Sigil
Pointers are returned by the & sigil.
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.