Function make_datum_param

src/pl/plpgsql/src/pl_comp.c:1361–1392

* Helper for columnref parsing: build a Param referencing a plpgsql datum, * and make sure that that datum is listed in the expression's paramnos. */

 * and make sure that that datum is listed in the expression's paramnos.
 */
static Node *
make_datum_param(PLpgSQL_expr *expr, int dno, int location)
{
	PLpgSQL_execstate *estate;
	PLpgSQL_datum *datum;
	Param	   *param;
	MemoryContext oldcontext;

	/* see comment in resolve_column_ref */
	estate = expr->func->cur_estate;
	Assert(dno >= 0 && dno < estate->ndatums);
	datum = estate->datums[dno];

	/*
	 * Bitmapset must be allocated in function's permanent memory context
	 */
	oldcontext = MemoryContextSwitchTo(expr->func->fn_cxt);
	expr->paramnos = bms_add_member(expr->paramnos, dno);
	MemoryContextSwitchTo(oldcontext);

	param = makeNode(Param);
	param->paramkind = PARAM_EXTERN;
	param->paramid = dno + 1;
	plpgsql_exec_get_datum_type_info(estate,
									 datum,
									 &param->paramtype,
									 &param->paramtypmod,
									 &param->paramcollid);
	param->location = location;

	return (Node *) param;
}


/* ----------