Default values for function arguments

Pavel Stehule, with some tweaks by Peter Eisentraut

doc/src/sgml/func.sgml

-<!-- $PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.460 2008/11/14 00:51:46 tgl Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.461 2008/12/04 17:51:26 petere Exp $ -->
 
  <chapter id="functions">
   <title>Functions and Operators</title>
@@ -11710,6 +11710,10 @@ SELECT pg_type_is_visible('myschema.widget'::regtype);
     <primary>pg_get_function_arguments</primary>
    </indexterm>
 
+   <indexterm>
+    <primary>pg_get_function_identity_arguments</primary>
+   </indexterm>
+
    <indexterm>
     <primary>pg_get_function_result</primary>
    </indexterm>
@@ -11799,7 +11803,12 @@ SELECT pg_type_is_visible('myschema.widget'::regtype);
       <row>
        <entry><literal><function>pg_get_function_arguments</function>(<parameter>func_oid</parameter>)</literal></entry>
        <entry><type>text</type></entry>
-       <entry>get argument list for function</entry>
+       <entry>get argument list of function's definition (with default values)</entry>
+      </row>
+      <row>
+       <entry><literal><function>pg_get_function_identity_arguments</function>(<parameter>func_oid</parameter>)</literal></entry>
+       <entry><type>text</type></entry>
+       <entry>get argument list to identify a function (without argument names, default values)</entry>
       </row>
       <row>
        <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);
    of a function, in the form it would need to appear in within
    <command>CREATE FUNCTION</>.
    <function>pg_get_function_result</function> similarly returns the
-   appropriate <literal>RETURNS</> clause for the function.
+   appropriate <literal>RETURNS</> clause for the function. 
+   <function>pg_get_function_identity_arguments</function> returns the
+   argument list necessary to identify a function, in the form it
+   would need to appear in within <command>ALTER FUNCTION</>, for
+   instance.  This form omits default values and argument names, for
+   example.
   </para>
 
   <para>

doc/src/sgml/ref/create_function.sgml

 <!--
-$PostgreSQL: pgsql/doc/src/sgml/ref/create_function.sgml,v 1.81 2008/11/14 10:22:46 petere Exp $
+$PostgreSQL: pgsql/doc/src/sgml/ref/create_function.sgml,v 1.82 2008/12/04 17:51:26 petere Exp $
 -->
 
 <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
  <refsynopsisdiv>
 <synopsis>
 CREATE [ OR REPLACE ] FUNCTION
-    <replaceable class="parameter">name</replaceable> ( [ [ <replaceable class="parameter">argmode</replaceable> ] [ <replaceable class="parameter">argname</replaceable> ] <replaceable class="parameter">argtype</replaceable> [, ...] ] )
+    <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>] [, ...] ] )
     [ RETURNS <replaceable class="parameter">rettype</replaceable>
       | RETURNS TABLE ( <replaceable class="parameter">colname</replaceable> <replaceable class="parameter">coltype</replaceable> [, ...] ) ]
   { LANGUAGE <replaceable class="parameter">langname</replaceable>
@@ -154,6 +154,20 @@ CREATE [ OR REPLACE ] FUNCTION
      </listitem>
     </varlistentry>
 
+    <varlistentry>
+     <term><replaceable class="parameter">defexpr</replaceable></term>
+
+     <listitem>
+      <para>
+       An expression to be used as default value if the parameter is
+       not specified.  The expression has to be convertable to the
+       argument type of the parameter.  All parameters after a
+       parameter with default value have to be parameters with default
+       values as well.
+      </para>
+     </listitem>
+    </varlistentry>
+
     <varlistentry>
      <term><replaceable class="parameter">rettype</replaceable></term>
 
@@ -667,6 +681,14 @@ COMMIT;
    either before or after <replaceable class="parameter">argname</replaceable>.
    But only the first way is standard-compliant.
   </para>
+
+  <para>
+   The SQL standard does not specify parameter defaults.  The syntax
+   with the <literal>DEFAULT</literal> key word is from Oracle, and it
+   is somewhat in the spirit of the standard: SQL/PSM uses it for
+   variable default values.  The syntax with <literal>=</literal> is
+   used in T-SQL and Firebird.
+  </para>
  </refsect1>
 
 

doc/src/sgml/xfunc.sgml

-<!-- $PostgreSQL: pgsql/doc/src/sgml/xfunc.sgml,v 1.133 2008/10/31 19:37:56 tgl Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/xfunc.sgml,v 1.134 2008/12/04 17:51:26 petere Exp $ -->
 
  <sect1 id="xfunc">
   <title>User-Defined Functions</title>
@@ -663,6 +663,60 @@ SELECT mleast(VARIADIC ARRAY[10, -1, 5, 4.4]);
     </para>
    </sect2>
 
+   <sect2 id="xfunc-parameter-defaults">
+    <title><acronym>SQL</> Functions with Parameters Default Values</title>
+
+    <indexterm>
+     <primary>default values</primary>
+    </indexterm>
+
+    <para>
+     Functions can be declared with parameters with default values or
+     expressions.  The default expressions are used as parameter value
+     if the parameter is not explicitly specified in a function call.
+     All parameters after a a parameter with default value have to be
+     parameters with default values as well.
+    </para>
+
+    <para>
+     For example:
+<screen>
+CREATE FUNCTION foo(a int DEFAULT 1, b int DEFAULT 2, c int DEFAULT 3) 
+RETURNS int
+LANGUAGE SQL
+AS $$
+    SELECT $1 + $2 + $3;
+$$;
+
+SELECT foo(10, 20, 30);
+ foo 
+-----
+  60
+(1 row)
+
+SELECT foo(10, 20);
+ foo 
+-----
+  33
+(1 row)
+
+SELECT foo(10);
+ foo 
+-----
+  15
+(1 row)
+
+SELECT foo();
+ foo 
+-----
+   6
+(1 row)
+</screen>
+     Instead of the key word <literal>DEFAULT</literal>,
+     the <literal>=</literal> sign can also be used.
+    </para>
+   </sect2>
+
    <sect2 id="xfunc-sql-table-functions">
     <title><acronym>SQL</acronym> Functions as Table Sources</title>
 

src/backend/catalog/namespace.c

@@ -13,7 +13,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/catalog/namespace.c,v 1.112 2008/09/09 18:58:08 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/catalog/namespace.c,v 1.113 2008/12/04 17:51:26 petere Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -571,6 +571,11 @@ TypeIsVisible(Oid typid)
  * If expand_variadic is false, variadic arguments are not treated specially,
  * and the returned nvargs will always be zero.
  *
+ * If expand_variadic is true, functions with argument default values
+ * will also be retrieved.  If expand_variadic is false, default
+ * values will not be taken into account and functions that do not
+ * have exactly nargs arguments in total will not be considered.
+ *
  * We search a single namespace if the function name is qualified, else
  * all namespaces in the search path.  The return list will never contain
  * multiple entries with identical argument lists --- in the multiple-
@@ -621,13 +626,45 @@ FuncnameGetCandidates(List *names, int nargs, bool expand_variadic)
 		int			pathpos = 0;
 		bool		variadic;
 		Oid			va_elem_type;
+		List	   *defaults = NIL;
 		FuncCandidateList newResult;
 
+		/*
+		 * Check if function has some parameter defaults if some
+		 * parameters are missing.
+		 */
+		if (pronargs > nargs && expand_variadic)
+		{
+			bool		isnull;
+			Datum		proargdefaults;
+			char	   *str;
+
+			/* skip when not enough default expressions */
+			if (nargs + procform->pronargdefaults < pronargs)
+				continue;
+
+			proargdefaults = SysCacheGetAttr(PROCOID, proctup,
+											 Anum_pg_proc_proargdefaults, &isnull);
+			Assert(!isnull);
+			str = TextDatumGetCString(proargdefaults);
+			defaults = (List *) stringToNode(str);
+
+			Assert(IsA(defaults, List));
+
+			/*
+			 * If we don't have to use all default parameters, we skip
+			 * some cells from the left.
+			 */
+			defaults = list_copy_tail(defaults, procform->pronargdefaults - pronargs + nargs);
+
+			pfree(str);
+		}
+
 		/*
 		 * Check if function is variadic, and get variadic element type if so.
 		 * If expand_variadic is false, we should just ignore variadic-ness.
 		 */
-		if (expand_variadic)
+		if (pronargs <= nargs && expand_variadic)
 		{
 			va_elem_type = procform->provariadic;
 			variadic = OidIsValid(va_elem_type);
@@ -638,11 +675,16 @@ FuncnameGetCandidates(List *names, int nargs, bool expand_variadic)
 			variadic = false;
 		}
 
+		Assert(!variadic || !defaults);
+
 		/* Ignore if it doesn't match requested argument count */
 		if (nargs >= 0 &&
-			(variadic ? (pronargs > nargs) : (pronargs != nargs)))
+			(variadic ? (pronargs > nargs) : (defaults ? (pronargs < nargs) : (pronargs != nargs))))
 			continue;
 
+		Assert(!variadic || (pronargs <= nargs));
+		Assert(!defaults || (pronargs > nargs));
+
 		if (OidIsValid(namespaceId))
 		{
 			/* Consider only procs in specified namespace */
@@ -681,6 +723,7 @@ FuncnameGetCandidates(List *names, int nargs, bool expand_variadic)
 		newResult->pathpos = pathpos;
 		newResult->oid = HeapTupleGetOid(proctup);
 		newResult->nargs = effective_nargs;
+		newResult->argdefaults = defaults;
 		memcpy(newResult->args, procform->proargtypes.values,
 			   pronargs * sizeof(Oid));
 		if (variadic)
@@ -695,6 +738,8 @@ FuncnameGetCandidates(List *names, int nargs, bool expand_variadic)
 		else
 			newResult->nvargs = 0;
 
+		any_variadic = variadic || defaults;
+
 		/*
 		 * Does it have the same arguments as something we already accepted?
 		 * 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)
 		 */
 		if (any_variadic || !OidIsValid(namespaceId))
 		{
+			if (defaults)
+				effective_nargs = nargs;
+
 			/*
 			 * If we have an ordered list from SearchSysCacheList (the normal
 			 * case), then any conflicting proc must immediately adjoin this
@@ -733,11 +781,21 @@ FuncnameGetCandidates(List *names, int nargs, bool expand_variadic)
 						 prevResult;
 						 prevResult = prevResult->next)
 					{
-						if (effective_nargs == prevResult->nargs &&
-							memcmp(newResult->args,
-								   prevResult->args,
-								   effective_nargs * sizeof(Oid)) == 0)
+						if (!defaults)
+						{
+							if (effective_nargs == prevResult->nargs &&
+								memcmp(newResult->args,
+									    prevResult->args,
+									    effective_nargs * sizeof(Oid)) == 0)
+								break;
+						}
+						else
+						{
+							if (memcmp(newResult->args,
+									    prevResult->args,
+									    effective_nargs * sizeof(Oid)) == 0)
 							break;
+						}
 					}
 				}
 				if (prevResult)
@@ -777,6 +835,20 @@ FuncnameGetCandidates(List *names, int nargs, bool expand_variadic)
 							pfree(newResult);
 							continue;	/* keep previous result */
 						}
+
+						if (defaults)
+						{
+							if (prevResult->argdefaults != NIL)
+								ereport(ERROR,
+										(errcode(ERRCODE_AMBIGUOUS_FUNCTION),
+										 errmsg("functions with parameter defaults %s and %s are ambiguous",
+												func_signature_string(names, pronargs, procform->proargtypes.values),
+												func_signature_string(names, prevResult->nargs, prevResult->args))));
+							/* else, previous result didn't have defaults */
+							pfree(newResult);
+							continue;	/* keep previous result */
+						}
+
 						/* non-variadic can replace a previous variadic */
 						Assert(prevResult->nvargs > 0);
 					}
@@ -784,6 +856,7 @@ FuncnameGetCandidates(List *names, int nargs, bool expand_variadic)
 					prevResult->pathpos = pathpos;
 					prevResult->oid = newResult->oid;
 					prevResult->nvargs = newResult->nvargs;
+					prevResult->argdefaults = newResult->argdefaults;
 					pfree(newResult);
 					continue;	/* args are same, of course */
 				}

src/backend/catalog/pg_aggregate.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/catalog/pg_aggregate.c,v 1.97 2008/11/14 19:47:50 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/catalog/pg_aggregate.c,v 1.98 2008/12/04 17:51:26 petere Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -229,7 +229,8 @@ AggregateCreate(const char *aggName,
 							  PointerGetDatum(NULL),	/* parameterNames */
 							  PointerGetDatum(NULL),	/* proconfig */
 							  1,	/* procost */
-							  0);		/* prorows */
+							  0,		/* prorows */
+							  NULL);	/* parameterDefaults */
 
 	/*
 	 * Okay to create the pg_aggregate entry.
@@ -321,7 +322,7 @@ lookup_agg_function(List *fnName,
 	 */
 	fdresult = func_get_detail(fnName, NIL, nargs, input_types, false,
 							   &fnOid, rettype, &retset, &nvargs,
-							   &true_oid_array);
+							   &true_oid_array, NULL);
 
 	/* only valid case is a normal function not returning a set */
 	if (fdresult != FUNCDETAIL_NORMAL || !OidIsValid(fnOid))

src/backend/catalog/pg_proc.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/catalog/pg_proc.c,v 1.154 2008/11/02 01:45:27 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/catalog/pg_proc.c,v 1.155 2008/12/04 17:51:26 petere Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -75,7 +75,8 @@ ProcedureCreate(const char *procedureName,
 				Datum parameterNames,
 				Datum proconfig,
 				float4 procost,
-				float4 prorows)
+				float4 prorows,
+				List *parameterDefaults)
 {
 	Oid			retval;
 	int			parameterCount;
@@ -295,6 +296,7 @@ ProcedureCreate(const char *procedureName,
 	values[Anum_pg_proc_proretset - 1] = BoolGetDatum(returnsSet);
 	values[Anum_pg_proc_provolatile - 1] = CharGetDatum(volatility);
 	values[Anum_pg_proc_pronargs - 1] = UInt16GetDatum(parameterCount);
+	values[Anum_pg_proc_pronargdefaults - 1] = UInt16GetDatum(list_length(parameterDefaults));
 	values[Anum_pg_proc_prorettype - 1] = ObjectIdGetDatum(returnType);
 	values[Anum_pg_proc_proargtypes - 1] = PointerGetDatum(parameterTypes);
 	if (allParameterTypes != PointerGetDatum(NULL))
@@ -309,6 +311,13 @@ ProcedureCreate(const char *procedureName,
 		values[Anum_pg_proc_proargnames - 1] = parameterNames;
 	else
 		nulls[Anum_pg_proc_proargnames - 1] = true;
+	if (parameterDefaults != PointerGetDatum(NULL))
+	{
+		Assert(list_length(parameterDefaults) > 0);
+		values[Anum_pg_proc_proargdefaults - 1] = CStringGetTextDatum(nodeToString(parameterDefaults));
+	}
+	else
+		nulls[Anum_pg_proc_proargdefaults - 1] = true;
 	values[Anum_pg_proc_prosrc - 1] = CStringGetTextDatum(prosrc);
 	if (probin)
 		values[Anum_pg_proc_probin - 1] = CStringGetTextDatum(probin);

src/backend/commands/functioncmds.c

@@ -10,7 +10,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/functioncmds.c,v 1.101 2008/11/02 01:45:27 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/functioncmds.c,v 1.102 2008/12/04 17:51:26 petere Exp $
  *
  * DESCRIPTION
  *	  These routines take the parse tree and pick out the
@@ -49,8 +49,10 @@
 #include "commands/proclang.h"
 #include "miscadmin.h"
 #include "parser/parse_coerce.h"
+#include "parser/parse_expr.h"
 #include "parser/parse_func.h"
 #include "parser/parse_type.h"
+#include "parser/parse_utilcmd.h"
 #include "utils/acl.h"
 #include "utils/builtins.h"
 #include "utils/fmgroids.h"
@@ -164,7 +166,9 @@ examine_parameter_list(List *parameters, Oid languageOid,
 					   ArrayType **allParameterTypes,
 					   ArrayType **parameterModes,
 					   ArrayType **parameterNames,
-					   Oid *requiredResultType)
+					   List **parameterDefaults,
+					   Oid *requiredResultType,
+					   const char *queryString)
 {
 	int			parameterCount = list_length(parameters);
 	Oid		   *inTypes;
@@ -177,6 +181,8 @@ examine_parameter_list(List *parameters, Oid languageOid,
 	bool		have_names = false;
 	ListCell   *x;
 	int			i;
+	bool		have_defaults = false;
+	ParseState *pstate;
 
 	*requiredResultType = InvalidOid;	/* default result */
 
@@ -184,6 +190,10 @@ examine_parameter_list(List *parameters, Oid languageOid,
 	allTypes = (Datum *) palloc(parameterCount * sizeof(Datum));
 	paramModes = (Datum *) palloc(parameterCount * sizeof(Datum));
 	paramNames = (Datum *) palloc0(parameterCount * sizeof(Datum));
+	*parameterDefaults = NIL;
+
+	pstate = make_parsestate(NULL);
+	pstate->p_sourcetext = queryString;
 
 	/* Scan the list and extract data into work arrays */
 	i = 0;
@@ -276,9 +286,33 @@ examine_parameter_list(List *parameters, Oid languageOid,
 			have_names = true;
 		}
 
+		if (fp->defexpr)
+		{
+			if (fp->mode != FUNC_PARAM_IN && fp->mode != FUNC_PARAM_INOUT)
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
+						 errmsg("only IN and INOUT parameters can have default values")));
+
+			*parameterDefaults = lappend(*parameterDefaults,
+										 coerce_to_specific_type(NULL,
+																 transformExpr(pstate, fp->defexpr),
+																 toid,
+																 "DEFAULT"));
+			have_defaults = true;
+		}
+		else
+		{
+			if (have_defaults)
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
+						 errmsg("parameter without default value specified after parameter with default value")));
+		}
+
 		i++;
 	}
 
+	free_parsestate(pstate);
+
 	/* Now construct the proper outputs as needed */
 	*parameterTypes = buildoidvector(inTypes, inCount);
 
@@ -653,7 +687,7 @@ interpret_AS_clause(Oid languageOid, const char *languageName,
  *	 Execute a CREATE FUNCTION utility statement.
  */
 void
-CreateFunction(CreateFunctionStmt *stmt)
+CreateFunction(CreateFunctionStmt *stmt, const char *queryString)
 {
 	char	   *probin_str;
 	char	   *prosrc_str;
@@ -680,6 +714,7 @@ CreateFunction(CreateFunctionStmt *stmt)
 	HeapTuple	languageTuple;
 	Form_pg_language languageStruct;
 	List	   *as_clause;
+	List		*defaults = NULL;
 
 	/* Convert list of names to a name and namespace */
 	namespaceId = QualifiedNameGetCreationNamespace(stmt->funcname,
@@ -753,7 +788,9 @@ CreateFunction(CreateFunctionStmt *stmt)
 						   &allParameterTypes,
 						   &parameterModes,
 						   &parameterNames,
-						   &requiredResultType);
+						   &defaults,
+						   &requiredResultType,
+						   queryString);
 
 	if (stmt->returnType)
 	{
@@ -836,7 +873,8 @@ CreateFunction(CreateFunctionStmt *stmt)
 					PointerGetDatum(parameterNames),
 					PointerGetDatum(proconfig),
 					procost,
-					prorows);
+					prorows,
+					defaults);
 }
 
 

src/backend/commands/proclang.c

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/proclang.c,v 1.80 2008/11/02 01:45:27 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/proclang.c,v 1.81 2008/12/04 17:51:26 petere Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -149,7 +149,8 @@ CreateProceduralLanguage(CreatePLangStmt *stmt)
 										 PointerGetDatum(NULL),
 										 PointerGetDatum(NULL),
 										 1,
-										 0);
+										 0,
+										 NULL);
 		}
 
 		/*
@@ -182,7 +183,8 @@ CreateProceduralLanguage(CreatePLangStmt *stmt)
 										 PointerGetDatum(NULL),
 										 PointerGetDatum(NULL),
 										 1,
-										 0);
+										 0,
+										 NULL);
 			}
 		}
 		else

src/backend/nodes/copyfuncs.c

@@ -15,7 +15,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/nodes/copyfuncs.c,v 1.414 2008/12/04 11:42:23 heikki Exp $
+ *	  $PostgreSQL: pgsql/src/backend/nodes/copyfuncs.c,v 1.415 2008/12/04 17:51:26 petere Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -2448,6 +2448,7 @@ _copyFunctionParameter(FunctionParameter *from)
 	COPY_STRING_FIELD(name);
 	COPY_NODE_FIELD(argType);
 	COPY_SCALAR_FIELD(mode);
+	COPY_NODE_FIELD(defexpr);
 
 	return newnode;
 }

src/backend/nodes/equalfuncs.c

@@ -22,7 +22,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/nodes/equalfuncs.c,v 1.339 2008/12/04 11:42:24 heikki Exp $
+ *	  $PostgreSQL: pgsql/src/backend/nodes/equalfuncs.c,v 1.340 2008/12/04 17:51:26 petere Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1165,6 +1165,7 @@ _equalFunctionParameter(FunctionParameter *a, FunctionParameter *b)
 	COMPARE_STRING_FIELD(name);
 	COMPARE_NODE_FIELD(argType);
 	COMPARE_SCALAR_FIELD(mode);
+	COMPARE_NODE_FIELD(defexpr);
 
 	return true;
 }

src/backend/parser/gram.y

@@ -11,7 +11,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/parser/gram.y,v 2.642 2008/12/04 11:42:24 heikki Exp $
+ *	  $PostgreSQL: pgsql/src/backend/parser/gram.y,v 2.643 2008/12/04 17:51:26 petere Exp $
  *
  * HISTORY
  *	  AUTHOR			DATE			MAJOR EVENT
@@ -255,6 +255,7 @@ static TypeName *TableFuncTypeName(List *columns);
 %type <list>	stmtblock stmtmulti
 				OptTableElementList TableElementList OptInherit definition
 				OptWith opt_distinct opt_definition func_args func_args_list
+				func_args_with_defaults func_args_with_defaults_list
 				func_as createfunc_opt_list alterfunc_opt_list
 				aggr_args old_aggr_definition old_aggr_list
 				oper_argtypes RuleActionList RuleActionMulti
@@ -278,7 +279,7 @@ static TypeName *TableFuncTypeName(List *columns);
 %type <into>	into_clause create_as_target
 
 %type <defelt>	createfunc_opt_item common_func_opt_item
-%type <fun_param> func_arg table_func_column
+%type <fun_param> func_arg func_arg_with_default table_func_column
 %type <fun_param_mode> arg_class
 %type <typnam>	func_return func_type
 
@@ -4170,7 +4171,7 @@ opt_nulls_order: NULLS_FIRST				{ $$ = SORTBY_NULLS_FIRST; }
  *****************************************************************************/
 
 CreateFunctionStmt:
-			CREATE opt_or_replace FUNCTION func_name func_args
+			CREATE opt_or_replace FUNCTION func_name func_args_with_defaults
 			RETURNS func_return createfunc_opt_list opt_definition
 				{
 					CreateFunctionStmt *n = makeNode(CreateFunctionStmt);
@@ -4182,7 +4183,7 @@ CreateFunctionStmt:
 					n->withClause = $9;
 					$$ = (Node *)n;
 				}
-			| CREATE opt_or_replace FUNCTION func_name func_args
+			| CREATE opt_or_replace FUNCTION func_name func_args_with_defaults
 			  RETURNS TABLE '(' table_func_column_list ')' createfunc_opt_list opt_definition
 				{
 					CreateFunctionStmt *n = makeNode(CreateFunctionStmt);
@@ -4195,7 +4196,7 @@ CreateFunctionStmt:
 					n->withClause = $12;
 					$$ = (Node *)n;
 				}
-			| CREATE opt_or_replace FUNCTION func_name func_args
+			| CREATE opt_or_replace FUNCTION func_name func_args_with_defaults
 			  createfunc_opt_list opt_definition
 				{
 					CreateFunctionStmt *n = makeNode(CreateFunctionStmt);
@@ -4223,6 +4224,21 @@ func_args_list:
 			| func_args_list ',' func_arg			{ $$ = lappend($1, $3); }
 		;
 
+/*
+ * func_args_with_defaults is separate because we only want to accept
+ * defaults in CREATE FUNCTION, not in ALTER etc.
+ */
+func_args_with_defaults:
+		'(' func_args_with_defaults_list ')'		{ $$ = $2; }
+			| '(' ')'								{ $$ = NIL; }
+		;
+
+func_args_with_defaults_list:
+		func_arg_with_default						{ $$ = list_make1( $1); }
+			| func_args_with_defaults_list ',' func_arg_with_default	{ $$ = lappend($1, $3); }
+		;
+
+
 /*
  * The style with arg_class first is SQL99 standard, but Oracle puts
  * param_name first; accept both since it's likely people will try both
@@ -4240,6 +4256,7 @@ func_arg:
 					n->name = $2;
 					n->argType = $3;
 					n->mode = $1;
+					n->defexpr = NULL;
 					$$ = n;
 				}
 			| param_name arg_class func_type
@@ -4248,6 +4265,7 @@ func_arg:
 					n->name = $1;
 					n->argType = $3;
 					n->mode = $2;
+					n->defexpr = NULL;
 					$$ = n;
 				}
 			| param_name func_type
@@ -4256,6 +4274,7 @@ func_arg:
 					n->name = $1;
 					n->argType = $2;
 					n->mode = FUNC_PARAM_IN;
+					n->defexpr = NULL;
 					$$ = n;
 				}
 			| arg_class func_type
@@ -4264,6 +4283,7 @@ func_arg:
 					n->name = NULL;
 					n->argType = $2;
 					n->mode = $1;
+					n->defexpr = NULL;
 					$$ = n;
 				}
 			| func_type
@@ -4272,6 +4292,7 @@ func_arg:
 					n->name = NULL;
 					n->argType = $1;
 					n->mode = FUNC_PARAM_IN;
+					n->defexpr = NULL;
 					$$ = n;
 				}
 		;
@@ -4322,6 +4343,23 @@ func_type:	Typename								{ $$ = $1; }
 				}
 		;
 
+func_arg_with_default:
+		func_arg
+			    { 
+				    $$ = $1;
+			    }
+		| func_arg DEFAULT a_expr
+			    {
+				    $$ = $1;
+				    $$->defexpr = $3;
+			    }
+		| func_arg '=' a_expr
+			    {
+				    $$ = $1;
+				    $$->defexpr = $3;
+			    }
+		;
+
 
 createfunc_opt_list:
 			/* Must be at least one to prevent conflict */

src/backend/parser/parse_func.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/parser/parse_func.c,v 1.207 2008/09/01 20:42:44 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/parser/parse_func.c,v 1.208 2008/12/04 17:51:26 petere Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -77,6 +77,7 @@ ParseFuncOrColumn(ParseState *pstate, List *funcname, List *fargs,
 	bool		retset;
 	int			nvargs;
 	FuncDetailCode fdresult;
+	List	   *argdefaults;
 
 	/*
 	 * Most of the rest of the parser just assumes that functions do not have
@@ -164,7 +165,7 @@ ParseFuncOrColumn(ParseState *pstate, List *funcname, List *fargs,
 	fdresult = func_get_detail(funcname, fargs, nargs, actual_arg_types,
 							   !func_variadic,
 							   &funcid, &rettype, &retset, &nvargs,
-							   &declared_arg_types);
+							   &declared_arg_types, &argdefaults);
 	if (fdresult == FUNCDETAIL_COERCION)
 	{
 		/*
@@ -234,6 +235,21 @@ ParseFuncOrColumn(ParseState *pstate, List *funcname, List *fargs,
 					 parser_errposition(pstate, location)));
 	}
 
+	/* add stored expressions as called values for arguments with defaults */
+	if (argdefaults)
+	{
+		ListCell  *lc;
+
+		foreach(lc, argdefaults)
+		{
+			Node	*expr = (Node *) lfirst(lc);
+    
+			fargs = lappend(fargs, expr);
+			actual_arg_types[nargs++] = exprType(expr);
+		}
+	}
+
+
 	/*
 	 * enforce consistency with polymorphic argument and return types,
 	 * possibly adjusting return type or declared_arg_types (which will be
@@ -729,7 +745,8 @@ func_get_detail(List *funcname,
 				Oid *rettype,	/* return value */
 				bool *retset,	/* return value */
 				int *nvargs,	/* return value */
-				Oid **true_typeids)		/* return value */
+				Oid **true_typeids,		/* return value */
+				List **argdefaults)	/* return value */
 {
 	FuncCandidateList raw_candidates;
 	FuncCandidateList best_candidate;
@@ -870,6 +887,8 @@ func_get_detail(List *funcname,
 		*funcid = best_candidate->oid;
 		*nvargs = best_candidate->nvargs;
 		*true_typeids = best_candidate->args;
+		if (argdefaults)
+			*argdefaults = best_candidate->argdefaults;
 
 		ftup = SearchSysCache(PROCOID,
 							  ObjectIdGetDatum(best_candidate->oid),

src/backend/tcop/utility.c

@@ -10,7 +10,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/tcop/utility.c,v 1.301 2008/11/07 18:25:06 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/tcop/utility.c,v 1.302 2008/12/04 17:51:26 petere Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -700,7 +700,7 @@ ProcessUtility(Node *parsetree,
 			break;
 
 		case T_CreateFunctionStmt:		/* CREATE FUNCTION */
-			CreateFunction((CreateFunctionStmt *) parsetree);
+			CreateFunction((CreateFunctionStmt *) parsetree, queryString);
 			break;
 
 		case T_AlterFunctionStmt:		/* ALTER FUNCTION */

src/backend/utils/adt/ruleutils.c

@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/adt/ruleutils.c,v 1.287 2008/10/06 20:29:38 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/adt/ruleutils.c,v 1.288 2008/12/04 17:51:27 petere Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -141,7 +141,8 @@ static char *pg_get_constraintdef_worker(Oid constraintId, bool fullCommand,
 static char *pg_get_expr_worker(text *expr, Oid relid, char *relname,
 				   int prettyFlags);
 static int print_function_arguments(StringInfo buf, HeapTuple proctup,
-						 bool print_table_args);
+						 bool print_table_args,
+						 bool full);
 static void print_function_rettype(StringInfo buf, HeapTuple proctup);
 static void make_ruledef(StringInfo buf, HeapTuple ruletup, TupleDesc rulettc,
 			 int prettyFlags);
@@ -1449,7 +1450,7 @@ pg_get_functiondef(PG_FUNCTION_ARGS)
 	nsp = get_namespace_name(proc->pronamespace);
 	appendStringInfo(&buf, "CREATE OR REPLACE FUNCTION %s(",
 					 quote_qualified_identifier(nsp, name));
-	(void) print_function_arguments(&buf, proctup, false);
+	(void) print_function_arguments(&buf, proctup, false, true);
 	appendStringInfoString(&buf, ")\n RETURNS ");
 	print_function_rettype(&buf, proctup);
 	appendStringInfo(&buf, "\n LANGUAGE %s\n",
@@ -1598,13 +1599,43 @@ pg_get_function_arguments(PG_FUNCTION_ARGS)
 	if (!HeapTupleIsValid(proctup))
 		elog(ERROR, "cache lookup failed for function %u", funcid);
 
-	(void) print_function_arguments(&buf, proctup, false);
+	(void) print_function_arguments(&buf, proctup, false, true);
 
 	ReleaseSysCache(proctup);
 
 	PG_RETURN_TEXT_P(string_to_text(buf.data));
 }
 
+/*
+ * pg_get_function_identity_arguments
+ *		Get a formatted list of arguments for a function.
+ *		This is everything that would go between the parentheses in
+ *		ALTER FUNCTION, etc. skip names and defaults/
+ */
+Datum
+pg_get_function_identity_arguments(PG_FUNCTION_ARGS)
+{
+	Oid			funcid = PG_GETARG_OID(0);
+	StringInfoData buf;
+	HeapTuple	proctup;
+
+	initStringInfo(&buf);
+
+	proctup = SearchSysCache(PROCOID,
+							 ObjectIdGetDatum(funcid),
+							 0, 0, 0);
+	if (!HeapTupleIsValid(proctup))
+		elog(ERROR, "cache lookup failed for function %u", funcid);
+
+	(void) print_function_arguments(&buf, proctup, false, false);
+
+	ReleaseSysCache(proctup);
+
+	PG_RETURN_TEXT_P(string_to_text(buf.data));
+}
+
+
+
 /*
  * pg_get_function_result
  *		Get a nicely-formatted version of the result type of a function.
@@ -1649,7 +1680,7 @@ print_function_rettype(StringInfo buf, HeapTuple proctup)
 	{
 		/* It might be a table function; try to print the arguments */
 		appendStringInfoString(&rbuf, "TABLE(");
-		ntabargs = print_function_arguments(&rbuf, proctup, true);
+		ntabargs = print_function_arguments(&rbuf, proctup, true, true);
 		if (ntabargs > 0)
 			appendStringInfoString(&rbuf, ")");
 		else
@@ -1672,10 +1703,12 @@ print_function_rettype(StringInfo buf, HeapTuple proctup)
  * append the desired subset of arguments to buf.  We print only TABLE
  * arguments when print_table_args is true, and all the others when it's false.
  * Function return value is the number of arguments printed.
+ * When full is false, then don't print argument names and argument defaults.
  */
 static int
 print_function_arguments(StringInfo buf, HeapTuple proctup,
-						 bool print_table_args)
+						 bool print_table_args,
+						 bool full)
 {
 	int			numargs;
 	Oid		   *argtypes;
@@ -1683,10 +1716,37 @@ print_function_arguments(StringInfo buf, HeapTuple proctup,
 	char	   *argmodes;
 	int			argsprinted;
 	int			i;
+	Datum		proargdefaults;
+	List	   *argdefaults;
+	int			nargdefaults;
+	bool		isnull;
+	List	   *dcontext = NIL;
 
 	numargs = get_func_arg_info(proctup,
 								&argtypes, &argnames, &argmodes);
 
+	proargdefaults = SysCacheGetAttr(PROCOID, proctup,
+									 Anum_pg_proc_proargdefaults, &isnull);
+	if (!isnull)
+	{
+		char	*str;
+
+		str = TextDatumGetCString(proargdefaults);
+		argdefaults = (List *) stringToNode(str);
+		Assert(IsA(argdefaults, List));
+		nargdefaults = list_length(argdefaults);
+	    
+		/* we will need deparse context */
+		//dcontext = deparse_context_for("", InvalidOid);
+		dcontext = NULL;
+		pfree(str);
+	}
+	else
+	{
+		argdefaults = NIL;
+		nargdefaults = 0;
+	}
+
 	argsprinted = 0;
 	for (i = 0; i < numargs; i++)
 	{
@@ -1723,9 +1783,19 @@ print_function_arguments(StringInfo buf, HeapTuple proctup,
 		if (argsprinted)
 			appendStringInfoString(buf, ", ");
 		appendStringInfoString(buf, modename);
-		if (argname && argname[0])
+		if (argname && argname[0] && full)
 			appendStringInfo(buf, "%s ", argname);
 		appendStringInfoString(buf, format_type_be(argtype));
+
+		/* search given default expression, expect less numargs */
+		if (nargdefaults > 0 && i >= (numargs - nargdefaults) && full)
+		{
+			Node	*expr;
+
+			expr = (Node *) list_nth(argdefaults, i - (numargs - nargdefaults));
+			appendStringInfo(buf, " DEFAULT %s",  deparse_expression(expr, dcontext, false, false));
+		}
+
 		argsprinted++;
 	}
 
@@ -6002,7 +6072,7 @@ generate_function_name(Oid funcid, int nargs, Oid *argtypes,
 	p_result = func_get_detail(list_make1(makeString(proname)),
 							   NIL, nargs, argtypes, false,
 							   &p_funcid, &p_rettype,
-							   &p_retset, &p_nvargs, &p_true_typeids);
+							   &p_retset, &p_nvargs, &p_true_typeids, NULL);
 	if ((p_result == FUNCDETAIL_NORMAL || p_result == FUNCDETAIL_AGGREGATE) &&
 		p_funcid == funcid)
 		nspname = NULL;

src/bin/pg_dump/pg_dump.c

@@ -12,7 +12,7 @@
  *	by PostgreSQL
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/bin/pg_dump/pg_dump.c,v 1.505 2008/11/09 21:24:32 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/bin/pg_dump/pg_dump.c,v 1.506 2008/12/04 17:51:27 petere Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -6733,13 +6733,15 @@ dumpFunc(Archive *fout, FuncInfo *finfo)
 	PQExpBuffer delqry;
 	PQExpBuffer asPart;
 	PGresult   *res;
-	char	   *funcsig;
+	char	   *funcsig;				/* identity signature */
+	char	   *funcfullsig;			/* full signature */
 	char	   *funcsig_tag;
 	int			ntups;
 	char	   *proretset;
 	char	   *prosrc;
 	char	   *probin;
 	char	   *funcargs;
+	char	   *funciargs;
 	char	   *funcresult;
 	char	   *proallargtypes;
 	char	   *proargmodes;
@@ -6782,6 +6784,7 @@ dumpFunc(Archive *fout, FuncInfo *finfo)
 		appendPQExpBuffer(query,
 						  "SELECT proretset, prosrc, probin, "
 						  "pg_catalog.pg_get_function_arguments(oid) as funcargs, "
+						  "pg_catalog.pg_get_function_identity_arguments(oid) as funciargs, "
 						  "pg_catalog.pg_get_function_result(oid) as funcresult, "
 						  "provolatile, proisstrict, prosecdef, "
 						  "proconfig, procost, prorows, "
@@ -6893,6 +6896,7 @@ dumpFunc(Archive *fout, FuncInfo *finfo)
 	if (g_fout->remoteVersion >= 80400)
 	{
 		funcargs = PQgetvalue(res, 0, PQfnumber(res, "funcargs"));
+		funciargs = PQgetvalue(res, 0, PQfnumber(res, "funciargs"));
 		funcresult = PQgetvalue(res, 0, PQfnumber(res, "funcresult"));
 		proallargtypes = proargmodes = proargnames = NULL;
 	}
@@ -6901,7 +6905,7 @@ dumpFunc(Archive *fout, FuncInfo *finfo)
 		proallargtypes = PQgetvalue(res, 0, PQfnumber(res, "proallargtypes"));
 		proargmodes = PQgetvalue(res, 0, PQfnumber(res, "proargmodes"));
 		proargnames = PQgetvalue(res, 0, PQfnumber(res, "proargnames"));
-		funcargs = funcresult = NULL;
+		funcargs = funciargs = funcresult = NULL;
 	}
 	provolatile = PQgetvalue(res, 0, PQfnumber(res, "provolatile"));
 	proisstrict = PQgetvalue(res, 0, PQfnumber(res, "proisstrict"));
@@ -7007,11 +7011,19 @@ dumpFunc(Archive *fout, FuncInfo *finfo)
 		}
 	}
 
-	if (funcargs)
-		funcsig = format_function_arguments(finfo, funcargs);
+	/* funcargs and funciargs are supported from 8.4 */
+	if (funciargs)
+	{
+		funcsig = format_function_arguments(finfo, funciargs);
+		funcfullsig = format_function_arguments(finfo, funcargs);
+	}
 	else
+	{
 		funcsig = format_function_arguments_old(finfo, nallargs, allargtypes,
 												argmodes, argnames);
+		funcfullsig = funcsig;
+	}
+
 	funcsig_tag = format_function_signature(finfo, false);
 
 	/*
@@ -7021,7 +7033,7 @@ dumpFunc(Archive *fout, FuncInfo *finfo)
 					  fmtId(finfo->dobj.namespace->dobj.name),
 					  funcsig);
 
-	appendPQExpBuffer(q, "CREATE FUNCTION %s ", funcsig);
+	appendPQExpBuffer(q, "CREATE FUNCTION %s ", funcfullsig);
 	if (funcresult)
 		appendPQExpBuffer(q, "RETURNS %s", funcresult);
 	else

src/include/catalog/catversion.h

@@ -37,7 +37,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.510 2008/12/03 13:28:53 heikki Exp $
+ * $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.511 2008/12/04 17:51:27 petere Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -53,6 +53,6 @@
  */
 
 /*							yyyymmddN */
-#define CATALOG_VERSION_NO	200812031
+#define CATALOG_VERSION_NO	200812041
 
 #endif

src/include/catalog/namespace.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/catalog/namespace.h,v 1.55 2008/07/16 01:30:23 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/catalog/namespace.h,v 1.56 2008/12/04 17:51:27 petere Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -30,6 +30,7 @@ typedef struct _FuncCandidateList
 	Oid			oid;			/* the function or operator's OID */
 	int			nargs;			/* number of arg types returned */
 	int			nvargs;			/* number of args to become variadic array */
+	List			*argdefaults;		/* list of parameter defaults */
 	Oid			args[1];		/* arg types --- VARIABLE LENGTH ARRAY */
 }	*FuncCandidateList;	/* VARIABLE LENGTH STRUCT */
 

src/include/catalog/pg_attribute.h

@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/catalog/pg_attribute.h,v 1.141 2008/11/09 21:24:33 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/catalog/pg_attribute.h,v 1.142 2008/12/04 17:51:27 petere Exp $
  *
  * NOTES
  *	  the genbki.sh script reads this file and generates .bki
@@ -300,15 +300,17 @@ DATA(insert ( 1247 tableoid			26 0  4  -7 0 -1 -1 t p i t f f t 0));
 { 1255, {"proretset"},			16, -1, 1, 11, 0, -1, -1, true, 'p', 'c', true, false, false, true, 0 }, \
 { 1255, {"provolatile"},		18, -1, 1, 12, 0, -1, -1, true, 'p', 'c', true, false, false, true, 0 }, \
 { 1255, {"pronargs"},			21, -1, 2, 13, 0, -1, -1, true, 'p', 's', true, false, false, true, 0 }, \
-{ 1255, {"prorettype"},			26, -1, 4, 14, 0, -1, -1, true, 'p', 'i', true, false, false, true, 0 }, \
-{ 1255, {"proargtypes"},		30, -1, -1, 15, 1, -1, -1, false, 'p', 'i', true, false, false, true, 0 }, \
-{ 1255, {"proallargtypes"},   1028, -1, -1, 16, 1, -1, -1, false, 'x', 'i', false, false, false, true, 0 }, \
-{ 1255, {"proargmodes"},	  1002, -1, -1, 17, 1, -1, -1, false, 'x', 'i', false, false, false, true, 0 }, \
-{ 1255, {"proargnames"},	  1009, -1, -1, 18, 1, -1, -1, false, 'x', 'i', false, false, false, true, 0 }, \
-{ 1255, {"prosrc"},				25, -1, -1, 19, 0, -1, -1, false, 'x', 'i', false, false, false, true, 0 }, \
-{ 1255, {"probin"},				17, -1, -1, 20, 0, -1, -1, false, 'x', 'i', false, false, false, true, 0 }, \
-{ 1255, {"proconfig"},		  1009, -1, -1, 21, 1, -1, -1, false, 'x', 'i', false, false, false, true, 0 }, \
-{ 1255, {"proacl"},			  1034, -1, -1, 22, 1, -1, -1, false, 'x', 'i', false, false, false, true, 0 }
+{ 1255, {"pronargdefaults"},		21, -1, 2, 14, 0, -1, -1, true, 'p', 's', true, false, false, true, 0 }, \
+{ 1255, {"prorettype"},			26, -1, 4, 15, 0, -1, -1, true, 'p', 'i', true, false, false, true, 0 }, \
+{ 1255, {"proargtypes"},		30, -1, -1, 16, 1, -1, -1, false, 'p', 'i', true, false, false, true, 0 }, \
+{ 1255, {"proallargtypes"},   1028, -1, -1, 17, 1, -1, -1, false, 'x', 'i', false, false, false, true, 0 }, \
+{ 1255, {"proargmodes"},	  1002, -1, -1, 18, 1, -1, -1, false, 'x', 'i', false, false, false, true, 0 }, \
+{ 1255, {"proargnames"},	  1009, -1, -1, 19, 1, -1, -1, false, 'x', 'i', false, false, false, true, 0 }, \
+{ 1255, {"proargdefaults"},		25, -1, -1, 20, 0, -1, -1, false, 'x', 'i', false, false, false, true, 0 }, \
+{ 1255, {"prosrc"},				25, -1, -1, 21, 0, -1, -1, false, 'x', 'i', false, false, false, true, 0 }, \
+{ 1255, {"probin"},				17, -1, -1, 22, 0, -1, -1, false, 'x', 'i', false, false, false, true, 0 }, \
+{ 1255, {"proconfig"},		  1009, -1, -1, 23, 1, -1, -1, false, 'x', 'i', false, false, false, true, 0 }, \
+{ 1255, {"proacl"},			  1034, -1, -1, 24, 1, -1, -1, false, 'x', 'i', false, false, false, true, 0 }
 
 DATA(insert ( 1255 proname			19 -1 NAMEDATALEN	1 0 -1 -1 f p c t f f t 0));
 DATA(insert ( 1255 pronamespace		26 -1 4   2 0 -1 -1 t p i t f f t 0));
@@ -323,15 +325,17 @@ DATA(insert ( 1255 proisstrict		16 -1 1  10 0 -1 -1 t p c t f f t 0));
 DATA(insert ( 1255 proretset		16 -1 1  11 0 -1 -1 t p c t f f t 0));
 DATA(insert ( 1255 provolatile		18 -1 1  12 0 -1 -1 t p c t f f t 0));
 DATA(insert ( 1255 pronargs			21 -1 2  13 0 -1 -1 t p s t f f t 0));
-DATA(insert ( 1255 prorettype		26 -1 4  14 0 -1 -1 t p i t f f t 0));
-DATA(insert ( 1255 proargtypes		30 -1 -1 15 1 -1 -1 f p i t f f t 0));
-DATA(insert ( 1255 proallargtypes 1028 -1 -1 16 1 -1 -1 f x i f f f t 0));
-DATA(insert ( 1255 proargmodes	  1002 -1 -1 17 1 -1 -1 f x i f f f t 0));
-DATA(insert ( 1255 proargnames	  1009 -1 -1 18 1 -1 -1 f x i f f f t 0));
-DATA(insert ( 1255 prosrc			25 -1 -1 19 0 -1 -1 f x i f f f t 0));
-DATA(insert ( 1255 probin			17 -1 -1 20 0 -1 -1 f x i f f f t 0));
-DATA(insert ( 1255 proconfig	  1009 -1 -1 21 1 -1 -1 f x i f f f t 0));
-DATA(insert ( 1255 proacl		  1034 -1 -1 22 1 -1 -1 f x i f f f t 0));
+DATA(insert ( 1255 pronargdefaults	21 -1 2  14 0 -1 -1 t p s t f f t 0));
+DATA(insert ( 1255 prorettype		26 -1 4  15 0 -1 -1 t p i t f f t 0));
+DATA(insert ( 1255 proargtypes		30 -1 -1 16 1 -1 -1 f p i t f f t 0));
+DATA(insert ( 1255 proallargtypes 1028 -1 -1 17 1 -1 -1 f x i f f f t 0));
+DATA(insert ( 1255 proargmodes	  1002 -1 -1 18 1 -1 -1 f x i f f f t 0));
+DATA(insert ( 1255 proargnames	  1009 -1 -1 19 1 -1 -1 f x i f f f t 0));
+DATA(insert ( 1255 proargdefaults	25 -1 -1 20 0 -1 -1 f x i f f f t 0));
+DATA(insert ( 1255 prosrc			25 -1 -1 21 0 -1 -1 f x i f f f t 0));
+DATA(insert ( 1255 probin			17 -1 -1 22 0 -1 -1 f x i f f f t 0));
+DATA(insert ( 1255 proconfig	  1009 -1 -1 23 1 -1 -1 f x i f f f t 0));
+DATA(insert ( 1255 proacl		  1034 -1 -1 24 1 -1 -1 f x i f f f t 0));
 DATA(insert ( 1255 ctid				27 0  6  -1 0 -1 -1 f p s t f f t 0));
 DATA(insert ( 1255 oid				26 0  4  -2 0 -1 -1 t p i t f f t 0));
 DATA(insert ( 1255 xmin				28 0  4  -3 0 -1 -1 t p i t f f t 0));

src/include/catalog/pg_class.h

@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/catalog/pg_class.h,v 1.108 2008/11/09 21:24:33 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/catalog/pg_class.h,v 1.109 2008/12/04 17:51:27 petere Exp $
  *
  * NOTES
  *	  the genbki.sh script reads this file and generates .bki
@@ -125,7 +125,7 @@ DATA(insert OID = 1247 (  pg_type		PGNSP 71 PGUID 0 1247 0 0 0 0 0 f f r 28 0 t
 DESCR("");
 DATA(insert OID = 1249 (  pg_attribute	PGNSP 75 PGUID 0 1249 0 0 0 0 0 f f r 17 0 f f f f f 3 _null_ _null_ ));
 DESCR("");
-DATA(insert OID = 1255 (  pg_proc		PGNSP 81 PGUID 0 1255 0 0 0 0 0 f f r 22 0 t f f f f 3 _null_ _null_ ));
+DATA(insert OID = 1255 (  pg_proc		PGNSP 81 PGUID 0 1255 0 0 0 0 0 f f r 24 0 t f f f f 3 _null_ _null_ ));
 DESCR("");
 DATA(insert OID = 1259 (  pg_class		PGNSP 83 PGUID 0 1259 0 0 0 0 0 f f r 24 0 t f f f f 3 _null_ _null_ ));
 DESCR("");

src/include/catalog/pg_proc_fn.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/catalog/pg_proc_fn.h,v 1.1 2008/03/27 03:57:34 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/catalog/pg_proc_fn.h,v 1.2 2008/12/04 17:51:27 petere Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -33,7 +33,8 @@ extern Oid ProcedureCreate(const char *procedureName,
 				Datum parameterNames,
 				Datum proconfig,
 				float4 procost,
-				float4 prorows);
+				float4 prorows,
+				List *parameterDefaults);
 
 extern bool function_parse_error_transpose(const char *prosrc);
 

src/include/commands/defrem.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/commands/defrem.h,v 1.89 2008/06/14 18:04:34 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/commands/defrem.h,v 1.90 2008/12/04 17:51:27 petere Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -45,7 +45,7 @@ extern char *ChooseRelationName(const char *name1, const char *name2,
 extern Oid	GetDefaultOpClass(Oid type_id, Oid am_id);
 
 /* commands/functioncmds.c */
-extern void CreateFunction(CreateFunctionStmt *stmt);
+extern void CreateFunction(CreateFunctionStmt *stmt, const char *queryString);
 extern void RemoveFunction(RemoveFuncStmt *stmt);
 extern void RemoveFunctionById(Oid funcOid);
 extern void SetFunctionReturnType(Oid funcOid, Oid newRetType);

src/include/nodes/parsenodes.h

@@ -13,7 +13,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/nodes/parsenodes.h,v 1.380 2008/12/04 11:42:24 heikki Exp $
+ * $PostgreSQL: pgsql/src/include/nodes/parsenodes.h,v 1.381 2008/12/04 17:51:27 petere Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1686,6 +1686,7 @@ typedef struct FunctionParameter
 	char	   *name;			/* parameter name, or NULL if not given */
 	TypeName   *argType;		/* TypeName for parameter type */
 	FunctionParameterMode mode; /* IN/OUT/INOUT */
+	Node		*defexpr;	/* Default expression, or NULL if not given */
 } FunctionParameter;
 
 typedef struct AlterFunctionStmt

src/include/parser/parse_func.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/parser/parse_func.h,v 1.60 2008/07/16 01:30:23 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/parser/parse_func.h,v 1.61 2008/12/04 17:51:27 petere Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -49,7 +49,8 @@ extern Node *ParseFuncOrColumn(ParseState *pstate,
 extern FuncDetailCode func_get_detail(List *funcname, List *fargs,
 				int nargs, Oid *argtypes, bool expand_variadic,
 				Oid *funcid, Oid *rettype,
-				bool *retset, int *nvargs, Oid **true_typeids);
+				bool *retset, int *nvargs, Oid **true_typeids,
+				List **argdefaults);
 
 extern int func_match_argtypes(int nargs,
 					Oid *input_typeids,

src/include/utils/builtins.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/utils/builtins.h,v 1.326 2008/11/03 20:17:20 adunstan Exp $
+ * $PostgreSQL: pgsql/src/include/utils/builtins.h,v 1.327 2008/12/04 17:51:28 petere Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -553,6 +553,7 @@ extern Datum pg_get_userbyid(PG_FUNCTION_ARGS);
 extern Datum pg_get_serial_sequence(PG_FUNCTION_ARGS);
 extern Datum pg_get_functiondef(PG_FUNCTION_ARGS);
 extern Datum pg_get_function_arguments(PG_FUNCTION_ARGS);
+extern Datum pg_get_function_identity_arguments(PG_FUNCTION_ARGS);
 extern Datum pg_get_function_result(PG_FUNCTION_ARGS);
 extern char *deparse_expression(Node *expr, List *dpcontext,
 				   bool forceprefix, bool showimplicit);

src/test/regress/expected/opr_sanity.out

@@ -61,6 +61,14 @@ WHERE prosrc IS NULL OR prosrc = '' OR prosrc = '-';
 -----+---------
 (0 rows)
 
+-- pronargdefaults should be 0 iff proargdefaults is null
+SELECT p.oid, p.proname
+FROM pg_proc AS p
+WHERE pronargdefaults <> 0 OR proargdefaults IS NOT NULL;
+ oid | proname 
+-----+---------
+(0 rows)
+
 -- probin should be non-empty for C functions, null everywhere else
 SELECT p1.oid, p1.proname
 FROM pg_proc as p1

src/test/regress/expected/polymorphism.out

@@ -776,3 +776,190 @@ select pg_typeof(myleast(10, 1, 20, 33));  -- polymorphic input
  integer
 (1 row)
 
+-- test functions with parameter defaults
+-- test basic functionality
+create function dfunc(a int = 1, int = 2) returns int as $$
+  select $1 + $2;
+$$ language sql;
+select dfunc();
+ dfunc 
+-------
+     3
+(1 row)
+
+select dfunc(10);
+ dfunc 
+-------
+    12
+(1 row)
+
+select dfunc(10, 20);
+ dfunc 
+-------
+    30
+(1 row)
+
+drop function dfunc();  -- fail
+ERROR:  function dfunc() does not exist
+drop function dfunc(int);  -- fail
+ERROR:  function dfunc(integer) does not exist
+drop function dfunc(int, int);  -- ok
+-- fail, gap in arguments with defaults
+create function dfunc(a int = 1, b int) returns int as $$
+  select $1 + $2;
+$$ language sql;
+ERROR:  parameter without default value specified after parameter with default value
+-- check implicit coercion 
+create function dfunc(a int DEFAULT 1.0, int DEFAULT '-1') returns int as $$
+  select $1 + $2;
+$$ language sql;
+select dfunc();
+ dfunc 
+-------
+     0
+(1 row)
+
+create function dfunc(a text DEFAULT 'Hello', b text DEFAULT 'World') returns text as $$
+  select $1 || ', ' || $2;
+$$ language sql;
+select dfunc();  -- fail; which dfunc should be called? int or text
+ERROR:  functions with parameter defaults dfunc(text, text) and dfunc(integer, integer) are ambiguous
+select dfunc('Hi');  -- ok
+   dfunc   
+-----------
+ Hi, World
+(1 row)
+
+select dfunc('Hi', 'City');  -- ok
+  dfunc   
+----------
+ Hi, City
+(1 row)
+
+select dfunc(0);  -- ok
+ dfunc 
+-------
+    -1
+(1 row)
+
+select dfunc(10, 20);  -- ok
+ dfunc 
+-------
+    30
+(1 row)
+
+drop function dfunc(int, int);
+drop function dfunc(text, text);
+create function dfunc(int = 1, int = 2) returns int as $$
+  select 2; 
+$$ language sql;
+create function dfunc(int = 1, int = 2, int = 3, int = 4) returns int as $$
+  select 4;
+$$ language sql;
+-- Now, dfunc(nargs = 2) and dfunc(nargs = 4) are ambiguous when called
+-- with 0 or 1 arguments.  For 2 arguments, a normall call of
+-- dfunc(nargs = 2) takes place.
+select dfunc();  -- fail
+ERROR:  functions with parameter defaults dfunc(integer, integer, integer, integer) and dfunc(integer, integer) are ambiguous
+select dfunc(1);  -- fail
+ERROR:  functions with parameter defaults dfunc(integer, integer, integer, integer) and dfunc(integer, integer) are ambiguous
+select dfunc(1, 2);  -- ok
+ dfunc 
+-------
+     2
+(1 row)
+
+select dfunc(1, 2, 3);  -- ok
+ dfunc 
+-------
+     4
+(1 row)
+
+select dfunc(1, 2, 3, 4);  -- ok
+ dfunc 
+-------
+     4
+(1 row)
+
+drop function dfunc(int, int);
+drop function dfunc(int, int, int, int);
+-- default values are not allowed for output parameters
+create function dfunc(out int = 20) returns int as $$
+  select 1; 
+$$ language sql;
+ERROR:  only IN and INOUT parameters can have default values
+-- polymorphic parameter test
+create function dfunc(anyelement = 'World'::text) returns text as $$
+  select 'Hello, ' || $1::text;
+$$ language sql;
+select dfunc();
+    dfunc     
+--------------
+ Hello, World
+(1 row)
+
+select dfunc(0);
+  dfunc   
+----------
+ Hello, 0
+(1 row)
+
+select dfunc(to_date('20081215','YYYYMMDD'));
+       dfunc       
+-------------------
+ Hello, 12-15-2008
+(1 row)
+
+select dfunc('City'::text);
+    dfunc    
+-------------
+ Hello, City
+(1 row)
+
+drop function dfunc(anyelement);
+-- check null values
+create function dfunc(int = null, int = null, int = null) returns int[] as $$
+  select array[$1, $2, $3];
+$$ language sql;
+select dfunc(1);
+     dfunc     
+---------------
+ {1,NULL,NULL}
+(1 row)
+
+select dfunc(1, 2);
+   dfunc    
+------------
+ {1,2,NULL}
+(1 row)
+
+select dfunc(1, 2, 3);
+  dfunc  
+---------
+ {1,2,3}
+(1 row)
+
+drop function dfunc(int, int, int);
+-- The conflict detection algorithm doesn't consider the actual parameter
+-- types.  It detects any possible conflict for n arguments for some
+-- function.  This is unwanted behavior, but solving it needs a move of
+-- coercion routines.
+create function dfunc(int = 1, int = 2, int = 3) returns int as $$
+  select 3;
+$$ language sql;
+create function dfunc(int = 1, int = 2) returns int as $$
+  select 2;
+$$ language sql;
+-- for n = 1 dfunc(narg=2) and dfunc(narg=3) are ambiguous
+select dfunc(1);  -- fail
+ERROR:  functions with parameter defaults dfunc(integer, integer, integer) and dfunc(integer, integer) are ambiguous
+create function dfunc(text) returns text as $$
+  select $1;
+$$ language sql;
+-- Will fail, it detects ambiguity between dfunc(int, int, int) and
+-- dfunc(int, int), but dfunc(text) isn't in conflict with either.
+select dfunc('Hi');
+ERROR:  functions with parameter defaults dfunc(integer, integer, integer) and dfunc(integer, integer) are ambiguous
+drop function dfunc(int, int, int);
+drop function dfunc(int, int);
+drop function dfunc(text);

src/test/regress/sql/opr_sanity.sql

@@ -62,6 +62,11 @@ SELECT p1.oid, p1.proname
 FROM pg_proc as p1
 WHERE prosrc IS NULL OR prosrc = '' OR prosrc = '-';
 
+-- pronargdefaults should be 0 iff proargdefaults is null
+SELECT p.oid, p.proname
+FROM pg_proc AS p
+WHERE pronargdefaults <> 0 OR proargdefaults IS NOT NULL;
+
 -- probin should be non-empty for C functions, null everywhere else
 SELECT p1.oid, p1.proname
 FROM pg_proc as p1

src/test/regress/sql/polymorphism.sql

@@ -480,3 +480,117 @@ select pg_typeof('' || '');       -- text
 select pg_typeof(pg_typeof(0));   -- regtype
 select pg_typeof(array[1.2,55.5]); -- numeric[]
 select pg_typeof(myleast(10, 1, 20, 33));  -- polymorphic input
+
+-- test functions with parameter defaults
+-- test basic functionality
+create function dfunc(a int = 1, int = 2) returns int as $$
+  select $1 + $2;
+$$ language sql;
+
+select dfunc();
+select dfunc(10);
+select dfunc(10, 20);
+
+drop function dfunc();  -- fail
+drop function dfunc(int);  -- fail
+drop function dfunc(int, int);  -- ok
+
+-- fail, gap in arguments with defaults
+create function dfunc(a int = 1, b int) returns int as $$
+  select $1 + $2;
+$$ language sql;
+
+-- check implicit coercion 
+create function dfunc(a int DEFAULT 1.0, int DEFAULT '-1') returns int as $$
+  select $1 + $2;
+$$ language sql;
+select dfunc();
+create function dfunc(a text DEFAULT 'Hello', b text DEFAULT 'World') returns text as $$
+  select $1 || ', ' || $2;
+$$ language sql;
+
+select dfunc();  -- fail; which dfunc should be called? int or text
+select dfunc('Hi');  -- ok
+select dfunc('Hi', 'City');  -- ok
+select dfunc(0);  -- ok
+select dfunc(10, 20);  -- ok
+
+drop function dfunc(int, int);
+drop function dfunc(text, text);
+
+create function dfunc(int = 1, int = 2) returns int as $$
+  select 2; 
+$$ language sql;
+
+create function dfunc(int = 1, int = 2, int = 3, int = 4) returns int as $$
+  select 4;
+$$ language sql;
+
+-- Now, dfunc(nargs = 2) and dfunc(nargs = 4) are ambiguous when called
+-- with 0 or 1 arguments.  For 2 arguments, a normall call of
+-- dfunc(nargs = 2) takes place.
+
+select dfunc();  -- fail
+select dfunc(1);  -- fail
+select dfunc(1, 2);  -- ok
+select dfunc(1, 2, 3);  -- ok
+select dfunc(1, 2, 3, 4);  -- ok
+
+drop function dfunc(int, int);
+drop function dfunc(int, int, int, int);
+
+-- default values are not allowed for output parameters
+create function dfunc(out int = 20) returns int as $$
+  select 1; 
+$$ language sql;
+
+-- polymorphic parameter test
+create function dfunc(anyelement = 'World'::text) returns text as $$
+  select 'Hello, ' || $1::text;
+$$ language sql;
+
+select dfunc();
+select dfunc(0);
+select dfunc(to_date('20081215','YYYYMMDD'));
+select dfunc('City'::text);
+
+drop function dfunc(anyelement);
+
+-- check null values
+create function dfunc(int = null, int = null, int = null) returns int[] as $$
+  select array[$1, $2, $3];
+$$ language sql;
+
+select dfunc(1);
+select dfunc(1, 2);
+select dfunc(1, 2, 3);
+
+drop function dfunc(int, int, int);
+
+-- The conflict detection algorithm doesn't consider the actual parameter
+-- types.  It detects any possible conflict for n arguments for some
+-- function.  This is unwanted behavior, but solving it needs a move of
+-- coercion routines.
+
+create function dfunc(int = 1, int = 2, int = 3) returns int as $$
+  select 3;
+$$ language sql;
+
+create function dfunc(int = 1, int = 2) returns int as $$
+  select 2;
+$$ language sql;
+
+-- for n = 1 dfunc(narg=2) and dfunc(narg=3) are ambiguous
+select dfunc(1);  -- fail
+
+create function dfunc(text) returns text as $$
+  select $1;
+$$ language sql;
+
+-- Will fail, it detects ambiguity between dfunc(int, int, int) and
+-- dfunc(int, int), but dfunc(text) isn't in conflict with either.
+select dfunc('Hi');
+
+drop function dfunc(int, int, int);
+drop function dfunc(int, int);
+drop function dfunc(text);