Revise the markup related to the grammar productions to increase the

level of predictability.  This is not really "good" markup, but is arguably
better than we had before.
This closes SF bug #523117.

Doc/ref/ref6.tex

@@ -6,22 +6,21 @@ Several simple statements may occur on a single line separated
 by semicolons.  The syntax for simple statements is:
 
 \begin{productionlist}
-  \production{simple_stmt}
-             {\token{expression_stmt}
-              | \token{assert_stmt}
-              | \token{assignment_stmt}
-              | \token{augmented_assignment_stmt}
-              | \token{pass_stmt}
-              | \token{del_stmt}
-              | \token{print_stmt}
-              | \token{return_stmt}
-              | \token{yield_stmt}
-              | \token{raise_stmt}
-              | \token{break_stmt}
-              | \token{continue_stmt}
-              | \token{import_stmt}
-              | \token{global_stmt}
-              | \token{exec_stmt}}
+  \production{simple_stmt}{\token{expression_stmt}}
+  \productioncont{| \token{assert_stmt}}
+  \productioncont{| \token{assignment_stmt}}
+  \productioncont{| \token{augmented_assignment_stmt}}
+  \productioncont{| \token{pass_stmt}}
+  \productioncont{| \token{del_stmt}}
+  \productioncont{| \token{print_stmt}}
+  \productioncont{| \token{return_stmt}}
+  \productioncont{| \token{yield_stmt}}
+  \productioncont{| \token{raise_stmt}}
+  \productioncont{| \token{break_stmt}}
+  \productioncont{| \token{continue_stmt}}
+  \productioncont{| \token{import_stmt}}
+  \productioncont{| \token{global_stmt}}
+  \productioncont{| \token{exec_stmt}}
 \end{productionlist}
 
 
@@ -112,12 +111,12 @@ objects:
   \production{target_list}
              {\token{target} ("," \token{target})* [","]}
   \production{target}
-             {\token{identifier}
-              | "(" \token{target_list} ")"
-              | "[" \token{target_list} "]"
-              | \token{attributeref}
-              | \token{subscription}
-              | \token{slicing}}
+             {\token{identifier}}
+  \productioncont{| "(" \token{target_list} ")"}
+  \productioncont{| "[" \token{target_list} "]"}
+  \productioncont{| \token{attributeref}}
+  \productioncont{| \token{subscription}}
+  \productioncont{| \token{slicing}}
 \end{productionlist}
 
 (See section~\ref{primaries} for the syntax definitions for the last
@@ -264,7 +263,7 @@ print x
 \end{verbatim}
 
 
-\subsection{Augmented Assignment statements \label{augassign}}
+\subsection{Augmented assignment statements \label{augassign}}
 
 Augmented assignment is the combination, in a single statement, of a binary
 operation and an assignment statement:
@@ -275,15 +274,8 @@ operation and an assignment statement:
   \production{augmented_assignment_stmt}
              {\token{target} \token{augop} \token{expression_list}}
   \production{augop}
-             {"+=" | "-=" | "*=" | "/=" | "\%=" | "**="
-              | ">>=" | "<<=" | "\&=" | "\textasciicircum=" | "|="}
-  \production{target}
-             {\token{identifier}
-              | "(" \token{target_list} ")"
-              | "[" \token{target_list} "]"
-              | \token{attributeref}
-              | \token{subscription}
-              | \token{slicing}}
+             {"+=" | "-=" | "*=" | "/=" | "\%=" | "**="}
+  \productioncont{| ">>=" | "<<=" | "\&=" | "\textasciicircum=" | "|="}
 \end{productionlist}
 
 (See section~\ref{primaries} for the syntax definitions for the last
@@ -364,9 +356,9 @@ right type (but even this is determined by the sliced object).
 
 \begin{productionlist}
   \production{print_stmt}
-             {"print" ( \optional{\token{expression} ("," \token{expression})* \optional{","}}
-                      | ">\code{>}" \token{expression}
-                        \optional{("," \token{expression})+ \optional{","}})}
+             {"print" ( \optional{\token{expression} ("," \token{expression})* \optional{","}}}
+  \productioncont{| ">\code{>}" \token{expression}
+                  \optional{("," \token{expression})+ \optional{","}} )}
 \end{productionlist}
 
 \keyword{print} evaluates each expression in turn and writes the
@@ -600,11 +592,11 @@ It continues with the next cycle of the nearest enclosing loop.
 \begin{productionlist}
   \production{import_stmt}
              {"import" \token{module} ["as" \token{name}]
-                ( "," \token{module} ["as" \token{name}] )*
-              | "from" \token{module} "import" \token{identifier}
-                ["as" \token{name}]
-                ( "," \token{identifier} ["as" \token{name}] )*
-              | "from" \token{module} "import" "*"}
+                ( "," \token{module} ["as" \token{name}] )*}
+  \productioncont{| "from" \token{module} "import" \token{identifier}
+                    ["as" \token{name}]}
+  \productioncont{  ( "," \token{identifier} ["as" \token{name}] )*}
+  \productioncont{| "from" \token{module} "import" "*"}
   \production{module}
              {(\token{identifier} ".")* \token{identifier}}
 \end{productionlist}