pl_exec.c

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		}
	}

	return PLPGSQL_RC_OK;
}


/* ----------
 * exec_stmt_fori			Iterate an integer variable
 *					from a lower to an upper value
 *					incrementing or decrementing by the BY value
 * ----------
 */
static int
exec_stmt_fori(PLpgSQL_execstate *estate, PLpgSQL_stmt_fori *stmt)
{
	PLpgSQL_var *var;
	Datum		value;
	bool		isnull;
	Oid			valtype;
	int32		loop_value;
	int32		end_value;
	int32		step_value;
	bool		found = false;
	int			rc = PLPGSQL_RC_OK;

	var = (PLpgSQL_var *) (estate->datums[stmt->var->varno]);

	/*
	 * Get the value of the lower bound
	 */
	value = exec_eval_expr(estate, stmt->lower, &isnull, &valtype);
	value = exec_cast_value(value, valtype, var->datatype->typoid,
							&(var->datatype->typinput),
							var->datatype->typioparam,
							var->datatype->atttypmod, isnull);
	if (isnull)
		ereport(ERROR,
				(errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
				 errmsg("lower bound of FOR loop cannot be NULL")));
	loop_value = DatumGetInt32(value);
	exec_eval_cleanup(estate);

	/*
	 * Get the value of the upper bound
	 */
	value = exec_eval_expr(estate, stmt->upper, &isnull, &valtype);
	value = exec_cast_value(value, valtype, var->datatype->typoid,
							&(var->datatype->typinput),
							var->datatype->typioparam,
							var->datatype->atttypmod, isnull);
	if (isnull)
		ereport(ERROR,
				(errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
				 errmsg("upper bound of FOR loop cannot be NULL")));
	end_value = DatumGetInt32(value);
	exec_eval_cleanup(estate);

	/*
	 * Get the step value
	 */
	if (stmt->step)
	{
		value = exec_eval_expr(estate, stmt->step, &isnull, &valtype);
		value = exec_cast_value(value, valtype, var->datatype->typoid,
								&(var->datatype->typinput),
								var->datatype->typioparam,
								var->datatype->atttypmod, isnull);
		if (isnull)
			ereport(ERROR,
					(errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
					 errmsg("BY value of FOR loop cannot be NULL")));
		step_value = DatumGetInt32(value);
		exec_eval_cleanup(estate);
		if (step_value <= 0)
			ereport(ERROR,
					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
				  errmsg("BY value of FOR loop must be greater than zero")));
	}
	else
		step_value = 1;

	/*
	 * Now do the loop
	 */
	for (;;)
	{
		/*
		 * Check against upper bound
		 */
		if (stmt->reverse)
		{
			if (loop_value < end_value)
				break;
		}
		else
		{
			if (loop_value > end_value)
				break;
		}

		found = true;			/* looped at least once */

		/*
		 * Assign current value to loop var
		 */
		var->value = Int32GetDatum(loop_value);
		var->isnull = false;

		/*
		 * Execute the statements
		 */
		rc = exec_stmts(estate, stmt->body);

		if (rc == PLPGSQL_RC_RETURN)
			break;				/* return from function */
		else if (rc == PLPGSQL_RC_EXIT)
		{
			if (estate->exitlabel == NULL)
				/* unlabelled exit, finish the current loop */
				rc = PLPGSQL_RC_OK;
			else if (stmt->label != NULL &&
					 strcmp(stmt->label, estate->exitlabel) == 0)
			{
				/* labelled exit, matches the current stmt's label */
				estate->exitlabel = NULL;
				rc = PLPGSQL_RC_OK;
			}

			/*
			 * otherwise, this is a labelled exit that does not match the
			 * current statement's label, if any: return RC_EXIT so that the
			 * EXIT continues to propagate up the stack.
			 */
			break;
		}
		else if (rc == PLPGSQL_RC_CONTINUE)
		{
			if (estate->exitlabel == NULL)
				/* unlabelled continue, so re-run the current loop */
				rc = PLPGSQL_RC_OK;
			else if (stmt->label != NULL &&
					 strcmp(stmt->label, estate->exitlabel) == 0)
			{
				/* label matches named continue, so re-run loop */
				estate->exitlabel = NULL;
				rc = PLPGSQL_RC_OK;
			}
			else
			{
				/*
				 * otherwise, this is a named continue that does not match the
				 * current statement's label, if any: return RC_CONTINUE so
				 * that the CONTINUE will propagate up the stack.
				 */
				break;
			}
		}

		/*
		 * Increase/decrease loop value, unless it would overflow, in which
		 * case exit the loop.
		 */
		if (stmt->reverse)
		{
			if ((int32) (loop_value - step_value) > loop_value)
				break;
			loop_value -= step_value;
		}
		else
		{
			if ((int32) (loop_value + step_value) < loop_value)
				break;
			loop_value += step_value;
		}
	}

	/*
	 * Set the FOUND variable to indicate the result of executing the loop
	 * (namely, whether we looped one or more times). This must be set here so
	 * that it does not interfere with the value of the FOUND variable inside
	 * the loop processing itself.
	 */
	exec_set_found(estate, found);

	return rc;
}


/* ----------
 * exec_stmt_fors			Execute a query, assign each
 *					tuple to a record or row and
 *					execute a group of statements
 *					for it.
 * ----------
 */
static int
exec_stmt_fors(PLpgSQL_execstate *estate, PLpgSQL_stmt_fors *stmt)
{
	PLpgSQL_rec *rec = NULL;
	PLpgSQL_row *row = NULL;
	SPITupleTable *tuptab;
	Portal		portal;
	bool		found = false;
	int			rc = PLPGSQL_RC_OK;
	int			i;
	int			n;

	/*
	 * Determine if we assign to a record or a row
	 */
	if (stmt->rec != NULL)
		rec = (PLpgSQL_rec *) (estate->datums[stmt->rec->recno]);
	else if (stmt->row != NULL)
		row = (PLpgSQL_row *) (estate->datums[stmt->row->rowno]);
	else
		elog(ERROR, "unsupported target");

	/*
	 * Open the implicit cursor for the statement and fetch the initial 10
	 * rows.
	 */
	exec_run_select(estate, stmt->query, 0, &portal);

	SPI_cursor_fetch(portal, true, 10);
	tuptab = SPI_tuptable;
	n = SPI_processed;

	/*
	 * If the query didn't return any rows, set the target to NULL and return
	 * with FOUND = false.
	 */
	if (n == 0)
		exec_move_row(estate, rec, row, NULL, tuptab->tupdesc);
	else
		found = true;			/* processed at least one tuple */

	/*
	 * Now do the loop
	 */
	while (n > 0)
	{
		for (i = 0; i < n; i++)
		{
			/*
			 * Assign the tuple to the target
			 */
			exec_move_row(estate, rec, row, tuptab->vals[i], tuptab->tupdesc);

			/*
			 * Execute the statements
			 */
			rc = exec_stmts(estate, stmt->body);
			if (rc != PLPGSQL_RC_OK)
			{
				if (rc == PLPGSQL_RC_EXIT)
				{
					if (estate->exitlabel == NULL)
						/* unlabelled exit, finish the current loop */
						rc = PLPGSQL_RC_OK;
					else if (stmt->label != NULL &&
							 strcmp(stmt->label, estate->exitlabel) == 0)
					{
						/* labelled exit, matches the current stmt's label */
						estate->exitlabel = NULL;
						rc = PLPGSQL_RC_OK;
					}

					/*
					 * otherwise, we processed a labelled exit that does not
					 * match the current statement's label, if any: return
					 * RC_EXIT so that the EXIT continues to recurse upward.
					 */
				}
				else if (rc == PLPGSQL_RC_CONTINUE)
				{
					if (estate->exitlabel == NULL)
					{
						/* anonymous continue, so re-run the current loop */
						rc = PLPGSQL_RC_OK;
						continue;
					}
					else if (stmt->label != NULL &&
							 strcmp(stmt->label, estate->exitlabel) == 0)
					{
						/* label matches named continue, so re-run loop */
						rc = PLPGSQL_RC_OK;
						estate->exitlabel = NULL;
						continue;
					}

					/*
					 * otherwise, we processed a named continue that does not
					 * match the current statement's label, if any: return
					 * RC_CONTINUE so that the CONTINUE will propagate up the
					 * stack.
					 */
				}

				/*
				 * We're aborting the loop, so cleanup and set FOUND. (This
				 * code should match the code after the loop.)
				 */
				SPI_freetuptable(tuptab);
				SPI_cursor_close(portal);
				exec_set_found(estate, found);

				return rc;
			}
		}

		SPI_freetuptable(tuptab);

		/*
		 * Fetch the next 50 tuples
		 */
		SPI_cursor_fetch(portal, true, 50);
		n = SPI_processed;
		tuptab = SPI_tuptable;
	}

	/*
	 * Release last group of tuples
	 */
	SPI_freetuptable(tuptab);

	/*
	 * Close the implicit cursor
	 */
	SPI_cursor_close(portal);

	/*
	 * Set the FOUND variable to indicate the result of executing the loop
	 * (namely, whether we looped one or more times). This must be set here so
	 * that it does not interfere with the value of the FOUND variable inside
	 * the loop processing itself.
	 */
	exec_set_found(estate, found);

	return rc;
}


/* ----------
 * exec_stmt_exit			Implements EXIT and CONTINUE
 *
 * This begins the process of exiting / restarting a loop.
 * ----------
 */
static int
exec_stmt_exit(PLpgSQL_execstate *estate, PLpgSQL_stmt_exit *stmt)
{
	/*
	 * If the exit / continue has a condition, evaluate it
	 */
	if (stmt->cond != NULL)
	{
		bool		value;
		bool		isnull;

		value = exec_eval_boolean(estate, stmt->cond, &isnull);
		exec_eval_cleanup(estate);
		if (isnull || value == false)
			return PLPGSQL_RC_OK;
	}

	estate->exitlabel = stmt->label;
	if (stmt->is_exit)
		return PLPGSQL_RC_EXIT;
	else
		return PLPGSQL_RC_CONTINUE;
}


/* ----------
 * exec_stmt_return			Evaluate an expression and start
 *					returning from the function.
 * ----------
 */
static int
exec_stmt_return(PLpgSQL_execstate *estate, PLpgSQL_stmt_return *stmt)
{
	/*
	 * If processing a set-returning PL/PgSQL function, the final RETURN
	 * indicates that the function is finished producing tuples.  The rest of
	 * the work will be done at the top level.
	 */
	if (estate->retisset)
		return PLPGSQL_RC_RETURN;

	/* initialize for null result (possibly a tuple) */
	estate->retval = (Datum) 0;
	estate->rettupdesc = NULL;
	estate->retisnull = true;

	if (stmt->retvarno >= 0)
	{
		PLpgSQL_datum *retvar = estate->datums[stmt->retvarno];

		switch (retvar->dtype)
		{
			case PLPGSQL_DTYPE_VAR:
				{
					PLpgSQL_var *var = (PLpgSQL_var *) retvar;

					estate->retval = var->value;
					estate->retisnull = var->isnull;
					estate->rettype = var->datatype->typoid;
				}
				break;

			case PLPGSQL_DTYPE_REC:
				{
					PLpgSQL_rec *rec = (PLpgSQL_rec *) retvar;

					if (HeapTupleIsValid(rec->tup))
					{
						estate->retval = (Datum) rec->tup;
						estate->rettupdesc = rec->tupdesc;
						estate->retisnull = false;
					}
				}
				break;

			case PLPGSQL_DTYPE_ROW:
				{
					PLpgSQL_row *row = (PLpgSQL_row *) retvar;

					Assert(row->rowtupdesc);
					estate->retval = (Datum) make_tuple_from_row(estate, row,
															row->rowtupdesc);
					if (estate->retval == (Datum) NULL) /* should not happen */
						elog(ERROR, "row not compatible with its own tupdesc");
					estate->rettupdesc = row->rowtupdesc;
					estate->retisnull = false;
				}
				break;

			default:
				elog(ERROR, "unrecognized dtype: %d", retvar->dtype);
		}

		return PLPGSQL_RC_RETURN;
	}

	if (stmt->expr != NULL)
	{
		if (estate->retistuple)
		{
			exec_run_select(estate, stmt->expr, 1, NULL);
			if (estate->eval_processed > 0)
			{
				estate->retval = (Datum) estate->eval_tuptable->vals[0];
				estate->rettupdesc = estate->eval_tuptable->tupdesc;
				estate->retisnull = false;
			}
		}
		else
		{
			/* Normal case for scalar results */
			estate->retval = exec_eval_expr(estate, stmt->expr,
											&(estate->retisnull),
											&(estate->rettype));
		}

		return PLPGSQL_RC_RETURN;
	}

	/*
	 * Special hack for function returning VOID: instead of NULL, return a
	 * non-null VOID value.  This is of dubious importance but is kept for
	 * backwards compatibility.  Note that the only other way to get here is
	 * to have written "RETURN NULL" in a function returning tuple.
	 */
	if (estate->fn_rettype == VOIDOID)
	{
		estate->retval = (Datum) 0;
		estate->retisnull = false;
		estate->rettype = VOIDOID;
	}

	return PLPGSQL_RC_RETURN;
}

/* ----------
 * exec_stmt_return_next		Evaluate an expression and add it to the
 *								list of tuples returned by the current
 *								SRF.
 * ----------
 */
static int
exec_stmt_return_next(PLpgSQL_execstate *estate,
					  PLpgSQL_stmt_return_next *stmt)
{
	TupleDesc	tupdesc;
	int			natts;
	HeapTuple	tuple;
	bool		free_tuple = false;

	if (!estate->retisset)
		ereport(ERROR,
				(errcode(ERRCODE_SYNTAX_ERROR),
				 errmsg("cannot use RETURN NEXT in a non-SETOF function")));

	if (estate->tuple_store == NULL)