Fix some operator-precedence problems. New constructs IS DISTINCT FRM

and IS [NOT] OF were not being parsed consistently with other IS forms.
Also, make the world a little safer for functions named LEFT, RIGHT, etc.

diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 674a6d0d920007b32a25435b097ce2d3f8abaf59..d038cdd46e7b7486f8fa460b2f3c37896e5eeffd 100644 (file)
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -11,7 +11,7 @@
  *
  *
  * IDENTIFICATION
- *       $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 2.365 2002/09/02 02:13:01 tgl Exp $
+ *       $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 2.366 2002/09/05 22:52:48 tgl Exp $
  *
  * HISTORY
  *       AUTHOR                        DATE                    MAJOR EVENT
@@ -416,7 +416,6 @@ static void doNegateFloat(Value *v);
 /* precedence: lowest to highest */
 %left          UNION EXCEPT
 %left          INTERSECT
-%left          JOIN UNIONJOIN CROSS LEFT FULL RIGHT INNER_P NATURAL
 %left          OR
 %left          AND
 %right         NOT
@@ -425,7 +424,7 @@ static void doNegateFloat(Value *v);
 %nonassoc      LIKE ILIKE SIMILAR
 %nonassoc      ESCAPE
 %nonassoc      OVERLAPS
-%nonassoc      BETWEEN DISTINCT
+%nonassoc      BETWEEN
 %nonassoc      IN_P
 %left          POSTFIXOP               /* dummy for postfix Op rules */
 %left          Op OPERATOR             /* multi-character ops and user-defined operators */
@@ -443,6 +442,14 @@ static void doNegateFloat(Value *v);
 %left          COLLATE
 %left          TYPECAST
 %left          '.'
+/*
+ * These might seem to be low-precedence, but actually they are not part
+ * of the arithmetic hierarchy at all in their use as JOIN operators.
+ * We make them high-precedence to support their use as function names.
+ * They wouldn't be given a precedence at all, were it not that we need
+ * left-associativity among the JOIN rules themselves.
+ */
+%left          JOIN UNIONJOIN CROSS LEFT FULL RIGHT INNER_P NATURAL
 %%
 
 /*
@@ -5419,6 +5426,7 @@ r_expr:  row IN_P select_with_parens
                                        $$ = (Node *)makeOverlaps($1, $3);
                                }
                        | row IS DISTINCT FROM row
+                       %prec IS
                                {
                                        /* IS DISTINCT FROM has the following rules for non-array types:
                                         * a) the row lengths must be equal
@@ -5736,13 +5744,13 @@ a_expr:         c_expr                                                                  { $$ = $1; }
                                        b->booltesttype = IS_NOT_UNKNOWN;
                                        $$ = (Node *)b;
                                }
-                       | a_expr IS DISTINCT FROM a_expr                        %prec DISTINCT
+                       | a_expr IS DISTINCT FROM a_expr                        %prec IS
                                { $$ = (Node *) makeSimpleA_Expr(DISTINCT, "=", $1, $5); }
-                       | a_expr IS OF '(' type_list ')'
+                       | a_expr IS OF '(' type_list ')'                        %prec IS
                                {
                                        $$ = (Node *) makeSimpleA_Expr(OF, "=", $1, (Node *) $5);
                                }
-                       | a_expr IS NOT OF '(' type_list ')'
+                       | a_expr IS NOT OF '(' type_list ')'            %prec IS
                                {
                                        $$ = (Node *) makeSimpleA_Expr(OF, "!=", $1, (Node *) $6);
                                }
@@ -5890,13 +5898,13 @@ b_expr:         c_expr
                                { $$ = (Node *) makeA_Expr(OP, $1, NULL, $2); }
                        | b_expr qual_Op                                        %prec POSTFIXOP
                                { $$ = (Node *) makeA_Expr(OP, $2, $1, NULL); }
-                       | b_expr IS DISTINCT FROM b_expr        %prec Op
+                       | b_expr IS DISTINCT FROM b_expr        %prec IS
                                { $$ = (Node *) makeSimpleA_Expr(DISTINCT, "=", $1, $5); }
-                       | b_expr IS OF '(' type_list ')'
+                       | b_expr IS OF '(' type_list ')'        %prec IS
                                {
                                        $$ = (Node *) makeSimpleA_Expr(OF, "=", $1, (Node *) $5);
                                }
-                       | b_expr IS NOT OF '(' type_list ')'
+                       | b_expr IS NOT OF '(' type_list ')'    %prec IS
                                {
                                        $$ = (Node *) makeSimpleA_Expr(OF, "!=", $1, (Node *) $6);
                                }