From 6fe27ca2fb20b67736d7af3acec08ed64488ab44 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Thu, 5 Sep 2002 22:52:48 +0000
Subject: [PATCH] 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.
---
src/backend/parser/gram.y | 26 +++++++++++++++++---------
1 file changed, 17 insertions(+), 9 deletions(-)
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 674a6d0d920..d038cdd46e7 100644
--- 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);
}
--
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