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>>You can alias $0, similar to the argument variables. And, I confirmed

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>>that you cannot change the value, similar to the argument variables:
>
> Perhaps you shouldn't mark it isconst; then it would actually have some
> usefulness (you could use it directly as a temporary variable to hold
> the intended result).  I can't see much value in aliasing it if it's
> const, either.

OK; the only change in this version is "isconst = false;". Now you can
use $0 as a result placeholder if desired. E.g.:

create or replace function tmp(anyelement, anyelement) returns anyarray as '
declare
  v_ret alias for $0;
  v_el1 alias for $1;
  v_el2 alias for $2;
begin
  v_ret := ARRAY[v_el1, v_el2];
  return v_ret;
end;
' language 'plpgsql';

create table f(f1 text, f2 text, f3 int, f4 int);
insert into f values ('a','b',1,2);
insert into f values ('z','x',3,4);

select tmp(f1,f2) from f;
select tmp(f3,f4) from f;


Joe Conway
This commit is contained in:
Bruce Momjian 2003-07-26 23:58:23 +00:00
parent 9df03060e9
commit 1be17f1f26
1 changed files with 37 additions and 1 deletions
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38
src/pl/plpgsql/src/pl_comp.c
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@ -3,7 +3,7 @@
* procedural language
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/pl/plpgsql/src/pl_comp.c,v 1.60 2003/07/25 23:37:28 tgl Exp $
* $Header: /cvsroot/pgsql/src/pl/plpgsql/src/pl_comp.c,v 1.61 2003/07/26 23:58:23 momjian Exp $
*
* This software is copyrighted by Jan Wieck - Hamburg.
*
@ -361,6 +361,42 @@ do_compile(FunctionCallInfo fcinfo,
function->fn_rettyplen = typeStruct->typlen;
function->fn_rettypelem = typeStruct->typelem;
perm_fmgr_info(typeStruct->typinput, &(function->fn_retinput));
/*
* install $0 reference, but only for polymorphic
* return types
*/
if (procStruct->prorettype == ANYARRAYOID ||
procStruct->prorettype == ANYELEMENTOID)
{
char buf[32];
/* name for variable */
snprintf(buf, sizeof(buf), "$%d", 0);
/*
* Normal return values get a var node
*/
var = malloc(sizeof(PLpgSQL_var));
memset(var, 0, sizeof(PLpgSQL_var));
var->dtype = PLPGSQL_DTYPE_VAR;
var->refname = strdup(buf);
var->lineno = 0;
var->datatype = build_datatype(typeTup, -1);
var->isconst = false;
var->notnull = false;
var->default_val = NULL;
/* preset to NULL */
var->value = 0;
var->isnull = true;
var->freeval = false;
plpgsql_adddatum((PLpgSQL_datum *) var);
plpgsql_ns_additem(PLPGSQL_NSTYPE_VAR, var->varno,
var->refname);
}
}
ReleaseSysCache(typeTup);