Hoon101/201/week2/dfs.hoon

:: 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)
--