# Proposal: [307] Fix stack comments for N>R and NR>

This page is dedicated to discussing this specific proposal

## ContributeContributions

## LeonWagner [307] Fix stack comments for N>R and NR>Proposal2023-09-13 12:09:40

## Author:

Leon Wagner

## Change Log

2023-09-13 Initial proposal

## Problem:

The stack comments for N>R and NR> don't make it clear that *n* items are moved between the data and return stacks.

## Solution:

The stack comments should more clearly indicate that *n* data stack items are moved to or from the return stack.

## Proposal:

Change the stack comments for 15.6.2.1908 N>R to * ( n*x +n -- ) ( R: -- n*x +n )* and 15.6.2.1940 NR> to

`( -- n*x +n ) ( R: n*x +n -- )`

## ruv [310] Why do we use +n and not u in the stack diagram for n>r and nr>Request for clarification2023-09-23 01:06:43

A citation from the Discussion section (in r1079):

On the data stack

`x_n ... x_1 +n`

because that is the way we usually specify a numbered number of cells (even for`+n=0`

). See, e.g.,`get-order`

.

Well, in `get-order`

*n* (the signed number data type) is probably incorrectly used after `set-order`

, where *n* can be `-1`

.

But in other words:
`pick`

,
`roll`

,
`cs-pick`

,
`cs-roll`

,
— the unsigned number data type (identified by *u*) is used to indicate the number of items.

So the question is: why is `+n`

used in the stack diagrams for `n>r`

and `nr>`

instead of `u`

?