First cut at full support for OUTER JOINs. There are still a few loose

ends to clean up (see my message of same date to pghackers), but mostly
it works.  INITDB REQUIRED!

1 files changed, 60 insertions, 6 deletions

diff --git a/src/backend/parser/parser.c b/src/backend/parser/parser.c
index a7652407b73..4a6c825498a 100644
--- a/src/backend/parser/parser.c
+++ b/src/backend/parser/parser.c
@@ -1,32 +1,40 @@
 /*-------------------------------------------------------------------------
  *
  * parser.c
+ *		Main entry point/driver for PostgreSQL parser
+ *
  *
  * Portions Copyright (c) 1996-2000, PostgreSQL, Inc
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/parser/parser.c,v 1.45 2000/04/12 17:15:27 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/parser/parser.c,v 1.46 2000/09/12 21:07:02 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
 
 #include "postgres.h"
+
+#include "nodes/parsenodes.h"
+#include "nodes/pg_list.h"
 #include "parser/analyze.h"
 #include "parser/gramparse.h"
+#include "parser/parse.h"
 #include "parser/parser.h"
 #include "parser/parse_expr.h"
 
+
 #if defined(FLEX_SCANNER)
 extern void DeleteBuffer(void);
-
 #endif	 /* FLEX_SCANNER */
 
 char	   *parseString;		/* the char* which holds the string to be
 								 * parsed */
 List	   *parsetree;			/* result of parsing is left here */
 
+static int	lookahead_token;	/* one-token lookahead */
+static bool have_lookahead;		/* lookahead_token set? */
+
 #ifdef SETS_FIXED
 static void fixupsets();
 static void define_sets();
@@ -42,11 +50,11 @@ parser(char *str, Oid *typev, int nargs)
 	List	   *queryList;
 	int			yyresult;
 
-	init_io();
-
-	parseString = pstrdup(str);
+	parseString = str;
 	parsetree = NIL;			/* in case parser forgets to set it */
+	have_lookahead = false;
 
+	scanner_init();
 	parser_init(typev, nargs);
 	parse_expr_init();
 
@@ -83,6 +91,52 @@ parser(char *str, Oid *typev, int nargs)
 	return queryList;
 }
 
+
+/*
+ * Intermediate filter between parser and base lexer (base_yylex in scan.l).
+ *
+ * The filter is needed because in some cases SQL92 requires more than one
+ * token lookahead.  We reduce these cases to one-token lookahead by combining
+ * tokens here, in order to keep the grammar LR(1).
+ *
+ * Using a filter is simpler than trying to recognize multiword tokens 
+ * directly in scan.l, because we'd have to allow for comments between the
+ * words ...
+ */
+int
+yylex(void)
+{
+	int			cur_token;
+
+	/* Get next token --- we might already have it */
+	if (have_lookahead)
+	{
+		cur_token = lookahead_token;
+		have_lookahead = false;
+	}
+	else
+		cur_token = base_yylex();
+
+	/* Do we need to look ahead for a possible multiword token? */
+	switch (cur_token)
+	{
+		case UNION:
+			/* UNION JOIN must be reduced to a single UNIONJOIN token */
+			lookahead_token = base_yylex();
+			if (lookahead_token == JOIN)
+				cur_token = UNIONJOIN;
+			else
+				have_lookahead = true;
+			break;
+
+		default:
+			break;
+	}
+
+	return cur_token;
+}
+
+
 #ifdef SETS_FIXED
 static void
 fixupsets(Query *parse)