require list comprehensions to start with a for clause
diff --git a/Doc/ref/ref5.tex b/Doc/ref/ref5.tex
index 1abc6cb..f6d3b9c 100644
--- a/Doc/ref/ref5.tex
+++ b/Doc/ref/ref5.tex
@@ -153,7 +153,7 @@
\begin{verbatim}
list_display: "[" [listmaker] "]"
-listmaker: expression ( list_iter | ( "," expression)* [","] )
+listmaker: expression ( list_for | ( "," expression)* [","] )
list_iter: list_for | list_if
list_for: "for" expression_list "in" testlist [list_iter]
list_if: "if" test [list_iter]
@@ -164,7 +164,8 @@
When a comma-separated list of expressions is supplied, its elements are
evaluated from left to right and placed into the list object in that
order. When a list comprehension is supplied, it consists of a
-single expression followed by one or more "for" or "if" clauses. In this
+single expression followed by at least one "for" clause and zero or more
+"for" or "if" clauses. In this
case, the elements of the new list are those that would be produced
by considering each of the "for" or "if" clauses a block, nesting from
left to right, and evaluating the expression to produce a list element