Movatterモバイル変換

[0]ホーム
URL:

Skip to content

Navigation Menu

Sign in
Appearance settings

Search code, repositories, users, issues, pull requests...

Provide feedback

We read every piece of feedback, and take your input very seriously.

Saved searches

Use saved searches to filter your results more quickly

 Sign up
Appearance settings

Commit455dffb

Browse files
committed
Default values for function arguments
Pavel Stehule, with some tweaks by Peter Eisentraut
1 parent7b640b0 commit455dffb

File tree

29 files changed

+2848
-2166
lines changed

29 files changed

+2848
-2166
lines changed

‎doc/src/sgml/func.sgml

Lines changed: 17 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -1,4 +1,4 @@
1-
<!-- $PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.460 2008/11/14 00:51:46 tgl Exp $ -->
1+
<!-- $PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.461 2008/12/04 17:51:26 petere Exp $ -->
22

33
<chapter id="functions">
44
<title>Functions and Operators</title>
@@ -11710,6 +11710,10 @@ SELECT pg_type_is_visible('myschema.widget'::regtype);
1171011710
<primary>pg_get_function_arguments</primary>
1171111711
</indexterm>
1171211712

11713+
<indexterm>
11714+
<primary>pg_get_function_identity_arguments</primary>
11715+
</indexterm>
11716+
1171311717
<indexterm>
1171411718
<primary>pg_get_function_result</primary>
1171511719
</indexterm>
@@ -11799,7 +11803,12 @@ SELECT pg_type_is_visible('myschema.widget'::regtype);
1179911803
<row>
1180011804
<entry><literal><function>pg_get_function_arguments</function>(<parameter>func_oid</parameter>)</literal></entry>
1180111805
<entry><type>text</type></entry>
11802-
<entry>get argument list for function</entry>
11806+
<entry>get argument list of function's definition (with default values)</entry>
11807+
</row>
11808+
<row>
11809+
<entry><literal><function>pg_get_function_identity_arguments</function>(<parameter>func_oid</parameter>)</literal></entry>
11810+
<entry><type>text</type></entry>
11811+
<entry>get argument list to identify a function (without argument names, default values)</entry>
1180311812
</row>
1180411813
<row>
1180511814
<entry><literal><function>pg_get_function_result</function>(<parameter>func_oid</parameter>)</literal></entry>
@@ -11920,7 +11929,12 @@ SELECT pg_type_is_visible('myschema.widget'::regtype);
1192011929
of a function, in the form it would need to appear in within
1192111930
<command>CREATE FUNCTION</>.
1192211931
<function>pg_get_function_result</function> similarly returns the
11923-
appropriate <literal>RETURNS</> clause for the function.
11932+
appropriate <literal>RETURNS</> clause for the function.
11933+
<function>pg_get_function_identity_arguments</function> returns the
11934+
argument list necessary to identify a function, in the form it
11935+
would need to appear in within <command>ALTER FUNCTION</>, for
11936+
instance. This form omits default values and argument names, for
11937+
example.
1192411938
</para>
1192511939

1192611940
<para>

‎doc/src/sgml/ref/create_function.sgml

Lines changed: 24 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,5 @@
11
<!--
2-
$PostgreSQL: pgsql/doc/src/sgml/ref/create_function.sgml,v 1.81 2008/11/14 10:22:46 petere Exp $
2+
$PostgreSQL: pgsql/doc/src/sgml/ref/create_function.sgml,v 1.82 2008/12/04 17:51:26 petere Exp $
33
-->
44

55
<refentry id="SQL-CREATEFUNCTION">
@@ -21,7 +21,7 @@ $PostgreSQL: pgsql/doc/src/sgml/ref/create_function.sgml,v 1.81 2008/11/14 10:22
2121
<refsynopsisdiv>
2222
<synopsis>
2323
CREATE [ OR REPLACE ] FUNCTION
24-
<replaceable class="parameter">name</replaceable> ( [ [ <replaceable class="parameter">argmode</replaceable> ] [ <replaceable class="parameter">argname</replaceable> ] <replaceable class="parameter">argtype</replaceable> [, ...] ] )
24+
<replaceable class="parameter">name</replaceable> ( [ [ <replaceable class="parameter">argmode</replaceable> ] [ <replaceable class="parameter">argname</replaceable> ] <replaceable class="parameter">argtype</replaceable> [ { DEFAULT | = } <replaceable class="parameter">defexpr</replaceable>] [, ...] ] )
2525
[ RETURNS <replaceable class="parameter">rettype</replaceable>
2626
| RETURNS TABLE ( <replaceable class="parameter">colname</replaceable> <replaceable class="parameter">coltype</replaceable> [, ...] ) ]
2727
{ LANGUAGE <replaceable class="parameter">langname</replaceable>
@@ -154,6 +154,20 @@ CREATE [ OR REPLACE ] FUNCTION
154154
</listitem>
155155
</varlistentry>
156156

157+
<varlistentry>
158+
<term><replaceable class="parameter">defexpr</replaceable></term>
159+
160+
<listitem>
161+
<para>
162+
An expression to be used as default value if the parameter is
163+
not specified. The expression has to be convertable to the
164+
argument type of the parameter. All parameters after a
165+
parameter with default value have to be parameters with default
166+
values as well.
167+
</para>
168+
</listitem>
169+
</varlistentry>
170+
157171
<varlistentry>
158172
<term><replaceable class="parameter">rettype</replaceable></term>
159173

@@ -667,6 +681,14 @@ COMMIT;
667681
either before or after <replaceable class="parameter">argname</replaceable>.
668682
But only the first way is standard-compliant.
669683
</para>
684+
685+
<para>
686+
The SQL standard does not specify parameter defaults. The syntax
687+
with the <literal>DEFAULT</literal> key word is from Oracle, and it
688+
is somewhat in the spirit of the standard: SQL/PSM uses it for
689+
variable default values. The syntax with <literal>=</literal> is
690+
used in T-SQL and Firebird.
691+
</para>
670692
</refsect1>
671693

672694

‎doc/src/sgml/xfunc.sgml

Lines changed: 55 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1,4 +1,4 @@
1-
<!-- $PostgreSQL: pgsql/doc/src/sgml/xfunc.sgml,v 1.133 2008/10/31 19:37:56 tgl Exp $ -->
1+
<!-- $PostgreSQL: pgsql/doc/src/sgml/xfunc.sgml,v 1.134 2008/12/04 17:51:26 petere Exp $ -->
22

33
<sect1 id="xfunc">
44
<title>User-Defined Functions</title>
@@ -663,6 +663,60 @@ SELECT mleast(VARIADIC ARRAY[10, -1, 5, 4.4]);
663663
</para>
664664
</sect2>
665665

666+
<sect2 id="xfunc-parameter-defaults">
667+
<title><acronym>SQL</> Functions with Parameters Default Values</title>
668+
669+
<indexterm>
670+
<primary>default values</primary>
671+
</indexterm>
672+
673+
<para>
674+
Functions can be declared with parameters with default values or
675+
expressions. The default expressions are used as parameter value
676+
if the parameter is not explicitly specified in a function call.
677+
All parameters after a a parameter with default value have to be
678+
parameters with default values as well.
679+
</para>
680+
681+
<para>
682+
For example:
683+
<screen>
684+
CREATE FUNCTION foo(a int DEFAULT 1, b int DEFAULT 2, c int DEFAULT 3)
685+
RETURNS int
686+
LANGUAGE SQL
687+
AS $$
688+
SELECT $1 + $2 + $3;
689+
$$;
690+
691+
SELECT foo(10, 20, 30);
692+
foo
693+
-----
694+
60
695+
(1 row)
696+
697+
SELECT foo(10, 20);
698+
foo
699+
-----
700+
33
701+
(1 row)
702+
703+
SELECT foo(10);
704+
foo
705+
-----
706+
15
707+
(1 row)
708+
709+
SELECT foo();
710+
foo
711+
-----
712+
6
713+
(1 row)
714+
</screen>
715+
Instead of the key word <literal>DEFAULT</literal>,
716+
the <literal>=</literal> sign can also be used.
717+
</para>
718+
</sect2>
719+
666720
<sect2 id="xfunc-sql-table-functions">
667721
<title><acronym>SQL</acronym> Functions as Table Sources</title>
668722

‎src/backend/catalog/namespace.c

Lines changed: 80 additions & 7 deletions
Original file line numberDiff line numberDiff line change
@@ -13,7 +13,7 @@
1313
* Portions Copyright (c) 1994, Regents of the University of California
1414
*
1515
* IDENTIFICATION
16-
* $PostgreSQL: pgsql/src/backend/catalog/namespace.c,v 1.112 2008/09/09 18:58:08 tgl Exp $
16+
* $PostgreSQL: pgsql/src/backend/catalog/namespace.c,v 1.113 2008/12/04 17:51:26 petere Exp $
1717
*
1818
*-------------------------------------------------------------------------
1919
*/
@@ -571,6 +571,11 @@ TypeIsVisible(Oid typid)
571571
* If expand_variadic is false, variadic arguments are not treated specially,
572572
* and the returned nvargs will always be zero.
573573
*
574+
* If expand_variadic is true, functions with argument default values
575+
* will also be retrieved. If expand_variadic is false, default
576+
* values will not be taken into account and functions that do not
577+
* have exactly nargs arguments in total will not be considered.
578+
*
574579
* We search a single namespace if the function name is qualified, else
575580
* all namespaces in the search path. The return list will never contain
576581
* multiple entries with identical argument lists --- in the multiple-
@@ -621,13 +626,45 @@ FuncnameGetCandidates(List *names, int nargs, bool expand_variadic)
621626
intpathpos=0;
622627
boolvariadic;
623628
Oidva_elem_type;
629+
List*defaults=NIL;
624630
FuncCandidateListnewResult;
625631

632+
/*
633+
* Check if function has some parameter defaults if some
634+
* parameters are missing.
635+
*/
636+
if (pronargs>nargs&&expand_variadic)
637+
{
638+
boolisnull;
639+
Datumproargdefaults;
640+
char*str;
641+
642+
/* skip when not enough default expressions */
643+
if (nargs+procform->pronargdefaults<pronargs)
644+
continue;
645+
646+
proargdefaults=SysCacheGetAttr(PROCOID,proctup,
647+
Anum_pg_proc_proargdefaults,&isnull);
648+
Assert(!isnull);
649+
str=TextDatumGetCString(proargdefaults);
650+
defaults= (List*)stringToNode(str);
651+
652+
Assert(IsA(defaults,List));
653+
654+
/*
655+
* If we don't have to use all default parameters, we skip
656+
* some cells from the left.
657+
*/
658+
defaults=list_copy_tail(defaults,procform->pronargdefaults-pronargs+nargs);
659+
660+
pfree(str);
661+
}
662+
626663
/*
627664
* Check if function is variadic, and get variadic element type if so.
628665
* If expand_variadic is false, we should just ignore variadic-ness.
629666
*/
630-
if (expand_variadic)
667+
if (pronargs <=nargs&&expand_variadic)
631668
{
632669
va_elem_type=procform->provariadic;
633670
variadic=OidIsValid(va_elem_type);
@@ -638,11 +675,16 @@ FuncnameGetCandidates(List *names, int nargs, bool expand_variadic)
638675
variadic= false;
639676
}
640677

678+
Assert(!variadic|| !defaults);
679+
641680
/* Ignore if it doesn't match requested argument count */
642681
if (nargs >=0&&
643-
(variadic ? (pronargs>nargs) : (pronargs!=nargs)))
682+
(variadic ? (pronargs>nargs) : (defaults ? (pronargs<nargs) : (pronargs!=nargs))))
644683
continue;
645684

685+
Assert(!variadic|| (pronargs <=nargs));
686+
Assert(!defaults|| (pronargs>nargs));
687+
646688
if (OidIsValid(namespaceId))
647689
{
648690
/* Consider only procs in specified namespace */
@@ -681,6 +723,7 @@ FuncnameGetCandidates(List *names, int nargs, bool expand_variadic)
681723
newResult->pathpos=pathpos;
682724
newResult->oid=HeapTupleGetOid(proctup);
683725
newResult->nargs=effective_nargs;
726+
newResult->argdefaults=defaults;
684727
memcpy(newResult->args,procform->proargtypes.values,
685728
pronargs*sizeof(Oid));
686729
if (variadic)
@@ -695,6 +738,8 @@ FuncnameGetCandidates(List *names, int nargs, bool expand_variadic)
695738
else
696739
newResult->nvargs=0;
697740

741+
any_variadic=variadic||defaults;
742+
698743
/*
699744
* Does it have the same arguments as something we already accepted?
700745
* If so, decide which one to keep. We can skip this check for the
@@ -704,6 +749,9 @@ FuncnameGetCandidates(List *names, int nargs, bool expand_variadic)
704749
*/
705750
if (any_variadic|| !OidIsValid(namespaceId))
706751
{
752+
if (defaults)
753+
effective_nargs=nargs;
754+
707755
/*
708756
* If we have an ordered list from SearchSysCacheList (the normal
709757
* case), then any conflicting proc must immediately adjoin this
@@ -733,11 +781,21 @@ FuncnameGetCandidates(List *names, int nargs, bool expand_variadic)
733781
prevResult;
734782
prevResult=prevResult->next)
735783
{
736-
if (effective_nargs==prevResult->nargs&&
737-
memcmp(newResult->args,
738-
prevResult->args,
739-
effective_nargs*sizeof(Oid))==0)
784+
if (!defaults)
785+
{
786+
if (effective_nargs==prevResult->nargs&&
787+
memcmp(newResult->args,
788+
prevResult->args,
789+
effective_nargs*sizeof(Oid))==0)
790+
break;
791+
}
792+
else
793+
{
794+
if (memcmp(newResult->args,
795+
prevResult->args,
796+
effective_nargs*sizeof(Oid))==0)
740797
break;
798+
}
741799
}
742800
}
743801
if (prevResult)
@@ -777,13 +835,28 @@ FuncnameGetCandidates(List *names, int nargs, bool expand_variadic)
777835
pfree(newResult);
778836
continue;/* keep previous result */
779837
}
838+
839+
if (defaults)
840+
{
841+
if (prevResult->argdefaults!=NIL)
842+
ereport(ERROR,
843+
(errcode(ERRCODE_AMBIGUOUS_FUNCTION),
844+
errmsg("functions with parameter defaults %s and %s are ambiguous",
845+
func_signature_string(names,pronargs,procform->proargtypes.values),
846+
func_signature_string(names,prevResult->nargs,prevResult->args))));
847+
/* else, previous result didn't have defaults */
848+
pfree(newResult);
849+
continue;/* keep previous result */
850+
}
851+
780852
/* non-variadic can replace a previous variadic */
781853
Assert(prevResult->nvargs>0);
782854
}
783855
/* replace previous result */
784856
prevResult->pathpos=pathpos;
785857
prevResult->oid=newResult->oid;
786858
prevResult->nvargs=newResult->nvargs;
859+
prevResult->argdefaults=newResult->argdefaults;
787860
pfree(newResult);
788861
continue;/* args are same, of course */
789862
}

‎src/backend/catalog/pg_aggregate.c

Lines changed: 4 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $PostgreSQL: pgsql/src/backend/catalog/pg_aggregate.c,v 1.97 2008/11/14 19:47:50 tgl Exp $
11+
* $PostgreSQL: pgsql/src/backend/catalog/pg_aggregate.c,v 1.98 2008/12/04 17:51:26 petere Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -229,7 +229,8 @@ AggregateCreate(const char *aggName,
229229
PointerGetDatum(NULL),/* parameterNames */
230230
PointerGetDatum(NULL),/* proconfig */
231231
1,/* procost */
232-
0);/* prorows */
232+
0,/* prorows */
233+
NULL);/* parameterDefaults */
233234

234235
/*
235236
* Okay to create the pg_aggregate entry.
@@ -321,7 +322,7 @@ lookup_agg_function(List *fnName,
321322
*/
322323
fdresult=func_get_detail(fnName,NIL,nargs,input_types, false,
323324
&fnOid,rettype,&retset,&nvargs,
324-
&true_oid_array);
325+
&true_oid_array,NULL);
325326

326327
/* only valid case is a normal function not returning a set */
327328
if (fdresult!=FUNCDETAIL_NORMAL|| !OidIsValid(fnOid))

0 commit comments

Comments
 (0)
[8]ページ先頭
©2009-2025 Movatter.jp