Re: Support for %TYPE in CREATE FUNCTION - Mailing list pgsql-hackers

Sorry, looks like this patch has to be rejected because it can not
handle table changes.

> This patch adds support for %TYPE in CREATE FUNCTION argument and
> return types.
>
> %TYPE is already supported by PL/pgSQL when declaring variables.
> However, that does not help with the argument and return types in
> CREATE FUNCTION.
>
> Using %TYPE makes it easier to write a function which is independent
> of the definition of a table.  That is, minor changes to the types
> used in the table may not require changes to the function.
>
> For example, this trivial function will work whenever `table' which
> has columns named `name' and `value', no matter what the types of the
> columns are.
>
> CREATE FUNCTION lookup (table.name%TYPE)
>    RETURNS table.value%TYPE
>    AS 'select value from table where name = $1'
>    LANGUAGE 'sql';
>
> This patch includes changes to the testsuite and the documentation.
>
> This work was sponsored by Zembu.
>
> Ian
>
> Index: src/include/nodes/parsenodes.h
> ===================================================================
> RCS file: /home/projects/pgsql/cvsroot/pgsql/src/include/nodes/parsenodes.h,v
> retrieving revision 1.126
> diff -p -u -r1.126 parsenodes.h
> --- src/include/nodes/parsenodes.h    2001/03/23 04:49:56    1.126
> +++ src/include/nodes/parsenodes.h    2001/04/28 03:38:21
> @@ -945,6 +945,7 @@ 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/backend/parser/analyze.c
> ===================================================================
> RCS file: /home/projects/pgsql/cvsroot/pgsql/src/backend/parser/analyze.c,v
> retrieving revision 1.183
> diff -p -u -r1.183 analyze.c
> --- src/backend/parser/analyze.c    2001/03/22 06:16:15    1.183
> +++ src/backend/parser/analyze.c    2001/04/28 03:38:23
> @@ -27,6 +27,7 @@
>  #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"
> @@ -49,7 +50,10 @@ 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);
> @@ -230,6 +234,18 @@ 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:
>
>              /*
> @@ -2607,6 +2623,104 @@ 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;
> +
> +    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;
> +    tn->name = typeidTypeName(v->vartype);
> +    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 2.221
> diff -p -u -r2.221 gram.y
> --- src/backend/parser/gram.y    2001/02/18 18:06:10    2.221
> +++ src/backend/parser/gram.y    2001/04/28 03:38:26
> @@ -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
>
> @@ -2462,7 +2462,7 @@ func_args_list:  func_arg
>                  {    $$ = lappend($1, $3); }
>          ;
>
> -func_arg:  opt_arg Typename
> +func_arg:  opt_arg func_type
>                  {
>                      /* We can catch over-specified arguments here if we want to,
>                       * but for now better to silently swallow typmod, etc.
> @@ -2470,7 +2470,7 @@ func_arg:  opt_arg Typename
>                       */
>                      $$ = $2;
>                  }
> -        | Typename
> +        | func_type
>                  {
>                      $$ = $1;
>                  }
> @@ -2498,7 +2498,7 @@ func_as: Sconst
>                  {     $$ = 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.
> @@ -2508,6 +2508,18 @@ 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 1.92
> diff -p -u -r1.92 parse_expr.c
> --- src/backend/parser/parse_expr.c    2001/03/22 03:59:41    1.92
> +++ src/backend/parser/parse_expr.c    2001/04/28 03:38:26
> @@ -939,6 +939,7 @@ parser_typecast_expression(ParseState *p
>  char *
>  TypeNameToInternalName(TypeName *typename)
>  {
> +    Assert(typename->attrname == NULL);
>      if (typename->arrayBounds != NIL)
>      {
>
> 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 -p -u -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    2001/04/28 03:38:27
> @@ -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 -p -u -r1.14 misc.source
> --- src/test/regress/input/misc.source    2000/11/20 20:36:54    1.14
> +++ src/test/regress/input/misc.source    2001/04/28 03:38:28
> @@ -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 -p -u -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    2001/04/28 03:38:28
> @@ -9,6 +9,10 @@ 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';
>  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 -p -u -r1.27 misc.source
> --- src/test/regress/output/misc.source    2000/11/20 20:36:54    1.27
> +++ src/test/regress/output/misc.source    2001/04/28 03:38:28
> @@ -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
>  --
> 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 1.21
> diff -p -u -r1.21 create_function.sgml
> --- doc/src/sgml/ref/create_function.sgml    2000/12/25 23:15:26    1.21
> +++ doc/src/sgml/ref/create_function.sgml    2001/04/28 03:38:31
> @@ -58,10 +58,16 @@ 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
> -    <firstterm>opaque</firstterm>.
> +    The input types may be base or complex types,
> +    <firstterm>opaque</firstterm>, 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>
> @@ -72,7 +78,8 @@ CREATE FUNCTION <replaceable class="para
>      The return data type.
>      The output type may be specified as a base type, complex type,
>      <option>setof type</option>,
> -    or <option>opaque</option>.
> +    <option>opaque</option>, or the same as the type of an
> +    existing column.
>      The <option>setof</option>
>      modifier indicates that the function will return a set of items,
>      rather than a single item.
>
> ---------------------------(end of broadcast)---------------------------
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