remembered to update

201/week2/dfs.hoon

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+:: Hoon 201 - Week 2
+:: ~bannum-magtus || s@p7.co.nz
+::
+:: i could not figure out how to
+:: cast the output of a wet gate
+:: to a list of the same type :(
+::
+:-  %say
+|=  [* [t=(tree @) x=@ ~] *]
+:-  %noun
+^-  [? (list @)]
+=<  
+:-  (dfs-search t x)  (dfs t)
+|%
+++  dfs
+  |=  t=(tree @)
+  ^-  (list @)
+  ?~  t
+    ~
+  %+  weld
+    (dfs l.t)
+  %+  weld
+    (dfs r.t)
+  [n.t ~]
+++  dfs-search
+  |=  [t=(tree @) x=@]
+  ^-  ?
+  ?~  t
+    %.n
+  ?|  (dfs-search l.t x)
+      (dfs-search r.t x)
+      =(n.t x)
+  ==
+  :: i assume ?| will stop as
+  :: soon as it sees a true,
+  :: otherwise below is better
+  ::
+  ::?:  (dfs-search l.t x)  %.y
+  ::?:  (dfs-search r.t x)  %.y
+  ::=(x n.t)
+--
+