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Commit6b0706a

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Arrange for an explicit cast applied to an ARRAY[] constructor to be applied
directly to all the member expressions, instead of the previous implementationwhere the ARRAY[] constructor would infer a common element type and then we'dcoerce the finished array after the fact. This has a number of benefits,one being that we can allow an empty ARRAY[] construct so long as itselement type is specified by such a cast.Brendan Jurd, minor fixes by me.
1 parent8759b79 commit6b0706a

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11 files changed

+311
-99
lines changed

11 files changed

+311
-99
lines changed

‎doc/src/sgml/syntax.sgml

Lines changed: 35 additions & 7 deletions
Original file line numberDiff line numberDiff line change
@@ -1,4 +1,4 @@
1-
<!-- $PostgreSQL: pgsql/doc/src/sgml/syntax.sgml,v 1.121 2008/01/23 19:51:29 tgl Exp $ -->
1+
<!-- $PostgreSQL: pgsql/doc/src/sgml/syntax.sgml,v 1.122 2008/03/20 21:42:47 tgl Exp $ -->
22

33
<chapter id="sql-syntax">
44
<title>SQL Syntax</title>
@@ -1305,7 +1305,7 @@ sqrt(2)
13051305

13061306
where <replaceable>aggregate_name</replaceable> is a previously
13071307
defined aggregate (possibly qualified with a schema name), and
1308-
<replaceable>expression</replaceable> is
1308+
<replaceable>expression</replaceable> is
13091309
any value expression that does not itself contain an aggregate
13101310
expression.
13111311
</para>
@@ -1335,7 +1335,7 @@ sqrt(2)
13351335
<para>
13361336
The predefined aggregate functions are described in <xref
13371337
linkend="functions-aggregate">. Other aggregate functions can be added
1338-
by the user.
1338+
by the user.
13391339
</para>
13401340

13411341
<para>
@@ -1495,9 +1495,9 @@ SELECT name, (SELECT max(pop) FROM cities WHERE cities.state = states.name)
14951495
<para>
14961496
An array constructor is an expression that builds an
14971497
array value from values for its member elements. A simple array
1498-
constructor
1498+
constructor
14991499
consists of the key word <literal>ARRAY</literal>, a left square bracket
1500-
<literal>[</>,one or more expressions (separated by commas) for the
1500+
<literal>[</>,a list of expressions (separated by commas) for the
15011501
array element values, and finally a right square bracket <literal>]</>.
15021502
For example:
15031503
<programlisting>
@@ -1507,9 +1507,22 @@ SELECT ARRAY[1,2,3+4];
15071507
{1,2,7}
15081508
(1 row)
15091509
</programlisting>
1510-
The array element type is the common type of the member expressions,
1510+
By default,
1511+
the array element type is the common type of the member expressions,
15111512
determined using the same rules as for <literal>UNION</> or
1512-
<literal>CASE</> constructs (see <xref linkend="typeconv-union-case">).
1513+
<literal>CASE</> constructs (see <xref linkend="typeconv-union-case">).
1514+
You can override this by explicitly casting the array constructor to the
1515+
desired type, for example:
1516+
<programlisting>
1517+
SELECT ARRAY[1,2,22.7]::integer[];
1518+
array
1519+
----------
1520+
{1,2,23}
1521+
(1 row)
1522+
</programlisting>
1523+
This has the same effect as casting each expression to the array
1524+
element type individually.
1525+
For more on casting, see <xref linkend="sql-syntax-type-casts">.
15131526
</para>
15141527

15151528
<para>
@@ -1534,6 +1547,8 @@ SELECT ARRAY[[1,2],[3,4]];
15341547

15351548
Since multidimensional arrays must be rectangular, inner constructors
15361549
at the same level must produce sub-arrays of identical dimensions.
1550+
Any cast applied to the outer <literal>ARRAY</> constructor propagates
1551+
automatically to all the inner constructors.
15371552
</para>
15381553

15391554
<para>
@@ -1553,6 +1568,19 @@ SELECT ARRAY[f1, f2, '{{9,10},{11,12}}'::int[]] FROM arr;
15531568
</programlisting>
15541569
</para>
15551570

1571+
<para>
1572+
You can construct an empty array, but since it's impossible to have an
1573+
array with no type, you must explicitly cast your empty array to the
1574+
desired type. For example:
1575+
<programlisting>
1576+
SELECT ARRAY[]::integer[];
1577+
array
1578+
-------
1579+
{}
1580+
(1 row)
1581+
</programlisting>
1582+
</para>
1583+
15561584
<para>
15571585
It is also possible to construct an array from the results of a
15581586
subquery. In this form, the array constructor is written with the

‎src/backend/nodes/copyfuncs.c

Lines changed: 14 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -15,7 +15,7 @@
1515
* Portions Copyright (c) 1994, Regents of the University of California
1616
*
1717
* IDENTIFICATION
18-
* $PostgreSQL: pgsql/src/backend/nodes/copyfuncs.c,v 1.388 2008/02/07 20:19:47 tgl Exp $
18+
* $PostgreSQL: pgsql/src/backend/nodes/copyfuncs.c,v 1.389 2008/03/20 21:42:47 tgl Exp $
1919
*
2020
*-------------------------------------------------------------------------
2121
*/
@@ -1684,6 +1684,16 @@ _copyA_Indirection(A_Indirection *from)
16841684
returnnewnode;
16851685
}
16861686

1687+
staticA_ArrayExpr*
1688+
_copyA_ArrayExpr(A_ArrayExpr*from)
1689+
{
1690+
A_ArrayExpr*newnode=makeNode(A_ArrayExpr);
1691+
1692+
COPY_NODE_FIELD(elements);
1693+
1694+
returnnewnode;
1695+
}
1696+
16871697
staticResTarget*
16881698
_copyResTarget(ResTarget*from)
16891699
{
@@ -3543,6 +3553,9 @@ copyObject(void *from)
35433553
caseT_A_Indirection:
35443554
retval=_copyA_Indirection(from);
35453555
break;
3556+
caseT_A_ArrayExpr:
3557+
retval=_copyA_ArrayExpr(from);
3558+
break;
35463559
caseT_ResTarget:
35473560
retval=_copyResTarget(from);
35483561
break;

‎src/backend/nodes/equalfuncs.c

Lines changed: 12 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -18,7 +18,7 @@
1818
* Portions Copyright (c) 1994, Regents of the University of California
1919
*
2020
* IDENTIFICATION
21-
* $PostgreSQL: pgsql/src/backend/nodes/equalfuncs.c,v 1.318 2008/02/07 20:19:47 tgl Exp $
21+
* $PostgreSQL: pgsql/src/backend/nodes/equalfuncs.c,v 1.319 2008/03/20 21:42:48 tgl Exp $
2222
*
2323
*-------------------------------------------------------------------------
2424
*/
@@ -1729,6 +1729,14 @@ _equalA_Indirection(A_Indirection *a, A_Indirection *b)
17291729
return true;
17301730
}
17311731

1732+
staticbool
1733+
_equalA_ArrayExpr(A_ArrayExpr*a,A_ArrayExpr*b)
1734+
{
1735+
COMPARE_NODE_FIELD(elements);
1736+
1737+
return true;
1738+
}
1739+
17321740
staticbool
17331741
_equalResTarget(ResTarget*a,ResTarget*b)
17341742
{
@@ -2469,6 +2477,9 @@ equal(void *a, void *b)
24692477
caseT_A_Indirection:
24702478
retval=_equalA_Indirection(a,b);
24712479
break;
2480+
caseT_A_ArrayExpr:
2481+
retval=_equalA_ArrayExpr(a,b);
2482+
break;
24722483
caseT_ResTarget:
24732484
retval=_equalResTarget(a,b);
24742485
break;

‎src/backend/nodes/outfuncs.c

Lines changed: 12 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $PostgreSQL: pgsql/src/backend/nodes/outfuncs.c,v 1.322 2008/01/09 08:46:44 neilc Exp $
11+
* $PostgreSQL: pgsql/src/backend/nodes/outfuncs.c,v 1.323 2008/03/20 21:42:48 tgl Exp $
1212
*
1313
* NOTES
1414
* Every node type that can appear in stored rules' parsetrees *must*
@@ -1971,6 +1971,14 @@ _outA_Indirection(StringInfo str, A_Indirection *node)
19711971
WRITE_NODE_FIELD(indirection);
19721972
}
19731973

1974+
staticvoid
1975+
_outA_ArrayExpr(StringInfostr,A_ArrayExpr*node)
1976+
{
1977+
WRITE_NODE_TYPE("A_ARRAYEXPR");
1978+
1979+
WRITE_NODE_FIELD(elements);
1980+
}
1981+
19741982
staticvoid
19751983
_outResTarget(StringInfostr,ResTarget*node)
19761984
{
@@ -2417,6 +2425,9 @@ _outNode(StringInfo str, void *obj)
24172425
caseT_A_Indirection:
24182426
_outA_Indirection(str,obj);
24192427
break;
2428+
caseT_A_ArrayExpr:
2429+
_outA_ArrayExpr(str,obj);
2430+
break;
24202431
caseT_ResTarget:
24212432
_outResTarget(str,obj);
24222433
break;

‎src/backend/parser/gram.y

Lines changed: 43 additions & 42 deletions
Original file line numberDiff line numberDiff line change
@@ -11,7 +11,7 @@
1111
*
1212
*
1313
* IDENTIFICATION
14-
* $PostgreSQL: pgsql/src/backend/parser/gram.y,v 2.608 2008/03/19 18:38:30 tgl Exp $
14+
* $PostgreSQL: pgsql/src/backend/parser/gram.y,v 2.609 2008/03/20 21:42:48 tgl Exp $
1515
*
1616
* HISTORY
1717
* AUTHORDATEMAJOR EVENT
@@ -107,6 +107,7 @@ static void insertSelectOptions(SelectStmt *stmt,
107107
static Node *makeSetOp(SetOperation op,bool all, Node *larg, Node *rarg);
108108
static Node *doNegate(Node *n,int location);
109109
staticvoiddoNegateFloat(Value *v);
110+
static Node *makeAArrayExpr(List *elements);
110111
static Node *makeXmlExpr(XmlExprOp op,char *name, List *named_args, List *args);
111112

112113
%}
@@ -8429,45 +8430,43 @@ expr_list:a_expr
84298430
}
84308431
;
84318432

8432-
extract_list:
8433-
extract_arg FROM a_expr
8434-
{
8435-
A_Const *n = makeNode(A_Const);
8436-
n->val.type = T_String;
8437-
n->val.val.str =$1;
8438-
$$ = list_make2((Node *) n,$3);
8439-
}
8440-
|/*EMPTY*/{$$ = NIL; }
8441-
;
8442-
84438433
type_list:Typename{$$ = list_make1($1); }
84448434
| type_list',' Typename{$$ = lappend($1,$3); }
84458435
;
84468436

8447-
array_expr_list: array_expr
8448-
{$$ = list_make1($1);}
8449-
| array_expr_list',' array_expr
8450-
{$$ = lappend($1,$3);}
8451-
;
8452-
84538437
array_expr:'[' expr_list']'
84548438
{
8455-
ArrayExpr *n = makeNode(ArrayExpr);
8456-
n->elements =$2;
8457-
$$ = (Node *)n;
8439+
$$ = makeAArrayExpr($2);
84588440
}
84598441
|'[' array_expr_list']'
84608442
{
8461-
ArrayExpr *n = makeNode(ArrayExpr);
8462-
n->elements =$2;
8463-
$$ = (Node *)n;
8443+
$$ = makeAArrayExpr($2);
8444+
}
8445+
|'['']'
8446+
{
8447+
$$ = makeAArrayExpr(NIL);
8448+
}
8449+
;
8450+
8451+
array_expr_list: array_expr{$$ = list_make1($1); }
8452+
| array_expr_list',' array_expr{$$ = lappend($1,$3); }
8453+
;
8454+
8455+
8456+
extract_list:
8457+
extract_arg FROM a_expr
8458+
{
8459+
A_Const *n = makeNode(A_Const);
8460+
n->val.type = T_String;
8461+
n->val.val.str =$1;
8462+
$$ = list_make2((Node *) n,$3);
84648463
}
8464+
|/*EMPTY*/{$$ = NIL; }
84658465
;
84668466

84678467
/* Allow delimited string SCONST in extract_arg as an SQL extension.
84688468
* - thomas 2001-04-12
84698469
*/
8470-
84718470
extract_arg:
84728471
IDENT{$$ =$1; }
84738472
| YEAR_P{$$ ="year"; }
@@ -9502,13 +9501,6 @@ makeColumnRef(char *relname, List *indirection, int location)
95029501
static Node *
95039502
makeTypeCast(Node *arg, TypeName *typename)
95049503
{
9505-
/*
9506-
* Simply generate a TypeCast node.
9507-
*
9508-
* Earlier we would determine whether an A_Const would
9509-
* be acceptable, however Domains require coerce_type()
9510-
* to process them -- applying constraints as required.
9511-
*/
95129504
TypeCast *n = makeNode(TypeCast);
95139505
n->arg = arg;
95149506
n->typename = typename;
@@ -9582,7 +9574,7 @@ makeBoolAConst(bool state)
95829574
{
95839575
A_Const *n = makeNode(A_Const);
95849576
n->val.type = T_String;
9585-
n->val.val.str = (state? "t": "f");
9577+
n->val.val.str = (state? "t": "f");
95869578
n->typename = SystemTypeName("bool");
95879579
return n;
95889580
}
@@ -9763,15 +9755,6 @@ SystemTypeName(char *name)
97639755
makeString(name)));
97649756
}
97659757

9766-
/* parser_init()
9767-
* Initialize to parse one query string
9768-
*/
9769-
void
9770-
parser_init(void)
9771-
{
9772-
QueryIsRule = FALSE;
9773-
}
9774-
97759758
/* doNegate()
97769759
* Handle negation of a numeric constant.
97779760
*
@@ -9827,6 +9810,15 @@ doNegateFloat(Value *v)
98279810
}
98289811
}
98299812

9813+
static Node *
9814+
makeAArrayExpr(List *elements)
9815+
{
9816+
A_ArrayExpr *n = makeNode(A_ArrayExpr);
9817+
9818+
n->elements = elements;
9819+
return (Node *) n;
9820+
}
9821+
98309822
static Node *
98319823
makeXmlExpr(XmlExprOp op, char *name, List *named_args, List *args)
98329824
{
@@ -9844,6 +9836,15 @@ makeXmlExpr(XmlExprOp op, char *name, List *named_args, List *args)
98449836
return (Node *) x;
98459837
}
98469838

9839+
/* parser_init()
9840+
* Initialize to parse one query string
9841+
*/
9842+
void
9843+
parser_init(void)
9844+
{
9845+
QueryIsRule = FALSE;
9846+
}
9847+
98479848
/*
98489849
* Must undefine base_yylex before including scan.c, since we want it
98499850
* to create the function base_yylex not filtered_base_yylex.

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