From ea4ae108493a6e2e4f975248907686277e68e9d9 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Sat, 20 Nov 1999 21:39:36 +0000
Subject: [PATCH] Fix problems with CURRENT_DATE and related functions being
used in table defaults or rules: translate them to a function call so that
parse_coerce doesn't reduce them to a date or time constant immediately.
Also, eliminate a lot of redundancy in the expression grammar by defining a
new nonterminal com_expr, which contains all the productions that can be
shared by a_expr and b_expr.
---
src/backend/parser/gram.y | 631 +++++++++++++++-----------------------
1 file changed, 253 insertions(+), 378 deletions(-)
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 9aa9f93cd15..5a291dc867f 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -10,7 +10,7 @@
*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 2.114 1999/11/15 02:00:10 tgl Exp $
+ * $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 2.115 1999/11/20 21:39:36 tgl Exp $
*
* HISTORY
* AUTHOR DATE MAJOR EVENT
@@ -212,11 +212,10 @@ static Node *doNegate(Node *n);
%type <node> columnDef, alter_clause
%type <defelt> def_elem
%type <node> def_arg, columnElem, where_clause,
- a_expr, a_expr_or_null, b_expr, AexprConst,
+ a_expr, a_expr_or_null, b_expr, com_expr, AexprConst,
in_expr, having_clause
%type <list> row_descriptor, row_list, in_expr_nodes
%type <node> row_expr
-%type <str> row_op
%type <node> case_expr, case_arg, when_clause, case_default
%type <list> when_clause_list
%type <ival> sub_type
@@ -942,15 +941,18 @@ ColConstraint:
{ $$ = $1; }
;
-/* DEFAULT NULL is already the default for Postgres.
+/*
+ * DEFAULT NULL is already the default for Postgres.
* But define it here and carry it forward into the system
* to make it explicit.
* - thomas 1998-09-13
+ *
* WITH NULL and NULL are not SQL92-standard syntax elements,
* so leave them out. Use DEFAULT NULL to explicitly indicate
* that a column may have that value. WITH NULL leads to
* shift/reduce conflicts with WITH TIME ZONE anyway.
* - thomas 1999-01-08
+ *
* DEFAULT expression must be b_expr not a_expr to prevent shift/reduce
* conflict on NOT (since NOT might start a subsequent NOT NULL constraint,
* or be part of a_expr NOT LIKE or similar constructs).
@@ -1466,8 +1468,7 @@ def_type: OPERATOR { $$ = OPERATOR; }
def_name: PROCEDURE { $$ = "procedure"; }
| JOIN { $$ = "join"; }
| ColId { $$ = $1; }
- | MathOp { $$ = $1; }
- | Op { $$ = $1; }
+ | all_Op { $$ = $1; }
;
definition: '(' def_list ')' { $$ = $2; }
@@ -2065,20 +2066,6 @@ RemoveOperStmt: DROP OPERATOR all_Op '(' oper_argtypes ')'
}
;
-all_Op: Op | MathOp;
-
-MathOp: '+' { $$ = "+"; }
- | '-' { $$ = "-"; }
- | '*' { $$ = "*"; }
- | '/' { $$ = "/"; }
- | '%' { $$ = "%"; }
- | '^' { $$ = "^"; }
- | '|' { $$ = "|"; }
- | '<' { $$ = "<"; }
- | '>' { $$ = ">"; }
- | '=' { $$ = "="; }
- ;
-
oper_argtypes: name
{
elog(ERROR,"parser: argument type missing (use NONE for unary operators)");
@@ -2951,9 +2938,7 @@ sortby: a_expr OptUseOp
}
;
-OptUseOp: USING Op { $$ = $2; }
- | USING '<' { $$ = "<"; }
- | USING '>' { $$ = ">"; }
+OptUseOp: USING all_Op { $$ = $2; }
| ASC { $$ = "<"; }
| DESC { $$ = ">"; }
| /*EMPTY*/ { $$ = "<"; /*default*/ }
@@ -3578,7 +3563,7 @@ opt_interval: datetime { $$ = lcons($1, NIL); }
/*****************************************************************************
*
- * expression grammar, still needs some cleanup
+ * expression grammar
*
*****************************************************************************/
@@ -3595,8 +3580,6 @@ a_expr_or_null: a_expr
/* Expressions using row descriptors
* Define row_descriptor to allow yacc to break the reduce/reduce conflict
* with singleton expressions.
- * Eliminated lots of code by defining row_op and sub_type clauses.
- * - thomas 1998-05-09
*/
row_expr: '(' row_descriptor ')' IN '(' SubSelect ')'
{
@@ -3618,7 +3601,7 @@ row_expr: '(' row_descriptor ')' IN '(' SubSelect ')'
n->subselect = $7;
$$ = (Node *)n;
}
- | '(' row_descriptor ')' row_op sub_type '(' SubSelect ')'
+ | '(' row_descriptor ')' all_Op sub_type '(' SubSelect ')'
{
SubLink *n = makeNode(SubLink);
n->lefthand = $2;
@@ -3631,7 +3614,7 @@ row_expr: '(' row_descriptor ')' IN '(' SubSelect ')'
n->subselect = $7;
$$ = (Node *)n;
}
- | '(' row_descriptor ')' row_op '(' SubSelect ')'
+ | '(' row_descriptor ')' all_Op '(' SubSelect ')'
{
SubLink *n = makeNode(SubLink);
n->lefthand = $2;
@@ -3644,7 +3627,7 @@ row_expr: '(' row_descriptor ')' IN '(' SubSelect ')'
n->subselect = $6;
$$ = (Node *)n;
}
- | '(' row_descriptor ')' row_op '(' row_descriptor ')'
+ | '(' row_descriptor ')' all_Op '(' row_descriptor ')'
{
$$ = makeRowExpr($4, $2, $6);
}
@@ -3666,45 +3649,67 @@ row_list: row_list ',' a_expr
}
;
-row_op: Op { $$ = $1; }
- | '<' { $$ = "<"; }
- | '=' { $$ = "="; }
- | '>' { $$ = ">"; }
- | '+' { $$ = "+"; }
- | '-' { $$ = "-"; }
- | '*' { $$ = "*"; }
- | '/' { $$ = "/"; }
- | '%' { $$ = "%"; }
- | '^' { $$ = "^"; }
- | '|' { $$ = "|"; }
- ;
-
sub_type: ANY { $$ = ANY_SUBLINK; }
| ALL { $$ = ALL_SUBLINK; }
;
-/* General expressions
+all_Op: Op | MathOp;
+
+MathOp: '+' { $$ = "+"; }
+ | '-' { $$ = "-"; }
+ | '*' { $$ = "*"; }
+ | '/' { $$ = "/"; }
+ | '%' { $$ = "%"; }
+ | '^' { $$ = "^"; }
+ | '|' { $$ = "|"; }
+ | '<' { $$ = "<"; }
+ | '>' { $$ = ">"; }
+ | '=' { $$ = "="; }
+ ;
+
+/*
+ * General expressions
* This is the heart of the expression syntax.
- * Note that the BETWEEN clause looks similar to a boolean expression
- * and so we must define b_expr which is almost the same as a_expr
- * but without the boolean expressions.
- * All operations/expressions are allowed in a BETWEEN clause
- * if surrounded by parens.
+ *
+ * We have two expression types: a_expr is the unrestricted kind, and
+ * b_expr is a subset that must be used in some places to avoid shift/reduce
+ * conflicts. For example, we can't do BETWEEN as "BETWEEN a_expr AND a_expr"
+ * because that use of AND conflicts with AND as a boolean operator. So,
+ * b_expr is used in BETWEEN and we remove boolean keywords from b_expr.
+ *
+ * Note that '(' a_expr ')' is a b_expr, so an unrestricted expression can
+ * always be used by surrounding it with parens.
+ *
+ * com_expr is all the productions that are common to a_expr and b_expr;
+ * it's factored out just to eliminate redundant coding.
*/
-a_expr: attr
- { $$ = (Node *) $1; }
- | row_expr
+a_expr: com_expr
{ $$ = $1; }
- | AexprConst
- { $$ = $1; }
- | ColId opt_indirection
+ | a_expr TYPECAST Typename
{
- /* could be a column name or a relation_name */
- Ident *n = makeNode(Ident);
- n->name = $1;
- n->indirection = $2;
- $$ = (Node *)n;
+ $$ = (Node *)$1;
+ /* AexprConst can be either A_Const or ParamNo */
+ if (nodeTag($1) == T_A_Const) {
+ ((A_Const *)$1)->typename = $3;
+ } else if (nodeTag($1) == T_ParamNo) {
+ ((ParamNo *)$1)->typename = $3;
+ /* otherwise, try to transform to a function call */
+ } else {
+ FuncCall *n = makeNode(FuncCall);
+ n->funcname = $3->name;
+ n->args = lcons($1,NIL);
+ $$ = (Node *)n;
+ }
}
+ /*
+ * These operators must be called out explicitly in order to make use
+ * of yacc/bison's automatic operator-precedence handling. All other
+ * operator names are handled by the generic productions using "Op",
+ * below; and all those operators will have the same precedence.
+ *
+ * If you add more explicitly-known operators, be sure to add them
+ * also to b_expr and to the MathOp list above.
+ */
| '-' a_expr %prec UMINUS
{ $$ = doNegate($2); }
| '%' a_expr
@@ -3750,242 +3755,26 @@ a_expr: attr
| a_expr '=' a_expr
{ $$ = makeA_Expr(OP, "=", $1, $3); }
- | a_expr TYPECAST Typename
- {
- $$ = (Node *)$1;
- /* AexprConst can be either A_Const or ParamNo */
- if (nodeTag($1) == T_A_Const) {
- ((A_Const *)$1)->typename = $3;
- } else if (nodeTag($1) == T_ParamNo) {
- ((ParamNo *)$1)->typename = $3;
- /* otherwise, try to transform to a function call */
- } else {
- FuncCall *n = makeNode(FuncCall);
- n->funcname = $3->name;
- n->args = lcons($1,NIL);
- $$ = (Node *)n;
- }
- }
- | CAST '(' a_expr AS Typename ')'
- {
- $$ = (Node *)$3;
- /* AexprConst can be either A_Const or ParamNo */
- if (nodeTag($3) == T_A_Const) {
- ((A_Const *)$3)->typename = $5;
- } else if (nodeTag($3) == T_ParamNo) {
- ((ParamNo *)$3)->typename = $5;
- /* otherwise, try to transform to a function call */
- } else {
- FuncCall *n = makeNode(FuncCall);
- n->funcname = $5->name;
- n->args = lcons($3,NIL);
- $$ = (Node *)n;
- }
- }
- | '(' a_expr_or_null ')'
- { $$ = $2; }
+
| a_expr Op a_expr
- { $$ = makeA_Expr(OP, $2, $1, $3); }
- | a_expr LIKE a_expr
- { $$ = makeA_Expr(OP, "~~", $1, $3); }
- | a_expr NOT LIKE a_expr
- { $$ = makeA_Expr(OP, "!~~", $1, $4); }
+ { $$ = makeA_Expr(OP, $2, $1, $3); }
| Op a_expr
{ $$ = makeA_Expr(OP, $1, NULL, $2); }
| a_expr Op
{ $$ = makeA_Expr(OP, $2, $1, NULL); }
- | func_name '(' '*' ')'
- {
- /*
- * For now, we transform AGGREGATE(*) into AGGREGATE(1).
- *
- * This does the right thing for COUNT(*) (in fact,
- * any certainly-non-null expression would do for COUNT),
- * and there are no other aggregates in SQL92 that accept
- * '*' as parameter.
- *
- * XXX really, the '*' ought to be transformed to some
- * special construct that wouldn't be acceptable as the
- * input of a non-aggregate function, in case the given
- * func_name matches a plain function. This would also
- * support a possible extension to let user-defined
- * aggregates do something special with '*' as input.
- */
- FuncCall *n = makeNode(FuncCall);
- A_Const *star = makeNode(A_Const);
- star->val.type = T_Integer;
- star->val.val.ival = 1;
- n->funcname = $1;
- n->args = lcons(star, NIL);
- $$ = (Node *)n;
- }
- | func_name '(' ')'
- {
- FuncCall *n = makeNode(FuncCall);
- n->funcname = $1;
- n->args = NIL;
- $$ = (Node *)n;
- }
- | func_name '(' expr_list ')'
- {
- FuncCall *n = makeNode(FuncCall);
- n->funcname = $1;
- n->args = $3;
- $$ = (Node *)n;
- }
- | CURRENT_DATE
- {
- A_Const *n = makeNode(A_Const);
- TypeName *t = makeNode(TypeName);
-
- n->val.type = T_String;
- n->val.val.str = "now";
- n->typename = t;
-
- t->name = xlateSqlType("date");
- t->setof = FALSE;
- t->typmod = -1;
-
- $$ = (Node *)n;
- }
- | CURRENT_TIME
- {
- A_Const *n = makeNode(A_Const);
- TypeName *t = makeNode(TypeName);
-
- n->val.type = T_String;
- n->val.val.str = "now";
- n->typename = t;
-
- t->name = xlateSqlType("time");
- t->setof = FALSE;
- t->typmod = -1;
-
- $$ = (Node *)n;
- }
- | CURRENT_TIME '(' Iconst ')'
- {
- FuncCall *n = makeNode(FuncCall);
- A_Const *s = makeNode(A_Const);
- TypeName *t = makeNode(TypeName);
-
- n->funcname = xlateSqlType("time");
- n->args = lcons(s, NIL);
-
- s->val.type = T_String;
- s->val.val.str = "now";
- s->typename = t;
-
- t->name = xlateSqlType("time");
- t->setof = FALSE;
- t->typmod = -1;
-
- if ($3 != 0)
- elog(NOTICE,"CURRENT_TIME(%d) precision not implemented; zero used instead",$3);
-
- $$ = (Node *)n;
- }
- | CURRENT_TIMESTAMP
- {
- A_Const *n = makeNode(A_Const);
- TypeName *t = makeNode(TypeName);
-
- n->val.type = T_String;
- n->val.val.str = "now";
- n->typename = t;
-
- t->name = xlateSqlType("timestamp");
- t->setof = FALSE;
- t->typmod = -1;
-
- $$ = (Node *)n;
- }
- | CURRENT_TIMESTAMP '(' Iconst ')'
- {
- FuncCall *n = makeNode(FuncCall);
- A_Const *s = makeNode(A_Const);
- TypeName *t = makeNode(TypeName);
- n->funcname = xlateSqlType("timestamp");
- n->args = lcons(s, NIL);
-
- s->val.type = T_String;
- s->val.val.str = "now";
- s->typename = t;
-
- t->name = xlateSqlType("timestamp");
- t->setof = FALSE;
- t->typmod = -1;
+ | a_expr AND a_expr
+ { $$ = makeA_Expr(AND, NULL, $1, $3); }
+ | a_expr OR a_expr
+ { $$ = makeA_Expr(OR, NULL, $1, $3); }
+ | NOT a_expr
+ { $$ = makeA_Expr(NOT, NULL, NULL, $2); }
- if ($3 != 0)
- elog(NOTICE,"CURRENT_TIMESTAMP(%d) precision not implemented; zero used instead",$3);
+ | a_expr LIKE a_expr
+ { $$ = makeA_Expr(OP, "~~", $1, $3); }
+ | a_expr NOT LIKE a_expr
+ { $$ = makeA_Expr(OP, "!~~", $1, $4); }
- $$ = (Node *)n;
- }
- | CURRENT_USER
- {
- FuncCall *n = makeNode(FuncCall);
- n->funcname = "getpgusername";
- n->args = NIL;
- $$ = (Node *)n;
- }
- | USER
- {
- FuncCall *n = makeNode(FuncCall);
- n->funcname = "getpgusername";
- n->args = NIL;
- $$ = (Node *)n;
- }
- | EXTRACT '(' extract_list ')'
- {
- FuncCall *n = makeNode(FuncCall);
- n->funcname = "date_part";
- n->args = $3;
- $$ = (Node *)n;
- }
- | POSITION '(' position_list ')'
- {
- FuncCall *n = makeNode(FuncCall);
- n->funcname = "strpos";
- n->args = $3;
- $$ = (Node *)n;
- }
- | SUBSTRING '(' substr_list ')'
- {
- FuncCall *n = makeNode(FuncCall);
- n->funcname = "substr";
- n->args = $3;
- $$ = (Node *)n;
- }
- /* various trim expressions are defined in SQL92 - thomas 1997-07-19 */
- | TRIM '(' BOTH trim_list ')'
- {
- FuncCall *n = makeNode(FuncCall);
- n->funcname = "btrim";
- n->args = $4;
- $$ = (Node *)n;
- }
- | TRIM '(' LEADING trim_list ')'
- {
- FuncCall *n = makeNode(FuncCall);
- n->funcname = "ltrim";
- n->args = $4;
- $$ = (Node *)n;
- }
- | TRIM '(' TRAILING trim_list ')'
- {
- FuncCall *n = makeNode(FuncCall);
- n->funcname = "rtrim";
- n->args = $4;
- $$ = (Node *)n;
- }
- | TRIM '(' trim_list ')'
- {
- FuncCall *n = makeNode(FuncCall);
- n->funcname = "btrim";
- n->args = $3;
- $$ = (Node *)n;
- }
| a_expr ISNULL
{ $$ = makeA_Expr(ISNULL, NULL, $1, NULL); }
| a_expr IS NULL_P
@@ -4105,7 +3894,7 @@ a_expr: attr
$$ = n;
}
}
- | a_expr row_op sub_type '(' SubSelect ')'
+ | a_expr all_Op sub_type '(' SubSelect ')'
{
SubLink *n = makeNode(SubLink);
n->lefthand = lcons($1, NIL);
@@ -4115,53 +3904,36 @@ a_expr: attr
n->subselect = $5;
$$ = (Node *)n;
}
- | EXISTS '(' SubSelect ')'
- {
- SubLink *n = makeNode(SubLink);
- n->lefthand = NIL;
- n->oper = NIL;
- n->useor = false;
- n->subLinkType = EXISTS_SUBLINK;
- n->subselect = $3;
- $$ = (Node *)n;
- }
- | '(' SubSelect ')'
- {
- SubLink *n = makeNode(SubLink);
- n->lefthand = NIL;
- n->oper = NIL;
- n->useor = false;
- n->subLinkType = EXPR_SUBLINK;
- n->subselect = $2;
- $$ = (Node *)n;
- }
- | a_expr AND a_expr
- { $$ = makeA_Expr(AND, NULL, $1, $3); }
- | a_expr OR a_expr
- { $$ = makeA_Expr(OR, NULL, $1, $3); }
- | NOT a_expr
- { $$ = makeA_Expr(NOT, NULL, NULL, $2); }
- | case_expr
- { $$ = $1; }
+ | row_expr
+ { $$ = $1; }
;
-/* Restricted expressions
- * b_expr is a subset of the complete expression syntax
- * defined by a_expr. b_expr is used in BETWEEN clauses
- * to eliminate parser ambiguities stemming from the AND keyword,
- * and also in POSITION clauses where the IN keyword gives trouble.
+/*
+ * Restricted expressions
+ *
+ * b_expr is a subset of the complete expression syntax defined by a_expr.
+ *
+ * Presently, AND, NOT, IS, IN, and NULL are the a_expr keywords that would
+ * cause trouble in the places where b_expr is used. For simplicity, we
+ * just eliminate all the boolean-keyword-operator productions from b_expr.
*/
-b_expr: attr
- { $$ = (Node *) $1; }
- | AexprConst
+b_expr: com_expr
{ $$ = $1; }
- | ColId opt_indirection
+ | b_expr TYPECAST Typename
{
- /* could be a column name or a relation_name */
- Ident *n = makeNode(Ident);
- n->name = $1;
- n->indirection = $2;
- $$ = (Node *)n;
+ $$ = (Node *)$1;
+ /* AexprConst can be either A_Const or ParamNo */
+ if (nodeTag($1) == T_A_Const) {
+ ((A_Const *)$1)->typename = $3;
+ } else if (nodeTag($1) == T_ParamNo) {
+ ((ParamNo *)$1)->typename = $3;
+ /* otherwise, try to transform to a function call */
+ } else {
+ FuncCall *n = makeNode(FuncCall);
+ n->funcname = $3->name;
+ n->args = lcons($1,NIL);
+ $$ = (Node *)n;
+ }
}
| '-' b_expr %prec UMINUS
{ $$ = doNegate($2); }
@@ -4195,23 +3967,44 @@ b_expr: attr
{ $$ = makeA_Expr(OP, "^", $1, $3); }
| b_expr '|' b_expr
{ $$ = makeA_Expr(OP, "|", $1, $3); }
- | b_expr TYPECAST Typename
+ | b_expr '<' b_expr
+ { $$ = makeA_Expr(OP, "<", $1, $3); }
+ | b_expr '>' b_expr
+ { $$ = makeA_Expr(OP, ">", $1, $3); }
+ | b_expr '=' b_expr
+ { $$ = makeA_Expr(OP, "=", $1, $3); }
+
+ | b_expr Op b_expr
+ { $$ = makeA_Expr(OP, $2, $1, $3); }
+ | Op b_expr
+ { $$ = makeA_Expr(OP, $1, NULL, $2); }
+ | b_expr Op
+ { $$ = makeA_Expr(OP, $2, $1, NULL); }
+ ;
+
+/*
+ * Productions that can be used in both a_expr and b_expr.
+ *
+ * Note: productions that refer recursively to a_expr or b_expr mostly
+ * cannot appear here. However, it's OK to refer to a_exprs that occur
+ * inside parentheses, such as function arguments; that cannot introduce
+ * ambiguity to the b_expr syntax.
+ */
+com_expr: attr
+ { $$ = (Node *) $1; }
+ | ColId opt_indirection
{
- $$ = (Node *)$1;
- /* AexprConst can be either A_Const or ParamNo */
- if (nodeTag($1) == T_A_Const) {
- ((A_Const *)$1)->typename = $3;
- } else if (nodeTag($1) == T_ParamNo) {
- ((ParamNo *)$1)->typename = $3;
- /* otherwise, try to transform to a function call */
- } else {
- FuncCall *n = makeNode(FuncCall);
- n->funcname = $3->name;
- n->args = lcons($1,NIL);
- $$ = (Node *)n;
- }
+ /* could be a column name or a relation_name */
+ Ident *n = makeNode(Ident);
+ n->name = $1;
+ n->indirection = $2;
+ $$ = (Node *)n;
}
- | CAST '(' b_expr AS Typename ')'
+ | AexprConst
+ { $$ = $1; }
+ | '(' a_expr_or_null ')'
+ { $$ = $2; }
+ | CAST '(' a_expr AS Typename ')'
{
$$ = (Node *)$3;
/* AexprConst can be either A_Const or ParamNo */
@@ -4227,14 +4020,8 @@ b_expr: attr
$$ = (Node *)n;
}
}
- | '(' a_expr ')'
- { $$ = $2; }
- | b_expr Op b_expr
- { $$ = makeA_Expr(OP, $2,$1,$3); }
- | Op b_expr
- { $$ = makeA_Expr(OP, $1, NULL, $2); }
- | b_expr Op
- { $$ = makeA_Expr(OP, $2, $1, NULL); }
+ | case_expr
+ { $$ = $1; }
| func_name '(' ')'
{
FuncCall *n = makeNode(FuncCall);
@@ -4249,53 +4036,108 @@ b_expr: attr
n->args = $3;
$$ = (Node *)n;
}
+ | func_name '(' '*' ')'
+ {
+ /*
+ * For now, we transform AGGREGATE(*) into AGGREGATE(1).
+ *
+ * This does the right thing for COUNT(*) (in fact,
+ * any certainly-non-null expression would do for COUNT),
+ * and there are no other aggregates in SQL92 that accept
+ * '*' as parameter.
+ *
+ * XXX really, the '*' ought to be transformed to some
+ * special construct that wouldn't be acceptable as the
+ * input of a non-aggregate function, in case the given
+ * func_name matches a plain function. This would also
+ * support a possible extension to let user-defined
+ * aggregates do something special with '*' as input.
+ */
+ FuncCall *n = makeNode(FuncCall);
+ A_Const *star = makeNode(A_Const);
+
+ star->val.type = T_Integer;
+ star->val.val.ival = 1;
+ n->funcname = $1;
+ n->args = lcons(star, NIL);
+ $$ = (Node *)n;
+ }
| CURRENT_DATE
{
- A_Const *n = makeNode(A_Const);
+ /*
+ * Translate as "date('now'::text)".
+ *
+ * We cannot use "'now'::date" because coerce_type() will
+ * immediately reduce that to a constant representing
+ * today's date. We need to delay the conversion until
+ * runtime, else the wrong things will happen when
+ * CURRENT_DATE is used in a column default value or rule.
+ *
+ * This could be simplified if we had a way to generate
+ * an expression tree representing runtime application
+ * of type-input conversion functions...
+ */
+ A_Const *s = makeNode(A_Const);
TypeName *t = makeNode(TypeName);
+ FuncCall *n = makeNode(FuncCall);
- n->val.type = T_String;
- n->val.val.str = "now";
- n->typename = t;
+ s->val.type = T_String;
+ s->val.val.str = "now";
+ s->typename = t;
- t->name = xlateSqlType("date");
+ t->name = xlateSqlType("text");
t->setof = FALSE;
t->typmod = -1;
+ n->funcname = xlateSqlType("date");
+ n->args = lcons(s, NIL);
+
$$ = (Node *)n;
}
| CURRENT_TIME
{
- A_Const *n = makeNode(A_Const);
+ /*
+ * Translate as "time('now'::text)".
+ * See comments for CURRENT_DATE.
+ */
+ A_Const *s = makeNode(A_Const);
TypeName *t = makeNode(TypeName);
+ FuncCall *n = makeNode(FuncCall);
- n->val.type = T_String;
- n->val.val.str = "now";
- n->typename = t;
+ s->val.type = T_String;
+ s->val.val.str = "now";
+ s->typename = t;
- t->name = xlateSqlType("time");
+ t->name = xlateSqlType("text");
t->setof = FALSE;
t->typmod = -1;
+ n->funcname = xlateSqlType("time");
+ n->args = lcons(s, NIL);
+
$$ = (Node *)n;
}
| CURRENT_TIME '(' Iconst ')'
{
- FuncCall *n = makeNode(FuncCall);
+ /*
+ * Translate as "time('now'::text)".
+ * See comments for CURRENT_DATE.
+ */
A_Const *s = makeNode(A_Const);
TypeName *t = makeNode(TypeName);
-
- n->funcname = xlateSqlType("time");
- n->args = lcons(s, NIL);
+ FuncCall *n = makeNode(FuncCall);
s->val.type = T_String;
s->val.val.str = "now";
s->typename = t;
- t->name = xlateSqlType("time");
+ t->name = xlateSqlType("text");
t->setof = FALSE;
t->typmod = -1;
+ n->funcname = xlateSqlType("time");
+ n->args = lcons(s, NIL);
+
if ($3 != 0)
elog(NOTICE,"CURRENT_TIME(%d) precision not implemented; zero used instead",$3);
@@ -4303,36 +4145,48 @@ b_expr: attr
}
| CURRENT_TIMESTAMP
{
- A_Const *n = makeNode(A_Const);
+ /*
+ * Translate as "timestamp('now'::text)".
+ * See comments for CURRENT_DATE.
+ */
+ A_Const *s = makeNode(A_Const);
TypeName *t = makeNode(TypeName);
+ FuncCall *n = makeNode(FuncCall);
- n->val.type = T_String;
- n->val.val.str = "now";
- n->typename = t;
+ s->val.type = T_String;
+ s->val.val.str = "now";
+ s->typename = t;
- t->name = xlateSqlType("timestamp");
+ t->name = xlateSqlType("text");
t->setof = FALSE;
t->typmod = -1;
+ n->funcname = xlateSqlType("timestamp");
+ n->args = lcons(s, NIL);
+
$$ = (Node *)n;
}
| CURRENT_TIMESTAMP '(' Iconst ')'
{
- FuncCall *n = makeNode(FuncCall);
+ /*
+ * Translate as "timestamp('now'::text)".
+ * See comments for CURRENT_DATE.
+ */
A_Const *s = makeNode(A_Const);
TypeName *t = makeNode(TypeName);
-
- n->funcname = xlateSqlType("timestamp");
- n->args = lcons(s, NIL);
+ FuncCall *n = makeNode(FuncCall);
s->val.type = T_String;
s->val.val.str = "now";
s->typename = t;
- t->name = xlateSqlType("timestamp");
+ t->name = xlateSqlType("text");
t->setof = FALSE;
t->typmod = -1;
+ n->funcname = xlateSqlType("timestamp");
+ n->args = lcons(s, NIL);
+
if ($3 != 0)
elog(NOTICE,"CURRENT_TIMESTAMP(%d) precision not implemented; zero used instead",$3);
@@ -4352,6 +4206,13 @@ b_expr: attr
n->args = NIL;
$$ = (Node *)n;
}
+ | EXTRACT '(' extract_list ')'
+ {
+ FuncCall *n = makeNode(FuncCall);
+ n->funcname = "date_part";
+ n->args = $3;
+ $$ = (Node *)n;
+ }
| POSITION '(' position_list ')'
{
FuncCall *n = makeNode(FuncCall);
@@ -4405,8 +4266,22 @@ b_expr: attr
n->subselect = $2;
$$ = (Node *)n;
}
+ | EXISTS '(' SubSelect ')'
+ {
+ SubLink *n = makeNode(SubLink);
+ n->lefthand = NIL;
+ n->oper = NIL;
+ n->useor = false;
+ n->subLinkType = EXISTS_SUBLINK;
+ n->subselect = $3;
+ $$ = (Node *)n;
+ }
;
+/*
+ * Supporting nonterminals for expressions.
+ */
+
opt_indirection: '[' a_expr ']' opt_indirection
{
A_Indices *ai = makeNode(A_Indices);
--
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