retroforth/example/namespaces.retro

This is a little set of words to create an array with all of the
currently defined namespaces in a RETRO image.

Three words will be exposed.

    Namespace              Array, holds the namespace strings
    namespaces:identify    Rebuild the array
    namespaces:put         Display the namespaces

~~~
'Namespaces d:create #513 allot

{{
  :has-namespace? dup $: s:contains/char? ;
  :get-namespace  $: s:split nip ;
  :known?  dup &Namespaces a:contains/string? ;
  :add     s:keep buffer:add &Namespaces v:inc ;
  :process get-namespace known? &drop &add choose ;
---reveal---
  :namespaces:identify
    [ &Namespaces buffer:set #0 buffer:add
      [ d:name has-namespace? &process &drop choose ] d:for-each
    ] buffer:preserve ;
  :namespaces:put &Namespaces [ s:put sp ] a:for-each ;
}}
~~~

A quick test:

```
namespaces:identify
namespaces:put nl
```