=>  |%
    ::
    ++  system
      $:  rec/(map @ud theory)
          say/theory
      ==
    ++  library

    ::
    ++  theory
      $@  $?  $void
              $path
              $noun
              $hoon
              $wall
              $text
              $tape
              $cord
              $null
              $term
              $type
              $tank
          ==
      $%  {$list item/theory}
          {$pole item/theory}
          {$set item/theory}
          {$map key/theory value/theory}
          {$soft type/type data/theory}
          {$tuple items/(list theory)}
          {$label name/term data/theory}
          {$tree item/theory}
          {$help writ/writ theory/theory}
          {$gate from/theory to/theory}
          ::  {$core library/}
          {$unit item/theory}
          {$atom aura/aura}
          {$choice cases/(list theory)}
          {$branch atom/theory cell/theory}
          {$bridge double/theory single/theory}
          {$switch cases/(list {stem/theory bulb/theory})}
          {$constant aura/aura value/@}
          {$pair p/theory q/theory}
          {$trel p/theory q/theory r/theory}
          {$qual p/theory q/theory r/theory s/theory}
          {$quil p/theory q/theory r/theory s/theory t/theory}
      --
|%
++  py



++  us                                                  ::  prettyprinter
  =>  |%
      ++  cape  {p/(map @ud wine) q/wine}               ::
      ++  wine                                          ::
                $@  $?  $noun                           ::
                        $path                           ::
                        $type                           ::
                        $void                           ::
                        $wall                           ::
                        $wool                           ::
                        $yarn                           ::
                    ==                                  ::
                $%  {$mato p/term}                      ::
                    {$core p/(list @ta) q/wine}         ::
                    {$face p/term q/wine}               ::
                    {$list p/term q/wine}               ::
                    {$pear p/term q/@}                  ::
                    {$bcwt p/(list wine)}               ::
                    {$plot p/(list wine)}               ::
                    {$stop p/@ud}                       ::
                    {$tree p/term q/wine}               ::
                    {$unit p/term q/wine}               ::
                ==                                      ::
      --
  |_  sut/type
  ++  dash
      |=  {mil/tape lim/char}  ^-  tape
      :-  lim
      |-  ^-  tape
      ?~  mil  [lim ~]
      ?:  =(lim i.mil)  ['\\' i.mil $(mil t.mil)]
      ?:  =('\\' i.mil)  ['\\' i.mil $(mil t.mil)]
      ?:  (lte ' ' i.mil)  [i.mil $(mil t.mil)]
      ['\\' ~(x ne (rsh 2 1 i.mil)) ~(x ne (end 2 1 i.mil)) $(mil t.mil)]
  ::
  ++  deal  |=(lum/* (dish dole lum))
  ++  dial
    |=  ham/cape
    =+  gid=*(set @ud)
    =<  `tank`-:$
    |%
    ++  many
      |=  haz/(list wine)
      ^-  {(list tank) (set @ud)}
      ?~  haz  [~ gid]
      =^  mor  gid  $(haz t.haz)
      =^  dis  gid  ^$(q.ham i.haz)
      [[dis mor] gid]
    ::
    ++  $
      ^-  {tank (set @ud)}
      ?-    q.ham
          $noun      :_(gid [%leaf '*' ~])
          $path      :_(gid [%leaf '/' ~])
          $type      :_(gid [%leaf '#' 't' ~])
          $void      :_(gid [%leaf '#' '!' ~])
          $wool      :_(gid [%leaf '*' '"' '"' ~])
          $wall      :_(gid [%leaf '*' '\'' '\'' ~])
          $yarn      :_(gid [%leaf '"' '"' ~])
          {$mato *}  :_(gid [%leaf '@' (trip p.q.ham)])
          {$core *}
        =^  cox  gid  $(q.ham q.q.ham)
        :_  gid
        :+  %rose
          [[' ' ~] ['<' ~] ['>' ~]]
        |-  ^-  (list tank)
        ?~  p.q.ham  [cox ~]
        [[%leaf (rip 3 i.p.q.ham)] $(p.q.ham t.p.q.ham)]
      ::
          {$face *}
        =^  cox  gid  $(q.ham q.q.ham)
        :_(gid [%palm [['/' ~] ~ ~ ~] [%leaf (trip p.q.ham)] cox ~])
      ::
          {$list *}
        =^  cox  gid  $(q.ham q.q.ham)
        :_(gid [%rose [" " (weld (trip p.q.ham) "(") ")"] cox ~])
      ::
          {$bcwt *}
        =^  coz  gid  (many p.q.ham)
        :_(gid [%rose [[' ' ~] ['?' '(' ~] [')' ~]] coz])
      ::
          {$plot *}
        =^  coz  gid  (many p.q.ham)
        :_(gid [%rose [[' ' ~] ['{' ~] ['}' ~]] coz])
      ::
          {$pear *}
        :_(gid [%leaf '$' ~(rend co [%$ p.q.ham q.q.ham])])
      ::
          {$stop *}
        =+  num=~(rend co [%$ %ud p.q.ham])
        ?:  (~(has in gid) p.q.ham)
          :_(gid [%leaf '#' num])
        =^  cox  gid
            %=  $
              gid    (~(put in gid) p.q.ham)
              q.ham  (~(got by p.ham) p.q.ham)
            ==
        :_(gid [%palm [['.' ~] ~ ~ ~] [%leaf ['^' '#' num]] cox ~])
      ::
          {$tree *}
        =^  cox  gid  $(q.ham q.q.ham)
        :_(gid [%rose [" " (weld (trip p.q.ham) "(") ")"] cox ~])
      ::
          {$unit *}
        =^  cox  gid  $(q.ham q.q.ham)
        :_(gid [%rose [" " (weld (trip p.q.ham) "(") ")"] cox ~])
      ==
    --
  ::
  ++  dish
    |=  {ham/cape lum/*}  ^-  tank
    ~|  [%dish-h ?@(q.ham q.ham -.q.ham)]
    ~|  [%lump lum]
    ~|  [%ham ham]
    %-  need
    =|  gil/(set {@ud *})
    |-  ^-  (unit tank)
    ?-    q.ham
        $noun
      %=    $
          q.ham
        ?:  ?=(@ lum)
          [%mato %$]
        :-  %plot
        |-  ^-  (list wine)
        [%noun ?:(?=(@ +.lum) [[%mato %$] ~] $(lum +.lum))]
      ==
    ::
        $path
      :-  ~
      :+  %rose
        [['/' ~] ['/' ~] ~]
      |-  ^-  (list tank)
      ?~  lum  ~
      ?@  lum  !!
      ?>  ?=(@ -.lum)
      [[%leaf (rip 3 -.lum)] $(lum +.lum)]
    ::
        $type
      =+  tyr=|.((dial dole))
      =+  vol=tyr(sut lum)
      =+  cis=((hard tank) .*(vol -:vol))
      :^  ~   %palm
        [~ ~ ~ ~]
      [[%leaf '#' 't' '/' ~] cis ~]
    ::
        $wall
      :-  ~
      :+  %rose
        [[' ' ~] ['<' '|' ~] ['|' '>' ~]]
      |-  ^-  (list tank)
      ?~  lum  ~
      ?@  lum  !!
      [[%leaf (trip ((hard @) -.lum))] $(lum +.lum)]
    ::
        $wool
      :-  ~
      :+  %rose
        [[' ' ~] ['<' '<' ~] ['>' '>' ~]]
      |-  ^-  (list tank)
      ?~  lum  ~
      ?@  lum  !!
      [(need ^$(q.ham %yarn, lum -.lum)) $(lum +.lum)]
    ::
        $yarn
      [~ %leaf (dash (tape lum) '"')]
    ::
        $void
      ~
    ::
        {$mato *}
      ?.  ?=(@ lum)
        ~
      :+  ~
        %leaf
      ?+    (rash p.q.ham ;~(sfix (cook crip (star low)) (star hig)))
          ~(rend co [%$ p.q.ham lum])
        $$    ~(rend co [%$ %ud lum])
        $t    (dash (rip 3 lum) '\'')
        $tas  ['%' ?.(=(0 lum) (rip 3 lum) ['$' ~])]
      ==
    ::
        {$core *}
      ::  XX  needs rethinking for core metal
      ::  ?.  ?=(^ lum)  ~
      ::  =>  .(lum `*`lum)
      ::  =-  ?~(tok ~ [~ %rose [[' ' ~] ['<' ~] ['>' ~]] u.tok])
      ::  ^=  tok
      ::  |-  ^-  (unit (list tank))
      ::  ?~  p.q.ham
      ::    =+  den=^$(q.ham q.q.ham)
      ::    ?~(den ~ [~ u.den ~])
      ::  =+  mur=$(p.q.ham t.p.q.ham, lum +.lum)
      ::  ?~(mur ~ [~ [[%leaf (rip 3 i.p.q.ham)] u.mur]])
      [~ (dial ham)]
    ::
        {$face *}
      =+  wal=$(q.ham q.q.ham)
      ?~  wal
        ~
      [~ %palm [['=' ~] ~ ~ ~] [%leaf (trip p.q.ham)] u.wal ~]
    ::
        {$list *}
      ?:  =(~ lum)
        [~ %leaf '~' ~]
      =-  ?~  tok
            ~
          [~ %rose [[' ' ~] ['~' '[' ~] [']' ~]] u.tok]
      ^=  tok
      |-  ^-  (unit (list tank))
      ?:  ?=(@ lum)
        ?.(=(~ lum) ~ [~ ~])
      =+  [for=^$(q.ham q.q.ham, lum -.lum) aft=$(lum +.lum)]
      ?.  &(?=(^ for) ?=(^ aft))
        ~
      [~ u.for u.aft]
    ::
        {$bcwt *}
      |-  ^-  (unit tank)
      ?~  p.q.ham
        ~
      =+  wal=^$(q.ham i.p.q.ham)
      ?~  wal
        $(p.q.ham t.p.q.ham)
      wal
    ::
        {$plot *}
      =-  ?~  tok
            ~
          [~ %rose [[' ' ~] ['[' ~] [']' ~]] u.tok]
      ^=  tok
      |-  ^-  (unit (list tank))
      ?~  p.q.ham
        ~
      ?:  ?=({* ~} p.q.ham)
        =+  wal=^$(q.ham i.p.q.ham)
        ?~(wal ~ [~ [u.wal ~]])
      ?@  lum
        ~
      =+  gim=^$(q.ham i.p.q.ham, lum -.lum)
      ?~  gim
        ~
      =+  myd=$(p.q.ham t.p.q.ham, lum +.lum)
      ?~  myd
        ~
      [~ u.gim u.myd]
    ::
        {$pear *}
      ?.  =(lum q.q.ham)
        ~
      =.  p.q.ham
        (rash p.q.ham ;~(sfix (cook crip (star low)) (star hig)))
      =+  fox=$(q.ham [%mato p.q.ham])
      ?>  ?=({~ $leaf ^} fox)
      ?:  ?=(?($n $tas) p.q.ham)
        fox
      [~ %leaf '%' p.u.fox]
    ::
        {$stop *}
      ?:  (~(has in gil) [p.q.ham lum])  ~
      =+  kep=(~(get by p.ham) p.q.ham)
      ?~  kep
        ~|([%stop-loss p.q.ham] !!)
      $(gil (~(put in gil) [p.q.ham lum]), q.ham u.kep)
    ::
        {$tree *}
      =-  ?~  tok
            ~
          [~ %rose [[' ' ~] ['{' ~] ['}' ~]] u.tok]
      ^=  tok
      =+  tuk=*(list tank)
      |-  ^-  (unit (list tank))
      ?:  =(~ lum)
        [~ tuk]
      ?.  ?=({n/* l/* r/*} lum)
        ~
      =+  rol=$(lum r.lum)
      ?~  rol
        ~
      =+  tim=^$(q.ham q.q.ham, lum n.lum)
      ?~  tim
        ~
      $(lum l.lum, tuk [u.tim u.rol])
    ::
        {$unit *}
      ?@  lum
        ?.(=(~ lum) ~ [~ %leaf '~' ~])
      ?.  =(~ -.lum)
        ~
      =+  wal=$(q.ham q.q.ham, lum +.lum)
      ?~  wal
        ~
      [~ %rose [[' ' ~] ['[' ~] [']' ~]] [%leaf '~' ~] u.wal ~]
    ==
  ::
  ++  doge
    |=  ham/cape
    =-  ?+  woz  woz
          {$list * {$mato $'ta'}}  %path
          {$list * {$mato $'t'}}   %wall
          {$list * {$mato $'tD'}}  %yarn
          {$list * $yarn}          %wool
        ==
    ^=  woz
    ^-  wine
    ?.  ?=({$stop *} q.ham)
      ?:  ?&  ?=  {$bcwt {$pear $n $0} {$plot {$pear $n $0} {$face *} ~} ~}
                q.ham
              =(1 (met 3 p.i.t.p.i.t.p.q.ham))
          ==
        [%unit =<([p q] i.t.p.i.t.p.q.ham)]
      q.ham
    =+  may=(~(get by p.ham) p.q.ham)
    ?~  may
      q.ham
    =+  nul=[%pear %n 0]
    ?.  ?&  ?=({$bcwt *} u.may)
            ?=({* * ~} p.u.may)
            |(=(nul i.p.u.may) =(nul i.t.p.u.may))
        ==
      q.ham
    =+  din=?:(=(nul i.p.u.may) i.t.p.u.may i.p.u.may)
    ?:  ?&  ?=({$plot {$face *} {$face * $stop *} ~} din)
            =(p.q.ham p.q.i.t.p.din)
            =(1 (met 3 p.i.p.din))
            =(1 (met 3 p.i.t.p.din))
        ==
      :+  %list
        (cat 3 p.i.p.din p.i.t.p.din)
      q.i.p.din
    ?:  ?&  ?=  $:  $plot
                    {$face *}
                    {$face * $stop *}
                    {{$face * $stop *} ~}
                ==
                din
            =(p.q.ham p.q.i.t.p.din)
            =(p.q.ham p.q.i.t.t.p.din)
            =(1 (met 3 p.i.p.din))
            =(1 (met 3 p.i.t.p.din))
            =(1 (met 3 p.i.t.t.p.din))
        ==
      :+  %tree
        %^    cat
            3
          p.i.p.din
        (cat 3 p.i.t.p.din p.i.t.t.p.din)
      q.i.p.din
    q.ham
  ::
  ++  dole
    ^-  cape
    =+  gil=*(set type)
    =+  dex=[p=*(map type @) q=*(map @ wine)]
    =<  [q.p q]
    |-  ^-  {p/{p/(map type @) q/(map @ wine)} q/wine}
    =-  [p.tez (doge q.p.tez q.tez)]
    ^=  tez
    ^-  {p/{p/(map type @) q/(map @ wine)} q/wine}
    ?:  (~(meet ut sut) -:!>(*type))
      [dex %type]
    ?-    sut
        $noun      [dex sut]
        $void      [dex sut]
        {$atom *}  [dex ?~(q.sut [%mato p.sut] [%pear p.sut u.q.sut])]
        {$cell *}
      =+  hin=$(sut p.sut)
      =+  yon=$(dex p.hin, sut q.sut)
      :-  p.yon
      :-  %plot
      ?:(?=({$plot *} q.yon) [q.hin p.q.yon] [q.hin q.yon ~])
    ::
        {$core *}
      =+  yad=$(sut p.sut)
      :-  p.yad
      =+  ^=  doy  ^-  {p/(list @ta) q/wine}
          ?:  ?=({$core *} q.yad)
            [p.q.yad q.q.yad]
          [~ q.yad]
      :-  %core
      :_  q.doy
      :_  p.doy
      %^  cat  3
        %~  rent  co
            :+  %$  %ud
            %-  ~(rep by (~(run by q.s.q.sut) |=(tomb ~(wyt by q))))
            |=([[@ a=@u] b=@u] (add a b))
        ==
      %^  cat  3
        ?-(p.q.sut $gold '.', $iron '|', $lead '?', $zinc '&')
      =+  gum=(mug q.s.q.sut)
      %+  can  3
      :~  [1 (add 'a' (mod gum 26))]
          [1 (add 'a' (mod (div gum 26) 26))]
          [1 (add 'a' (mod (div gum 676) 26))]
      ==
    ::
        {$help *}
      $(sut q.sut)
    ::
        {$face *}
      =+  yad=$(sut q.sut)
      ?^(q.p.sut yad [p.yad [%face q.p.sut q.yad]])
    ::
        {$fork *}
      =+  yed=~(tap in p.sut)
      =-  [p [%bcwt q]]
      |-  ^-  {p/{p/(map type @) q/(map @ wine)} q/(list wine)}
      ?~  yed
        [dex ~]
      =+  mor=$(yed t.yed)
      =+  dis=^$(dex p.mor, sut i.yed)
      [p.dis q.dis q.mor]
    ::
        {$hold *}
      =+  hey=(~(get by p.dex) sut)
      ?^  hey
        [dex [%stop u.hey]]
      ?:  (~(has in gil) sut)
        =+  dyr=+(~(wyt by p.dex))
        [[(~(put by p.dex) sut dyr) q.dex] [%stop dyr]]
      =+  rom=$(gil (~(put in gil) sut), sut ~(repo ut sut))
      =+  rey=(~(get by p.p.rom) sut)
      ?~  rey
        rom
      [[p.p.rom (~(put by q.p.rom) u.rey q.rom)] [%stop u.rey]]
    ==
  ::
  ++  duck  (dial dole)
  --