Forget
This is an alternative to mark.
As a byproduct you get hide which hides a word from later
dictionary search.
~~~:d:exists? d:lookup n:zero? ;
'abort d:exists? [ 'example/Abort.forth include ] if
's:(evaluate) d:exists? [ 'example/EvaluateString.forth include ] if
~~~
~~~:d:size (-) #0 [ d:name drop #1 + ] d:for-each ;
:d:words.last (n-)
&Dictionary swap [ fetch dup d:name s:put sp d:link ] times drop ;
:EOC (-) 'EOC_(end-of-code) s:shout
d:size '%n_words_defined s:format s:put nl
#4 [ '%n_last_defined_words: s:format s:put sp ] sip d:words.last listen ;
~~~
~~~{{
'This 'Newer [ var ] bi@
:names-match? (a-f) d:name here s:eq? ;
:word-exists?continue (s-s) [ dup d:lookup ] assert ;
:d:newer-older (s-aa)_newer_older word-exists?continue
here s:copy d:last #0 !Newer [ dup names-match?
[ @Newer TRUE ] [ dup !Newer d:link fetch FALSE ] choose
] until (this_newer) swap d:link fetch (older) ;
:exist?continue (aa-aa) [ dup-pair [ n:-zero? ] bi@ and ] assert ;
---reveal---
:d:newer (s-a) d:newer-older drop ;
:d:hide (s-) d:newer-older exist?continue swap d:link store ;
}}
~~~
```:a ; :b ; :c ;
'b d:hide
'#5_d:words.last s:(evaluate)
```
Forget
~~~:d:forget.a (a-) dup n:-zero? [ dup !Heap d:link fetch !Dictionary ]
[ drop 'tried_to_d:forget_a_word_that_doesn't_exist. s:shout ] choose ;
:d:forget (s-) d:lookup d:forget.a ;
:f:reset (-|float:?-) f:depth [ f:drop ] times ;
:reset.nf (?-|float:?-) reset f:reset ;
:d:wipe (-) reset.nf '---wipe--- d:newer d:forget.a ;
~~~
:---wipe--- ;
:a ; :b ; :c ; nl
'#5_d:words.last s:(evaluate)
d:wipe nl
'#5_d:words.last s:(evaluate) nl