retroforth/book/Programming-Techniques-Working-With-Pointers

# Working With Pointers

## Prefix

Pointers are returned by the `&` prefix.

## Examples

```
'Base var
&Base fetch
#10 &Base store

#10 &n:inc call
```

## Notes

The use of `&` to get a pointer to a data structure (with a
word class of `class:data`) is not required. I like to use it
anyway as it makes my intent a little clearer.

Pointers are useful with combinators. Consider:

```
:abs dup n:negative? [ n:negate ] if ;
```

Since the target quote body is a single word, it is more
efficient to use a pointer instead:

```
:abs dup n:negative? &n:negate if ;
```

The advantages are speed (saves a level of call/return by
avoiding the quotation) and size (for the same reason).
This may be less readable though, so consider the balance
of performance to readability when using this approach.