Re: AW: [HACKERS] Re: Support for %TYPE in CREATE FUNCTION

Zeugswetter Andreas SB <ZeugswetterA(at)wien(dot)spardat(dot)at> writes:

> > > AND expect it to do more than that. So a NOTICE at the
> > > actual usage, telling that x%TYPE for y got resolved to
> > > basetype z and will currently NOT follow later changes to x
> > > should do it.
> >
> > So if you could implement it like that, we will be VERY happy.
>
> I also like that approach.

Well, if it helps, here is the patch again, with the NOTICE.

Ian

Index: doc/src/sgml/ref/create_function.sgml
===================================================================
RCS file: /home/projects/pgsql/cvsroot/pgsql/doc/src/sgml/ref/create_function.sgml,v
retrieving revision 1.23
diff -u -p -r1.23 create_function.sgml
--- doc/src/sgml/ref/create_function.sgml 2001/05/19 09:01:10 1.23
+++ doc/src/sgml/ref/create_function.sgml 2001/06/01 16:52:56
@@ -55,10 +55,16 @@ CREATE FUNCTION <replaceable class="para
<listitem>
<para>
The data type(s) of the function's arguments, if any. The
- input types may be base or complex types, or
- <literal>opaque</literal>. <literal>Opaque</literal> indicates
+ input types may be base or complex types,
+ <literal>opaque</literal>, or the same as the type of an
+ existing column. <literal>Opaque</literal> indicates
that the function accepts arguments of a non-SQL type such as
<type>char *</type>.
+ The type of a column is indicated using <replaceable
+ class="parameter">tablename</replaceable>.<replaceable
+ class="parameter">columnname</replaceable><literal>%TYPE</literal>;
+ using this can sometimes help make a function independent from
+ changes to the definition of a table.
</para>
</listitem>
</varlistentry>
@@ -69,8 +75,10 @@ CREATE FUNCTION <replaceable class="para
<listitem>
<para>
The return data type. The output type may be specified as a
- base type, complex type, <literal>setof</literal> type, or
- <literal>opaque</literal>. The <literal>setof</literal>
+ base type, complex type, <literal>setof</literal> type,
+ <literal>opaque</literal>, or the same as the type of an
+ existing column.
+ The <literal>setof</literal>
modifier indicates that the function will return a set of
items, rather than a single item. Functions with a declared
return type of <literal>opaque</literal> do not return a value.
Index: src/backend/parser/analyze.c
===================================================================
RCS file: /home/projects/pgsql/cvsroot/pgsql/src/backend/parser/analyze.c,v
retrieving revision 1.187
diff -u -p -r1.187 analyze.c
--- src/backend/parser/analyze.c 2001/05/22 16:37:15 1.187
+++ src/backend/parser/analyze.c 2001/06/01 16:52:58
@@ -29,6 +29,7 @@
#include "parser/parse_relation.h"
#include "parser/parse_target.h"
#include "parser/parse_type.h"
+#include "parser/parse_expr.h"
#include "rewrite/rewriteManip.h"
#include "utils/builtins.h"
#include "utils/fmgroids.h"
@@ -51,7 +52,10 @@ static Node *transformSetOperationTree(P
static Query *transformUpdateStmt(ParseState *pstate, UpdateStmt *stmt);
static Query *transformCreateStmt(ParseState *pstate, CreateStmt *stmt);
static Query *transformAlterTableStmt(ParseState *pstate, AlterTableStmt *stmt);
+static Node *transformTypeRefs(ParseState *pstate, Node *stmt);

+static void transformTypeRefsList(ParseState *pstate, List *l);
+static void transformTypeRef(ParseState *pstate, TypeName *tn);
static List *getSetColTypes(ParseState *pstate, Node *node);
static void transformForUpdate(Query *qry, List *forUpdate);
static void transformFkeyGetPrimaryKey(FkConstraint *fkconstraint, Oid *pktypoid);
@@ -232,6 +236,17 @@ transformStmt(ParseState *pstate, Node *
(SelectStmt *) parseTree);
break;

+ /*
+ * Convert use of %TYPE in statements where it is permitted.
+ */
+ case T_ProcedureStmt:
+ case T_CommentStmt:
+ case T_RemoveFuncStmt:
+ case T_DefineStmt:
+ result = makeNode(Query);
+ result->commandType = CMD_UTILITY;
+ result->utilityStmt = transformTypeRefs(pstate, parseTree);
+ break;

default:

@@ -2686,6 +2701,107 @@ transformAlterTableStmt(ParseState *psta
}
qry->utilityStmt = (Node *) stmt;
return qry;
+}
+
+/*
+ * Transform uses of %TYPE in a statement.
+ */
+static Node *
+transformTypeRefs(ParseState *pstate, Node *stmt)
+{
+ switch (nodeTag(stmt))
+ {
+ case T_ProcedureStmt:
+ {
+ ProcedureStmt *ps = (ProcedureStmt *) stmt;
+
+ transformTypeRefsList(pstate, ps->argTypes);
+ transformTypeRef(pstate, (TypeName *) ps->returnType);
+ transformTypeRefsList(pstate, ps->withClause);
+ }
+ break;
+
+ case T_CommentStmt:
+ {
+ CommentStmt *cs = (CommentStmt *) stmt;
+
+ transformTypeRefsList(pstate, cs->objlist);
+ }
+ break;
+
+ case T_RemoveFuncStmt:
+ {
+ RemoveFuncStmt *rs = (RemoveFuncStmt *) stmt;
+
+ transformTypeRefsList(pstate, rs->args);
+ }
+ break;
+
+ case T_DefineStmt:
+ {
+ DefineStmt *ds = (DefineStmt *) stmt;
+ List *ele;
+
+ foreach(ele, ds->definition)
+ {
+ DefElem *de = (DefElem *) lfirst(ele);
+
+ if (de->arg != NULL
+ && IsA(de->arg, TypeName))
+ {
+ transformTypeRef(pstate, (TypeName *) de->arg);
+ }
+ }
+ }
+ break;
+
+ default:
+ elog(ERROR, "Unsupported type %d in transformTypeRefs",
+ nodeTag(stmt));
+ break;
+ }
+
+ return stmt;
+}
+
+/*
+ * Transform uses of %TYPE in a list.
+ */
+static void
+transformTypeRefsList(ParseState *pstate, List *l)
+{
+ List *ele;
+
+ foreach(ele, l)
+ {
+ if (IsA(lfirst(ele), TypeName))
+ transformTypeRef(pstate, (TypeName *) lfirst(ele));
+ }
+}
+
+/*
+ * Transform a TypeName to not use %TYPE.
+ */
+static void
+transformTypeRef(ParseState *pstate, TypeName *tn)
+{
+ Attr *att;
+ Node *n;
+ Var *v;
+ char *tyn;
+
+ if (tn->attrname == NULL)
+ return;
+ att = makeAttr(tn->name, tn->attrname);
+ n = transformExpr(pstate, (Node *) att, EXPR_COLUMN_FIRST);
+ if (! IsA(n, Var))
+ elog(ERROR, "unsupported expression in %%TYPE");
+ v = (Var *) n;
+ tyn = typeidTypeName(v->vartype);
+ elog(NOTICE, "%s.%s%%TYPE converted to %s", tn->name, tn->attrname, tyn);
+ tn->name = tyn;
+ tn->typmod = v->vartypmod;
+ tn->attrname = NULL;
}

/* exported so planner can check again after rewriting, query pullup, etc */
Index: src/backend/parser/gram.y
===================================================================
RCS file: /home/projects/pgsql/cvsroot/pgsql/src/backend/parser/gram.y,v
retrieving revision 2.227
diff -u -p -r2.227 gram.y
--- src/backend/parser/gram.y 2001/05/27 09:59:29 2.227
+++ src/backend/parser/gram.y 2001/06/01 16:53:02
@@ -192,7 +192,7 @@ static void doNegateFloat(Value *v);
def_list, opt_indirection, group_clause, TriggerFuncArgs,
select_limit, opt_select_limit

-%type <typnam> func_arg, func_return, aggr_argtype
+%type <typnam> func_arg, func_return, func_type, aggr_argtype

%type <boolean> opt_arg, TriggerForOpt, TriggerForType, OptTemp

@@ -2490,7 +2490,7 @@ func_args_list: func_arg
{ $$ = lappend($1, $3); }
;

-func_arg: opt_arg Typename
+func_arg: opt_arg func_type
{
/* We can catch over-specified arguments here if we want to,
* but for now better to silently swallow typmod, etc.
@@ -2498,7 +2498,7 @@ func_arg: opt_arg Typename
*/
$$ = $2;
}
- | Typename
+ | func_type
{
$$ = $1;
}
@@ -2526,7 +2526,7 @@ func_as: Sconst
{ $$ = makeList2(makeString($1), makeString($3)); }
;

-func_return: Typename
+func_return: func_type
{
/* We can catch over-specified arguments here if we want to,
* but for now better to silently swallow typmod, etc.
@@ -2536,6 +2536,18 @@ func_return: Typename
}
;

+func_type: Typename
+ {
+ $$ = $1;
+ }
+ | IDENT '.' ColId '%' TYPE_P
+ {
+ $$ = makeNode(TypeName);
+ $$->name = $1;
+ $$->typmod = -1;
+ $$->attrname = $3;
+ }
+ ;

/*****************************************************************************
*
Index: src/backend/parser/parse_expr.c
===================================================================
RCS file: /home/projects/pgsql/cvsroot/pgsql/src/backend/parser/parse_expr.c,v
retrieving revision 1.96
diff -u -p -r1.96 parse_expr.c
--- src/backend/parser/parse_expr.c 2001/05/21 18:42:08 1.96
+++ src/backend/parser/parse_expr.c 2001/06/01 16:53:03
@@ -942,6 +942,7 @@ parser_typecast_expression(ParseState *p
char *
TypeNameToInternalName(TypeName *typename)
{
+ Assert(typename->attrname == NULL);
if (typename->arrayBounds != NIL)
{

Index: src/include/nodes/parsenodes.h
===================================================================
RCS file: /home/projects/pgsql/cvsroot/pgsql/src/include/nodes/parsenodes.h,v
retrieving revision 1.129
diff -u -p -r1.129 parsenodes.h
--- src/include/nodes/parsenodes.h 2001/05/21 18:42:08 1.129
+++ src/include/nodes/parsenodes.h 2001/06/01 16:53:09
@@ -951,6 +951,7 @@ typedef struct TypeName
bool setof; /* is a set? */
int32 typmod; /* type modifier */
List *arrayBounds; /* array bounds */
+ char *attrname; /* field name when using %TYPE */
} TypeName;

/*
Index: src/test/regress/input/create_function_2.source
===================================================================
RCS file: /home/projects/pgsql/cvsroot/pgsql/src/test/regress/input/create_function_2.source,v
retrieving revision 1.12
diff -u -p -r1.12 create_function_2.source
--- src/test/regress/input/create_function_2.source 2000/11/20 20:36:54 1.12
+++ src/test/regress/input/create_function_2.source 2001/06/01 16:53:18
@@ -13,6 +13,12 @@ CREATE FUNCTION hobby_construct(text, te
LANGUAGE 'sql';


+CREATE FUNCTION hobbies_by_name(hobbies_r.name%TYPE)
+ RETURNS hobbies_r.person%TYPE
+ AS 'select person from hobbies_r where name = $1'
+ LANGUAGE 'sql';
+
+
CREATE FUNCTION equipment(hobbies_r)
RETURNS setof equipment_r
AS 'select * from equipment_r where hobby = $1.name'
Index: src/test/regress/input/misc.source
===================================================================
RCS file: /home/projects/pgsql/cvsroot/pgsql/src/test/regress/input/misc.source,v
retrieving revision 1.14
diff -u -p -r1.14 misc.source
--- src/test/regress/input/misc.source 2000/11/20 20:36:54 1.14
+++ src/test/regress/input/misc.source 2001/06/01 16:53:18
@@ -214,6 +214,7 @@ SELECT user_relns() AS user_relns

--SELECT name(equipment(hobby_construct(text 'skywalking', text 'mer'))) AS equip_name;

+SELECT hobbies_by_name('basketball');

--
-- check that old-style C functions work properly with TOASTed values
Index: src/test/regress/output/create_function_2.source
===================================================================
RCS file: /home/projects/pgsql/cvsroot/pgsql/src/test/regress/output/create_function_2.source,v
retrieving revision 1.13
diff -u -p -r1.13 create_function_2.source
--- src/test/regress/output/create_function_2.source 2000/11/20 20:36:54 1.13
+++ src/test/regress/output/create_function_2.source 2001/06/01 16:53:18
@@ -9,6 +9,12 @@ CREATE FUNCTION hobby_construct(text, te
RETURNS hobbies_r
AS 'select $1 as name, $2 as hobby'
LANGUAGE 'sql';
+CREATE FUNCTION hobbies_by_name(hobbies_r.name%TYPE)
+ RETURNS hobbies_r.person%TYPE
+ AS 'select person from hobbies_r where name = $1'
+ LANGUAGE 'sql';
+NOTICE: hobbies_r.name%TYPE converted to text
+NOTICE: hobbies_r.person%TYPE converted to text
CREATE FUNCTION equipment(hobbies_r)
RETURNS setof equipment_r
AS 'select * from equipment_r where hobby = $1.name'
Index: src/test/regress/output/misc.source
===================================================================
RCS file: /home/projects/pgsql/cvsroot/pgsql/src/test/regress/output/misc.source,v
retrieving revision 1.27
diff -u -p -r1.27 misc.source
--- src/test/regress/output/misc.source 2000/11/20 20:36:54 1.27
+++ src/test/regress/output/misc.source 2001/06/01 16:53:18
@@ -656,6 +656,12 @@ SELECT user_relns() AS user_relns
(90 rows)

--SELECT name(equipment(hobby_construct(text 'skywalking', text 'mer'))) AS equip_name;
+SELECT hobbies_by_name('basketball');
+ hobbies_by_name
+-----------------
+ joe
+(1 row)
+
--
-- check that old-style C functions work properly with TOASTed values
--