Re: Doc patch--clarifying $1 in PL/PgSQL - Mailing list pgsql-patches

Tom Lane wrote:

> David Fetter <david@fetter.org> writes:
>> On Mon, Dec 22, 2003 at 05:50:12PM -0500, Tom Lane wrote:
>>> David Fetter <david@fetter.org> writes:
>> +      Note that it is not possible to assign function arguments during
>> +      a <literal>DECLARE</> block.
>>>
>>> Seems to me this is a bug that should be fixed, not documented.
>
>> I got the impression from Jan Wieck that it wasn't fixable, or at
>> least not without a major rewrite of the plpgsql engine.  I'm sure
>> somebody will correct me if I got a mistaken impression, though :)
>
> Not that hard ... just requires replacing some special-purpose code with
> general-purpose code ...

Does that code cause the variables value to change from function call to
function call (what most users would expect if they give it a default
value based on a call argument), or will remember the value from the
first function call for the lifetime of the backend?


Jan

>
>             regards, tom lane
>
>
> *** src/pl/plpgsql/src/gram.y.orig    Sat Nov 29 14:52:12 2003
> --- src/pl/plpgsql/src/gram.y    Mon Dec 22 18:50:35 2003
> ***************
> *** 628,679 ****
>                       { $$ = NULL; }
>                   | decl_defkey
>                       {
> !                         int                tok;
> !                         int                lno;
> !                         PLpgSQL_dstring ds;
> !                         PLpgSQL_expr    *expr;
> !
> !                         lno = plpgsql_scanner_lineno();
> !                         expr = malloc(sizeof(PLpgSQL_expr));
> !                         plpgsql_dstring_init(&ds);
> !                         plpgsql_dstring_append(&ds, "SELECT ");
> !
> !                         expr->dtype   = PLPGSQL_DTYPE_EXPR;
> !                         expr->plan      = NULL;
> !                         expr->nparams = 0;
> !
> !                         tok = yylex();
> !                         switch (tok)
> !                         {
> !                             case 0:
> !                                 yyerror("unexpected end of function");
> !                             case K_NULL:
> !                                 if (yylex() != ';')
> !                                     yyerror("expected \";\" after \"NULL\"");
> !
> !                                 free(expr);
> !                                 plpgsql_dstring_free(&ds);
> !
> !                                 $$ = NULL;
> !                                 break;
> !
> !                             default:
> !                                 plpgsql_dstring_append(&ds, yytext);
> !                                 while ((tok = yylex()) != ';')
> !                                 {
> !                                     if (tok == 0)
> !                                         yyerror("unterminated default value");
> !
> !                                     if (plpgsql_SpaceScanned)
> !                                         plpgsql_dstring_append(&ds, " ");
> !                                     plpgsql_dstring_append(&ds, yytext);
> !                                 }
> !                                 expr->query = strdup(plpgsql_dstring_get(&ds));
> !                                 plpgsql_dstring_free(&ds);
> !
> !                                 $$ = expr;
> !                                 break;
> !                         }
>                       }
>                   ;
>
> --- 628,636 ----
>                       { $$ = NULL; }
>                   | decl_defkey
>                       {
> !                         plpgsql_ns_setlocal(false);
> !                         $$ = plpgsql_read_expression(';', ";");
> !                         plpgsql_ns_setlocal(true);
>                       }
>                   ;
>
>
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