add s:dedup, use it for user loaded extensions; begin using it in system extensions

FossilOrigin-Name: 0dbd909ec255a66290c0b0813addeebe61626aac2b43f62d9c00c6fa5a3aae61

interface/dedup.retro

@@ -5,4 +5,24 @@ String deduplication for RetroForth.
 (c) Arland Childers
 
 ~~~
+'init s:keep fll:create 's:dedup.data var-n
+
+{{
+  't1 var
+  't2 var
+---reveal---
+  :s:dedup.register (s-)
+    s:keep @s:dedup.data swap &fll:append/value sip ;
+  :s:dedup.defined? (s-f)
+    !t1 #0 !t2
+    @s:dedup.data [ @t1 s:eq? @t2 or !t2 ] fll:for-each @t2 ;
+  :s:dedup.find (s-s)
+    !t1 #0 !t2
+    @s:dedup.data [ dup @t1 s:eq? [ !t2 ] [ drop ] choose ]
+    fll:for-each @t2 ;
+  :s:dedup (s-s)
+    dup s:dedup.defined? [ s:dedup.find ] [ s:dedup.register ]
+    choose ;
+  :s:unique? (s-f) s:dedup.defined? ;
+}}
 ~~~

interface/ffi.retro

@@ -29,8 +29,9 @@
 :ffi:invoke (n-)
   #2 ffi:operation ;
 
-'interface/ffi.retro s:keep
+'interface/ffi.retro s:dedup
 dup 'ffi:operation d:lookup d:source store
+dup 'ffi:open d:lookup d:source store
 dup 'ffi:map-sym d:lookup d:source store
 dup 'ffi:invoke d:lookup d:source store
 drop

interface/filesystem.retro

@@ -167,7 +167,7 @@ once for each line in a file. This makes some things trivial. E.g., a simple
 ## d:source
 
 ~~~
-'interface/filesystem.retro s:keep
+'interface/filesystem.retro s:dedup
 dup 'file:spew d:lookup d:source store
 dup 'file:slurp d:lookup d:source store
 dup 'file:for-each-line d:lookup d:source store

interface/rng.retro

@@ -10,5 +10,5 @@ best approach on their host system.
     dup n:negative? [ drop 'Error:_device_(0010)_not_found s:put nl ] if;
     io:invoke ;
 
-'interface/rng.retro s:keep d:last d:source store
+'interface/rng.retro s:dedup d:last d:source store
 ~~~