex
@@ -134,8 +134,10 @@
\productioncont{["else" ":" \token{suite}]}
\end{productionlist}
-The expression list is evaluated once; it should yield a sequence. The
-suite is then executed once for each item in the sequence, in the
+The expression list is evaluated once; it should yield an iterable
+object. An iterator is created for the result of the
+{}\code{expression_list}. The suite is then executed once for each
+item provided by the iterator, in the
order of ascending indices. Each item in turn is assigned to the
target list using the standard rules for assignments, and then the
suite is executed. When the items are exhausted (which is immediately