Add comments and move a few declaration blocks to help readability.

 No functional changes this time!

src/backend/parser/scan.l

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/parser/scan.l,v 1.30 1997/11/20 23:22:25 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/parser/scan.l,v 1.31 1997/11/30 23:05:36 thomas Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -60,7 +60,7 @@ int llen;
 char literal[MAX_PARSE_BUFFER];
 
 %}
-	/* OK, here is a short description of lex/flex rules behavior.
+/* OK, here is a short description of lex/flex rules behavior.
  * The longest pattern which matches an input string is always chosen.
  * For equal-length patterns, the first occurring in the rules list is chosen.
  * INITIAL is the starting condition, to which all non-conditional rules apply.
@@ -71,11 +71,11 @@ char literal[MAX_PARSE_BUFFER];
  *  and to eliminate parsing troubles for numeric strings.
  * Exclusive states:
  *  <xb> binary numeric string - thomas 1997-11-16
-	 *  <xh> hexadecimal numeric string - thomas 1997-11-16
  *  <xc> extended C-style comments - tgl 1997-07-12
-	 *  <xq> quoted strings - tgl 1997-07-30
-	 *  <xm> numeric strings with embedded minus sign - tgl 1997-09-05
  *  <xd> delimited identifiers (double-quoted identifiers) - tgl 1997-10-27
+ *  <xh> hexadecimal numeric string - thomas 1997-11-16
+ *  <xm> numeric strings with embedded minus sign - tgl 1997-09-05
+ *  <xq> quoted strings - tgl 1997-07-30
  *
  * The "extended comment" syntax closely resembles allowable operator syntax.
  * So, when in condition <xc>, only strings which would terminate the
@@ -88,33 +88,47 @@ char literal[MAX_PARSE_BUFFER];
 %x xc
 %x xd
 %x xh
-%x xq
 %x xm
+%x xq
 
-quote			'
-xqstart			{quote}
-xqstop			{quote}
-xqdouble		{quote}{quote}
-xqinside		[^\\']*
-xqembedded		"\\'"
-xqliteral		[\\](.|\n)
-xqcat			{quote}{space}*\n{space}*{quote}
-
+/* Binary number
+ */
 xbstart			[bB]{quote}
 xbstop			{quote}
 xbinside		[^']*
 xbcat			{quote}{space}*\n{space}*{quote}
 
+/* Hexadecimal number
+ */
 xhstart			[xX]{quote}
 xhstop			{quote}
 xhinside		[^']*
 xhcat			{quote}{space}*\n{space}*{quote}
 
+/* Extended quote
+ * xqdouble implements SQL92 embedded quote
+ * xqcat allows strings to cross input lines
+ */
+quote			'
+xqstart			{quote}
+xqstop			{quote}
+xqdouble		{quote}{quote}
+xqinside		[^\\']*
+xqembedded		"\\'"
+xqliteral		[\\](.|\n)
+xqcat			{quote}{space}*\n{space}*{quote}
+
+/* Delimited quote
+ * Allows embedded spaces and other special characters into identifiers.
+ */
 dquote			\"
 xdstart			{dquote}
 xdstop			{dquote}
 xdinside		[^"]*
 
+/* Comments
+ * Ignored by the scanner and parser.
+ */
 xcline			[\/][\*].*[\*][\/]{space}*\n*
 xcstart			[\/][\*]{op_and_self}*
 xcstop			{op_and_self}*[\*][\/]({space}*|\n)