add d:lookup-xt to standard image

FossilOrigin-Name: 93028838c88b5a721c03520ed51d80e795ec5006c6dce4bf204f081e0aa1e321

Words.txt

@@ -222,6 +222,7 @@ compile:
   d:last<xt>
   d:link
   d:lookup
+  d:lookup-xt
   d:name
   d:xt
 

doc/Glossary.txt

@@ -1049,6 +1049,16 @@ This returns zero if the word is not found.
 
 -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
 
+d:lookup-xt
+
+  a-d
+
+Lookup the specified address in the dictionary
+and return a pointer to its dictionary header.
+This returns zero if the word is not found.
+
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
+
 d:name
 
   d-s

example/Disassembler.forth

@@ -80,21 +80,6 @@ long as instruction bundle strings (8 characters).
   s:length #30 swap - #0 n:max [ sp ] times ;
 ~~~
 
-As I was working I decided I wanted a way to see the names that went
-along with calls, jumps, etc. So I wrote a quick word to find the DT
-that goes along with an XT. If none is found, it returns zero.
-
-~~~
-{{
-  'Matching var
----reveal---
-  :d:lookup-xt (a-d)
-    #0 !Matching
-    [ [ d:xt fetch over eq? ] sip swap [ !Matching ] [ drop ] choose ] d:for-each drop
-    @Matching ;
-}}
-~~~
-
 I split out each type (instruction, reference/raw, and data) into a
 separate handler.
 

literate/RetroForth.md

@@ -948,6 +948,15 @@ dictionary in a very clean manner.
  dup-pair [ [ swap call ] dip ] dip again ] call drop ;
 ~~~
 
+Using `d:for-each`, I implement a means of looking up a dictionary
+header by the `d:xt` field.
+
+~~~
+:d:lookup-xt (a-d)
+ #0 swap [ dup-pair d:xt fetch eq?
+           [ swap [ nip ] dip ] [ drop ] choose ] d:for-each drop ;
+~~~
+
 Use `s:with-format` to construct a string from multiple items. This
 can be illustrated with: