Here is a patch to reimplement the xmlconcat functionality as a variadic
function instead of a hardcoded special expression type. I haven't
found any variadic function in the set of built-in functions so far, so
I figured I would ask for feedback before we go down this route.
Btw., the corresponding ecpg changes appear to have fallen into place
automatically. Nice.
Index: src/backend/executor/execQual.c
===================================================================
RCS file: /cvsroot/pgsql/src/backend/executor/execQual.c,v
retrieving revision 1.237
diff -u -3 -p -c -r1.237 execQual.c
*** src/backend/executor/execQual.c 15 Nov 2008 20:52:35 -0000 1.237
--- src/backend/executor/execQual.c 17 Nov 2008 11:17:09 -0000
*************** ExecEvalXml(XmlExprState *xmlExpr, ExprC
*** 3174,3202 ****
switch (xexpr->op)
{
- case IS_XMLCONCAT:
- {
- List *values = NIL;
-
- foreach(arg, xmlExpr->args)
- {
- ExprState *e = (ExprState *)
lfirst(arg);
-
- value = ExecEvalExpr(e, econtext,
&isnull, NULL);
- if (!isnull)
- values = lappend(values,
DatumGetPointer(value));
- }
-
- if (list_length(values) > 0)
- {
- *isNull = false;
- return
PointerGetDatum(xmlconcat(values));
- }
- else
- return (Datum) 0;
- }
- break;
-
case IS_XMLFOREST:
{
StringInfoData buf;
--- 3174,3179 ----
Index: src/backend/parser/gram.y
===================================================================
RCS file: /cvsroot/pgsql/src/backend/parser/gram.y,v
retrieving revision 2.637
diff -u -3 -p -c -r2.637 gram.y
*** src/backend/parser/gram.y 13 Nov 2008 11:10:06 -0000 2.637
--- src/backend/parser/gram.y 17 Nov 2008 11:17:09 -0000
*************** static TypeName *TableFuncTypeName(List
*** 474,480 ****
WHEN WHERE WHITESPACE_P WITH WITHOUT WORK WRITE
! XML_P XMLATTRIBUTES XMLCONCAT XMLELEMENT XMLFOREST XMLPARSE
XMLPI XMLROOT XMLSERIALIZE
YEAR_P YES_P
--- 474,480 ----
WHEN WHERE WHITESPACE_P WITH WITHOUT WORK WRITE
! XML_P XMLATTRIBUTES XMLELEMENT XMLFOREST XMLPARSE
XMLPI XMLROOT XMLSERIALIZE
YEAR_P YES_P
*************** func_expr: func_name '(' ')'
*** 8620,8629 ****
v->location = @1;
$$ = (Node *)v;
}
- | XMLCONCAT '(' expr_list ')'
- {
- $$ = makeXmlExpr(IS_XMLCONCAT, NULL,
NIL, $3, @1);
- }
| XMLELEMENT '(' NAME_P ColLabel ')'
{
$$ = makeXmlExpr(IS_XMLELEMENT, $4,
NIL, NIL, @1);
--- 8620,8625 ----
*************** col_name_keyword:
*** 9672,9678 ****
| VALUES
| VARCHAR
| XMLATTRIBUTES
- | XMLCONCAT
| XMLELEMENT
| XMLFOREST
| XMLPARSE
--- 9668,9673 ----
Index: src/backend/parser/keywords.c
===================================================================
RCS file: /cvsroot/pgsql/src/backend/parser/keywords.c,v
retrieving revision 1.205
diff -u -3 -p -c -r1.205 keywords.c
*** src/backend/parser/keywords.c 27 Oct 2008 09:37:47 -0000 1.205
--- src/backend/parser/keywords.c 17 Nov 2008 11:17:09 -0000
*************** const ScanKeyword ScanKeywords[] = {
*** 414,420 ****
{"write", WRITE, UNRESERVED_KEYWORD},
{"xml", XML_P, UNRESERVED_KEYWORD},
{"xmlattributes", XMLATTRIBUTES, COL_NAME_KEYWORD},
- {"xmlconcat", XMLCONCAT, COL_NAME_KEYWORD},
{"xmlelement", XMLELEMENT, COL_NAME_KEYWORD},
{"xmlforest", XMLFOREST, COL_NAME_KEYWORD},
{"xmlparse", XMLPARSE, COL_NAME_KEYWORD},
--- 414,419 ----
Index: src/backend/parser/parse_expr.c
===================================================================
RCS file: /cvsroot/pgsql/src/backend/parser/parse_expr.c,v
retrieving revision 1.237
diff -u -3 -p -c -r1.237 parse_expr.c
*** src/backend/parser/parse_expr.c 26 Oct 2008 02:46:25 -0000 1.237
--- src/backend/parser/parse_expr.c 17 Nov 2008 11:17:09 -0000
*************** transformXmlExpr(ParseState *pstate, Xml
*** 1706,1715 ****
newe = transformExpr(pstate, e);
switch (x->op)
{
- case IS_XMLCONCAT:
- newe = coerce_to_specific_type(pstate, newe,
XMLOID,
-
"XMLCONCAT");
- break;
case IS_XMLELEMENT:
/* no coercion necessary */
break;
--- 1706,1711 ----
Index: src/backend/parser/parse_target.c
===================================================================
RCS file: /cvsroot/pgsql/src/backend/parser/parse_target.c,v
retrieving revision 1.168
diff -u -3 -p -c -r1.168 parse_target.c
*** src/backend/parser/parse_target.c 7 Oct 2008 01:47:55 -0000 1.168
--- src/backend/parser/parse_target.c 17 Nov 2008 11:17:09 -0000
*************** FigureColnameInternal(Node *node, char *
*** 1399,1407 ****
/* make SQL/XML functions act like a regular function */
switch (((XmlExpr *) node)->op)
{
- case IS_XMLCONCAT:
- *name = "xmlconcat";
- return 2;
case IS_XMLELEMENT:
*name = "xmlelement";
return 2;
--- 1399,1404 ----
Index: src/backend/utils/adt/ruleutils.c
===================================================================
RCS file: /cvsroot/pgsql/src/backend/utils/adt/ruleutils.c,v
retrieving revision 1.287
diff -u -3 -p -c -r1.287 ruleutils.c
*** src/backend/utils/adt/ruleutils.c 6 Oct 2008 20:29:38 -0000 1.287
--- src/backend/utils/adt/ruleutils.c 17 Nov 2008 11:17:09 -0000
*************** get_rule_expr(Node *node, deparse_contex
*** 4519,4527 ****
switch (xexpr->op)
{
- case IS_XMLCONCAT:
- appendStringInfoString(buf,
"XMLCONCAT(");
- break;
case IS_XMLELEMENT:
appendStringInfoString(buf,
"XMLELEMENT(");
break;
--- 4519,4524 ----
*************** get_rule_expr(Node *node, deparse_contex
*** 4586,4592 ****
appendStringInfoString(buf, ",
");
switch (xexpr->op)
{
- case IS_XMLCONCAT:
case IS_XMLELEMENT:
case IS_XMLFOREST:
case IS_XMLPI:
--- 4583,4588 ----
Index: src/backend/utils/adt/xml.c
===================================================================
RCS file: /cvsroot/pgsql/src/backend/utils/adt/xml.c,v
retrieving revision 1.81
diff -u -3 -p -c -r1.81 xml.c
*** src/backend/utils/adt/xml.c 10 Nov 2008 18:02:20 -0000 1.81
--- src/backend/utils/adt/xml.c 17 Nov 2008 11:17:10 -0000
*************** xmlcomment(PG_FUNCTION_ARGS)
*** 422,448 ****
* TODO: xmlconcat needs to merge the notations and unparsed entities
* of the argument values. Not very important in practice, though.
*/
! xmltype *
! xmlconcat(List *args)
{
#ifdef USE_LIBXML
int global_standalone = 1;
xmlChar *global_version = NULL;
bool global_version_no_value = false;
StringInfoData buf;
! ListCell *v;
initStringInfo(&buf);
! foreach(v, args)
{
- xmltype *x = DatumGetXmlP(PointerGetDatum(lfirst(v)));
size_t len;
xmlChar *version;
int standalone;
char *str;
! len = VARSIZE(x) - VARHDRSZ;
! str = text_to_cstring((text *) x);
parse_xml_decl((xmlChar *) str, &len, &version, NULL,
&standalone);
--- 422,449 ----
* TODO: xmlconcat needs to merge the notations and unparsed entities
* of the argument values. Not very important in practice, though.
*/
! static xmltype *
! xmlconcat_internal(int num, xmltype *args[])
{
#ifdef USE_LIBXML
int global_standalone = 1;
xmlChar *global_version = NULL;
bool global_version_no_value = false;
StringInfoData buf;
! int i;
!
! Assert(num > 0);
initStringInfo(&buf);
! for (i = 0; i < num; i++)
{
size_t len;
xmlChar *version;
int standalone;
char *str;
! len = VARSIZE(args[i]) - VARHDRSZ;
! str = text_to_cstring((text *) args[i]);
parse_xml_decl((xmlChar *) str, &len, &version, NULL,
&standalone);
*************** xmlconcat(List *args)
*** 485,490 ****
--- 486,524 ----
}
+ Datum
+ xmlconcatv(PG_FUNCTION_ARGS)
+ {
+ ArrayType *arg = PG_GETARG_ARRAYTYPE_P(0);
+ xmltype **newargs;
+ int num;
+ int i;
+
+ Assert(ARR_NDIM(arg) == 1);
+ Assert(ARR_ELEMTYPE(arg) == XMLOID);
+
+ newargs = palloc(sizeof(*newargs) * ARR_DIMS(arg)[0]);
+
+ num = 0;
+ for (i = ARR_LBOUND(arg)[0]; i < ARR_LBOUND(arg)[0] + ARR_DIMS(arg)[0];
i++)
+ {
+ Datum el;
+ bool isnull;
+
+ el = array_ref(arg, 1, &i, -1, -1, false, 'i', &isnull);
+ if (isnull)
+ continue;
+ else
+ newargs[num++] = DatumGetXmlP(el);
+ }
+
+ if (num > 0)
+ PG_RETURN_XML_P(xmlconcat_internal(num, newargs));
+ else
+ PG_RETURN_NULL();
+ }
+
+
/*
* XMLAGG support
*/
*************** xmlconcat2(PG_FUNCTION_ARGS)
*** 501,508 ****
else if (PG_ARGISNULL(1))
PG_RETURN_XML_P(PG_GETARG_XML_P(0));
else
! PG_RETURN_XML_P(xmlconcat(list_make2(PG_GETARG_XML_P(0),
!
PG_GETARG_XML_P(1))));
}
--- 535,547 ----
else if (PG_ARGISNULL(1))
PG_RETURN_XML_P(PG_GETARG_XML_P(0));
else
! {
! xmltype *newargs[2];
!
! newargs[0] = PG_GETARG_XML_P(0);
! newargs[1] = PG_GETARG_XML_P(1);
! PG_RETURN_XML_P(xmlconcat_internal(2, newargs));
! }
}
Index: src/include/catalog/pg_proc.h
===================================================================
RCS file: /cvsroot/pgsql/src/include/catalog/pg_proc.h,v
retrieving revision 1.528
diff -u -3 -p -c -r1.528 pg_proc.h
*** src/include/catalog/pg_proc.h 14 Nov 2008 00:51:46 -0000 1.528
--- src/include/catalog/pg_proc.h 17 Nov 2008 11:17:10 -0000
*************** DATA(insert OID = 2898 ( xml_recv P
*** 4193,4198 ****
--- 4193,4200 ----
DESCR("I/O");
DATA(insert OID = 2899 ( xml_send PGNSP PGUID 12 1 0 0 f f t f
s 1 17 "142" _null_ _null_ _null_ xml_send _null_ _null_ _null_ ));
DESCR("I/O");
+ DATA(insert OID = 2328 ( xmlconcat PGNSP PGUID 12 1 0 142 f f f
f i 1 142 "143" "{143}" "{v}" _null_ xmlconcatv _null_ _null_ _null_ ));
+ DESCR("concatenate a list of XML values");
DATA(insert OID = 2900 ( xmlconcat2 PGNSP PGUID 12 1 0 0 f f f f i 2 142
"142 142" _null_ _null_ _null_ xmlconcat2 _null_ _null_ _null_ ));
DESCR("aggregate transition function");
DATA(insert OID = 2901 ( xmlagg PGNSP PGUID 12 1 0 0 t f f f
i 1 142 "142" _null_ _null_ _null_ aggregate_dummy _null_ _null_ _null_ ));
Index: src/include/nodes/primnodes.h
===================================================================
RCS file: /cvsroot/pgsql/src/include/nodes/primnodes.h,v
retrieving revision 1.143
diff -u -3 -p -c -r1.143 primnodes.h
*** src/include/nodes/primnodes.h 6 Oct 2008 17:39:26 -0000 1.143
--- src/include/nodes/primnodes.h 17 Nov 2008 11:17:10 -0000
*************** typedef struct MinMaxExpr
*** 837,843 ****
*/
typedef enum XmlExprOp
{
- IS_XMLCONCAT, /* XMLCONCAT(args) */
IS_XMLELEMENT, /* XMLELEMENT(name,
xml_attributes, args) */
IS_XMLFOREST, /* XMLFOREST(xml_attributes) */
IS_XMLPARSE, /* XMLPARSE(text, is_doc,
preserve_ws) */
--- 837,842 ----
Index: src/include/utils/xml.h
===================================================================
RCS file: /cvsroot/pgsql/src/include/utils/xml.h,v
retrieving revision 1.24
diff -u -3 -p -c -r1.24 xml.h
*** src/include/utils/xml.h 4 Apr 2008 08:33:15 -0000 1.24
--- src/include/utils/xml.h 17 Nov 2008 11:17:10 -0000
*************** extern Datum xml_out(PG_FUNCTION_ARGS);
*** 32,37 ****
--- 32,38 ----
extern Datum xml_recv(PG_FUNCTION_ARGS);
extern Datum xml_send(PG_FUNCTION_ARGS);
extern Datum xmlcomment(PG_FUNCTION_ARGS);
+ extern Datum xmlconcatv(PG_FUNCTION_ARGS);
extern Datum xmlconcat2(PG_FUNCTION_ARGS);
extern Datum texttoxml(PG_FUNCTION_ARGS);
extern Datum xmltotext(PG_FUNCTION_ARGS);
*************** typedef enum
*** 63,69 ****
XML_STANDALONE_OMITTED
} XmlStandaloneType;
- extern xmltype *xmlconcat(List *args);
extern xmltype *xmlelement(XmlExprState *xmlExpr, ExprContext *econtext);
extern xmltype *xmlparse(text *data, XmlOptionType xmloption, bool
preserve_whitespace);
extern xmltype *xmlpi(char *target, text *arg, bool arg_is_null, bool
*result_is_null);
--- 64,69 ----
Index: src/test/regress/expected/xml.out
===================================================================
RCS file: /cvsroot/pgsql/src/test/regress/expected/xml.out,v
retrieving revision 1.23
diff -u -3 -p -c -r1.23 xml.out
*** src/test/regress/expected/xml.out 15 Nov 2008 20:52:35 -0000 1.23
--- src/test/regress/expected/xml.out 17 Nov 2008 11:17:10 -0000
*************** SELECT xmlconcat('hello', 'you');
*** 55,63 ****
(1 row)
SELECT xmlconcat(1, 2);
! ERROR: argument of XMLCONCAT must be type xml, not type integer
LINE 1: SELECT xmlconcat(1, 2);
! ^
SELECT xmlconcat('bad', '<syntax');
ERROR: invalid XML content
LINE 1: SELECT xmlconcat('bad', '<syntax');
--- 55,64 ----
(1 row)
SELECT xmlconcat(1, 2);
! ERROR: function xmlconcat(integer, integer) does not exist
LINE 1: SELECT xmlconcat(1, 2);
! ^
! HINT: No function matches the given name and argument types. You might need
to add explicit type casts.
SELECT xmlconcat('bad', '<syntax');
ERROR: invalid XML content
LINE 1: SELECT xmlconcat('bad', '<syntax');
*************** SELECT table_name, view_definition FROM
*** 435,441 ****
table_name |
view_definition
------------+----------------------------------------------------------------------------------------------------------------------------
xmlview1 | SELECT xmlcomment('test'::text) AS xmlcomment;
! xmlview2 | SELECT XMLCONCAT('hello'::xml, 'you'::xml) AS "xmlconcat";
xmlview3 | SELECT XMLELEMENT(NAME element, XMLATTRIBUTES(1 AS ":one:",
'deuce' AS two), 'content&') AS "xmlelement";
xmlview4 | SELECT XMLELEMENT(NAME employee, XMLFOREST(emp.name AS name,
emp.age AS age, emp.salary AS pay)) AS "xmlelement" FROM emp;
xmlview5 | SELECT XMLPARSE(CONTENT '<abc>x</abc>'::text STRIP WHITESPACE)
AS "xmlparse";
--- 436,442 ----
table_name |
view_definition
------------+----------------------------------------------------------------------------------------------------------------------------
xmlview1 | SELECT xmlcomment('test'::text) AS xmlcomment;
! xmlview2 | SELECT xmlconcat(VARIADIC ARRAY['hello'::xml, 'you'::xml]) AS
xmlconcat;
xmlview3 | SELECT XMLELEMENT(NAME element, XMLATTRIBUTES(1 AS ":one:",
'deuce' AS two), 'content&') AS "xmlelement";
xmlview4 | SELECT XMLELEMENT(NAME employee, XMLFOREST(emp.name AS name,
emp.age AS age, emp.salary AS pay)) AS "xmlelement" FROM emp;
xmlview5 | SELECT XMLPARSE(CONTENT '<abc>x</abc>'::text STRIP WHITESPACE)
AS "xmlparse";
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