This is a quick little thing to generate some statistics
from the RETRO image and VM, along with some introspection
to identify prefix handlers and word classes.

# Memory Use

First, memory. This is easy due to the defined constants
and queries provided by RETRO.

~~~
nl 'Memory: s:put nl nl

  EOM '__Total_memory:_%n\n s:format s:put
  FREE '__Free_memory:__%n\n s:format s:put
  here '__Used_memory:__%n\n s:format s:put
~~~

# Dictionary

Next, some statistics on the dictionary. The header sizing
would need to be adjusted if you add or remove fields from
them.

The header contains fields for:

  link to prior
  address
  pointer to class handler
  null terminated string with the name

So the size is 4 cells (the three fields and null terminator)
plus the length of the name.

~~~
nl 'Dictionary: s:put nl nl

  #0 [ d:name s:length #4 + + ] d:for-each
  '__Headers_consume_%n\n s:format s:put

  #0 [ d:name s:length + n:inc ] d:for-each
  '__Names_consume_%n\n s:format s:put
~~~

Determine the number of words in the dictionary.

~~~
  #0 [ drop n:inc ] d:for-each
  '__%n_names_defined\n s:format s:put
~~~

Determine the average length of a word name.

~~~
  #0 [ d:name s:length + ] d:for-each
  #0 [ drop n:inc ] d:for-each
  / '__Average_name_length:_%n\n s:format s:put
~~~

And without the prefixes...

~~~
  #0 #0 [ d:name dup $: s:index-of n:inc + s:length + [ n:inc ] dip ] d:for-each swap /
  '__Average_name_without_namespace:_%n\n s:format s:put
~~~

Longest name are...

~~~
  #0 [ d:name s:length n:max ] d:for-each
  '__Longest_names_are_%n_characters\n s:format s:put
~~~

# Identify Classes

Word classes are conventionally named as:

    class:<name>

This prints the names of words matching them. It also demonstrates
constructing an array of the names, which can be adapted for other
purposes.

~~~
nl 'Classes: s:put nl nl

:identify-classes (-a)
  here #0 ,
  [ d:name dup 'class: s:contains-string?
    &, &drop choose ] d:for-each
  here over - n:dec over store ;

sp sp identify-classes [ s:put sp ] a:for-each nl
~~~

# Identify Prefixes

Prefixes are named as:

    prefix:<character>

Unlike classes, this is not merely a convention, but an actual
requirement.

The process for obtaining an array of them and printing it is
the same as with the class handlers.

~~~
nl 'Prefixes: s:put nl nl

:identify-prefixes (-a)
  here #0 ,
  [ d:name dup 'prefix: s:contains-string?
    &, &drop choose ] d:for-each
  here over - n:dec over store ;

sp sp identify-prefixes [ s:put sp ] a:for-each nl

nl
~~~