restructured library manual accordiung to functional group

Doc/lib/libobjs.tex

@@ -4,16 +4,21 @@
 
 Names for built-in exceptions and functions are found in a separate
 symbol table.  This table is searched last, so local and global
-user-defined names can override built-in names.  Built-in types have
-no names but are created easily by constructing an object of the
-desired type (e.g., using a literal) and applying the built-in
-function \code{type()} to it.  They are described together here for
-easy reference.%
-\footnote{Some descriptions sorely lack explanations of the exceptions
+user-defined names can override built-in names.  Built-in types are
+described together here for easy reference.  %
+\footnote{Most descriptions sorely lack explanations of the exceptions
 	that may be raised --- this will be fixed in a future version of
-	this document.}
+	this manual.}
 \indexii{built-in}{types}
 \indexii{built-in}{exceptions}
 \indexii{built-in}{functions}
 \index{symbol table}
 \bifuncindex{type}
+
+The tables in this chapter document the priorities of operators by
+listing them in order of ascending priority (within a table) and
+grouping operators that have the same priority in the same box.
+Binary operators of the same priority group from left to right.
+(Unary operators group from right to left, but there you have no real
+choice.)  See Chapter 5 of the Python Reference Manual for the
+complete picture on operator priorities.