Lexical Scope
RETRO has a single dictionary, but does provide a means of using
lexical scope to keep this dictionary clean.
Example
```
{{
'A var
:++A &A v:inc ;
---reveal---
:B ++A ++A @A n:put nl ;
}}
```
In this example, the lexical namespace is created with {{. A
variable (A) and word (++A) are defined. Then a marker is
set with ---reveal---. Another word (B) is defined, and the
lexical area is closed with }}.
The headers between {{ and ---reveal--- are then hidden from
the dictionary, leaving only the headers between ---reveal---
and }} exposed.
Notes
This only affects word visibility within the scoped area. As an
example:
```
:a #1 ;
{{
:a #2 ;
---reveal---
:b 'a s:evaluate n:put ;
}}
```
In this, after }} closes the area, the :a #2 ; is hidden and
the s:evaluate will find the :a #1 ; when b is run.