urbit/base/pub/doc/hoon/library/3be.md

section 3bE, tree sync

++invert-miso

++  invert-miso                                         ::  invert miso
  |=  mis=miso
  ?-  -.mis
    %del  [%ins p.mis]
    %ins  [%del p.mis]
    %mut  [%mut (limp p.mis)]
  ==
::

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++cosh

++  cosh                                                ::  locally rehash
  |=  ank=ankh                                          ::  NB v/unix.c
  ank(p rehash:(zu ank))
::

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++cost

++  cost                                                ::  new external patch
  |=  [bus=ankh ank=ankh]                               ::  NB v/unix.c
  ^-  soba
  :-  [p.ank p.bus] 
  %-  flop
  myz:(change-tree:(zu ank) %c bus)
::

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++loth

++  loth
  |=  pat=(map path ,*)
  ^-  (set path)
  %+  roll  (~(tap by pat) ~)
  |=  [[p=path *] q=(set path)]
  %.  p  %~  put  in  q
::

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++luth

++  luth
  |=  [p=(map path ,*) q=(map path ,*)]                 ::  merge keysets
  ^-  (set path)
  (~(uni in (loth p)) (loth q))
::

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++blob-to-lobe

++  blob-to-lobe                                        ::  p.blob
  |=  p=blob
  ^-  lobe
  ?-   -.p
     %delta  p.p
     %direct  p.p
     %indirect  p.p
  ==
::

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++ze

++  ze
  |_  [lim=@da dome rang]

XX document

++aeon-to-tako

  ++  aeon-to-tako  ~(got by hit)

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++make-yaki

  ++  make-yaki                                         ::  make yaki
    |=  [p=(list tako) q=(map path lobe) t=@da]
    ^-  yaki
    =+  ^=  has
        %^  cat  7  (sham [%yaki (roll p add) q t])
        (sham [%tako (roll p add) q t])
    [p q has t]
  ::

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++tako-to-yaki

  ++  tako-to-yaki  ~(got by hut)                       ::  grab yaki

XX document

++lobe-to-blob

  ++  lobe-to-blob  ~(got by lat)                       ::  grab blob

XX document

++lobe-to-noun

  ++  lobe-to-noun                                      ::  grab blob
    |=  p=lobe                                          ::  ^-  *
    %-  blob-to-noun  
    (lobe-to-blob p)
  ::

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++make-direct

  ++  make-direct                                       ::  make blob
    |=  [p=* q=umph]
    ^-  blob
    [%direct (mug p) p q]
  ::

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++make-delta

  ++  make-delta                                        ::  make blob delta
    |=  [p=lobe q=udon]
    ^-  blob
    =+  t=[%delta 0 p q]
    =+  z=(blob-to-noun t)
    =+  ^=  has
        %^  cat  7  (sham [%blob z])
        (sham [%lobe z])
    [%delta has p q]
  ::

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++blob-to-umph

  ++  blob-to-umph                                      ::  blob umph [prep]
    |=  p=blob                                          ::  used in merge
    ^-  umph
    ?-   -.p
       %delta  p.r.p
       %direct  r.p
       %indirect  p.r.p
    ==
  ::

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++blob-to-noun

  ++  blob-to-noun                                      ::  grab blob
    |=  p=blob
    ?-   -.p
       %delta  (lump r.p (lobe-to-noun q.p))
       %direct  q.p
       %indirect  q.p
    ==
  ::
  ::
  ::

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++diff-yakis

  ++  diff-yakis                                        ::  fundamental diff
    |=  [p=yaki q=yaki]
    ^-  (map path miso)
    %+  roll  (~(tap in (luth q.p q.q)) ~)
    |=  [pat=path yeb=(map path miso)]
    =+  leb=(~(get by q.p) pat)
    =+  lob=(~(get by q.q) pat)
    ?~  leb  (~(put by yeb) pat [%ins (lobe-to-noun (need lob))])
    ?~  lob  (~(put by yeb) pat [%del (lobe-to-noun (need leb))])
    ?:  =(u.leb u.lob)  yeb
    =+  veq=(lobe-to-blob u.leb)
    =+  voq=(lobe-to-blob u.lob)
    %+  ~(put by yeb)  pat
    :-  %mut  
    ?:  &(?=(%delta -.voq) =(u.leb q.voq))              ::  avoid diff
      r.voq
    =+  zeq=(blob-to-noun veq)
    =+  zoq=(blob-to-noun voq)
    ((diff (blob-to-umph (lobe-to-blob u.leb))) zeq zoq)
  ::

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++lobes-at-path

  ++  lobes-at-path                                     ::    lobes-at-path:ze
    |=  [oan=aeon pax=path]                             ::  data at path
    ^-  (map path lobe)
    ?:  =(0 oan)  ~
    %-  mo
    %+  skim
      %.  ~
      %~  tap  by
      =<  q
      %-  tako-to-yaki
      %-  aeon-to-tako
      oan
    |=  [p=path q=lobe]
    ?|  ?=(~ pax)
        ?&  !?=(~ p)
            =(-.pax -.p)
            $(p +.p, pax +.pax)
    ==  ==
  ::

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++case-to-aeon

  ++  case-to-aeon                                      ::    case-to-aeon:ze
    |=  lok=case                                        ::  act count through
    ^-  (unit aeon)
    ?-    -.lok
        %da
      ?:  (gth p.lok lim)  ~
      |-  ^-  (unit aeon)
      ?:  =(0 let)  [~ 0]                               ::  avoid underflow
      ?:  %+  gte  p.lok 
          =<  t
          %-  tako-to-yaki
          %-  aeon-to-tako
          let
        [~ let]
      $(let (dec let))
    ::
        %tas  (~(get by lab) p.lok)
        %ud   ?:((gth p.lok let) ~ [~ p.lok])
    ==
  ::

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++as-arch

  ++  as-arch                                           ::    as-arch:ze
    ^-  arch                                            ::  arch report
    :+  p.ank
      ?~(q.ank ~ [~ p.u.q.ank])
    |-  ^-  (map ,@ta ,~)
    ?~  r.ank  ~
    [[p.n.r.ank ~] $(r.ank l.r.ank) $(r.ank r.r.ank)]
  ::

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++reachable-takos

  ++  reachable-takos                                   ::  reachable
    |=  p=tako                                          ::  XX slow
    ^-  (set tako)
    =+  y=(tako-to-yaki p)
    =+  t=(~(put in _(set tako)) p)
    %+  roll  p.y
    |=  [q=tako s=_t]
    ?:  (~(has in s) q)                                 ::  already done
      s                                                 ::  hence skip
    (~(uni in s) ^$(p q))                               ::  otherwise traverse
  ::

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++new-lobes

  ++  new-lobes                                         ::  object hash set
    |=  [b=(set lobe) a=(set tako)]                     ::  that aren't in b
    ^-  (set lobe)
    %+  roll  (~(tap in a) ~)
    |=  [tak=tako bar=(set lobe)]
    ^-  (set lobe)
    =+  yak=(tako-to-yaki tak)
    %+  roll  (~(tap by q.yak) ~)
    |=  [[path lob=lobe] far=_bar]
    ^-  (set lobe)
    ?~  (~(has in b) lob)                               ::  don't need
      far
    =+  gar=(lobe-to-blob lob)
    ?-  -.gar
      %direct  (~(put in far) lob)
      %delta  (~(put in $(lob q.gar)) lob)
      %indirect  (~(put in $(lob s.gar)) lob)
    ==
  ::

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++new-lobes-takos

  ++  new-lobes-takos                                   ::  garg & repack
    |=  [b=(set lobe) a=(set tako)]
    ^-  [(set tako) (set lobe)]
    [a (new-lobes b a)]
  ::

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++reachable-between-takos

  ++  reachable-between-takos
    |=  [a=(unit tako) b=tako]                          ::  pack a through b
    ^-  [(set tako) (set lobe)]
    =+  ^=  sar 
        ?~  a  ~
        (reachable-takos r:(tako-to-yaki u.a))
    =+  yak=`yaki`(tako-to-yaki b)
    %+  new-lobes-takos  (new-lobes ~ sar)              ::  get lobes
    |-  ^-  (set tako)                                  ::  walk onto sar
    ?:  (~(has in sar) r.yak)
      ~
    =+  ber=`(set tako)`(~(put in `(set tako)`~) `tako`r.yak)
    %-  ~(uni in ber)
    ^-  (set tako)
    %+  roll  p.yak
    |=  [yek=tako bar=(set tako)]
    ^-  (set tako)
    ?:  (~(has in bar) yek)                             ::  save some time
      bar
    %-  ~(uni in bar)
    ^$(yak (tako-to-yaki yek))
  ::

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++takos-to-yakis

  ++  takos-to-yakis                                    ::  trivial
    |=  a=(set tako)
    ^-  (set yaki)
    (sa (turn (~(tap by a)) tako-to-yaki))
  ::

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++lobes-to-blobs

  ++  lobes-to-blobs                                    ::  trivial
    |=  a=(set lobe)
    ^-  (set blob)
    (sa (turn (~(tap by a)) lobe-to-blob))
  ::

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++make-nako

  ++  make-nako                                         ::  gack a through b
    |=  [a=aeon b=aeon]
    ^-  [(map aeon tako) aeon (set yaki) (set blob)]
    :_  :-  b
        =-  [(takos-to-yakis -<) (lobes-to-blobs ->)]
        %+  reachable-between-takos
          (~(get by hit) a)                             ::  if a not found, a=0
        (aeon-to-tako b)
    ^-  (map aeon tako)
    %-  mo  %+  skim  (~(tap by hit) ~)
    |=  [p=aeon *]
    &((gth p a) (lte p b))
  ::
  ::::::::::::::::::::::::::::::::::::::::::::::::::::::::

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++query

  ++  query                                             ::    query:ze
    |=  ren=?(%u %v %x %y %z)                           ::  endpoint query
    ^-  (unit ,*)
    ?-  ren
      %u  [~ `rang`+<+>.query]
      %v  [~ `dome`+<+<.query]
      %x  ?~(q.ank ~ [~ q.u.q.ank])
      %y  [~ as-arch]
      %z  [~ ank]
    ==
  ::

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++rewind

  ++  rewind                                            ::    rewind:ze
    |=  oan=aeon                                        ::  rewind to aeon
    ^+  +>
    ?:  =(let oan)  +>
    ?:  (gth oan let)  !!                               ::  don't have version
    +>(ank (checkout-ankh q:(tako-to-yaki (aeon-to-tako oan))), let oan)
  ::
  ::::

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++update-lat

  ++  update-lat                                        ::   update-lat:ze
    |=  [lag=(map path blob) sta=(map lobe blob)]       ::  fix lat
    ^-  [(map lobe blob) (map path lobe)]
    %+  roll  (~(tap by lag) ~)
    |=  [[pat=path bar=blob] [lut=_sta gar=(map path lobe)]]
    ?~  (~(has by lut) p.bar)
      [lut (~(put by gar) pat p.bar)]
    :-  (~(put by lut) p.bar bar)
    (~(put by gar) pat p.bar)
  ::

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++apply-changes

  ++  apply-changes                                     ::   apply-changes:ze
    |=  lar=(list ,[p=path q=miso])                     ::  store changes
    ^-  (map path blob)
    =+  ^=  hat                                         ::  current state
        ?:  =(let 0)                                    ::  initial commit
          ~                                             ::  has nothing
        =<  q
        %-  tako-to-yaki
        %-  aeon-to-tako
        let
    %-  |=  bar=(map path blob)                         ::  find unchanged
        =+  sar=(sa (turn lar |=([p=path *] p)))        ::  changed paths
        %+  roll  (~(tap by hat) ~)
        |=  [[pat=path gar=lobe] bat=_bar]
        ?:  (~(has in sar) pat)                         ::  has update
          bat
        (~(put by bat) pat (lobe-to-blob gar))  ::  use original
    %+  roll  lar
    |=  [[pat=path mys=miso] bar=(map path blob)]
    ^+  bar
    ?-    -.mys
        %ins                                            ::  insert if not exist
      ?:  (~(has by bar) pat)  !!                       ::
      ?:  (~(has by hat) pat)  !!                       ::
      (~(put by bar) pat (make-direct p.mys %c))        ::  TODO content type?
        %del                                            ::  delete if exists
      ?.  |((~(has by hat) pat) (~(has by bar) pat))  !!
      (~(del by bar) pat)
        %mut                                            ::  mutate, must exist
      =+  ber=(~(get by bar) pat)
      ?~  ber
        =+  har=(~(get by hat) pat)
        ?~  har  !!
        %+  ~(put by bar)  pat
        (make-delta u.har p.mys)
      %+  ~(put by bar)  pat
      (make-delta p.u.ber p.mys)
    ==

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++checkout-ankh

  ++  checkout-ankh                                     ::    checkout-ankh:ze
    |=  hat=(map path lobe)                             ::  checkout commit
    ^-  ankh
    %-  cosh
    %+  roll  (~(tap by hat) ~)
    |=  [[pat=path bar=lobe] ank=ankh]
    ^-  ankh
    %-  cosh
    ?~  pat
      =+  zar=(lobe-to-noun bar)
      ank(q [~ (sham zar) zar])
    =+  nak=(~(get by r.ank) i.pat)
    %=  ank
      r  %+  ~(put by r.ank)  i.pat 
         $(pat t.pat, ank (fall nak _ankh))
    ==
  ::

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++forge-yaki

  ++  forge-yaki                                        ::    forge-yaki:ze
    |=  [wen=@da par=(unit tako) lem=soba]              ::  forge yaki
    =+  ^=  per
        ?~  par  ~
        ~[u.par]
    =+  gar=(update-lat (apply-changes q.lem) lat)
    :-  %^  make-yaki  per  +.gar  wen                  ::  from existing diff
    -.gar                                               ::  fix lat
  ::

XX document

++forge-nori

  ++  forge-nori                                        ::    forge-nori:ze
    |=  yak=yaki                                        ::  forge nori (ugly op)
    ^-  nori                                            ::  basically zerg w/ nori
    ?~  p.yak  !!                                       ::  no parent -> can't diff
    :+  %&  *cart                                       ::  diff w/ 1st parent
    (~(tap by (diff-yakis (tako-to-yaki i.p.yak) yak)) ~)
  ::
  ::  graph algorithms (bottleneck)
  ::

XX document

++reduce-merge-points

  ++  reduce-merge-points                             ::  reduce merge points
    |=  unk=(set yaki)                                ::  maybe need jet
    =|  gud=(set yaki)
    =+  ^=  zar
        ^-  (map tako (set tako))
        %+  roll  (~(tap in unk) ~)
        |=  [yak=yaki qar=(map tako (set tako))]
        (~(put by qar) r.yak (reachable-takos r.yak))
    |-  
    ^-  (set yaki)
    ?~  unk  gud
    =+  tek=`yaki`n.unk
    =+  bun=(~(del in `(set yaki)`unk) tek)
    ?:  %+  roll  (~(tap by (~(uni in gud) bun)) ~)   ::  only good + unknown
        |=  [tak=yaki god=?]
        ^-  ?
        ?.  god  god
        (~(has in (~(got by zar) r.tak)) tek)
      $(gud (~(put in gud) tek), unk bun)
    $(unk bun)
  ::

XX document

++future-find-merge-points

  ++  future-find-merge-points                        ::  merge points fast
    |=  [p=yaki q=yaki]                               ::  (future zeal)
    ^-  (set yaki)                                    ::  zear still uses zule
    %-  reduce-merge-points                           ::  this is test-only
    =+  s=(~(put in _(set tako)) r.p)                 ::  not actually used
    =+  t=(~(put in _(set tako)) t.p)                 ::  but might be active
    =|  u=(set yaki)                                  ::  eventually
    |-  ^-  (set yaki)
    =+  v=(~(int in s) t)                             ::  found common
    =+  ^=  qez                                       ::  drop common
        ^-  [s=(set tako) t=(set tako)]
        %+  roll  (~(tap in v) ~)
        |=  [tak=tako bar=_s zar=_t]
        [(~(del in bar) tak) (~(del in zar) tak)]
    ?:  &(=(~ s.qez) =(~ s.qez))
      (~(uni in u) (takos-to-yakis v))
    %=  $
      u  (~(uni in u) (takos-to-yakis v))
      s  (add-parents s.qez)
      t  (add-parents t.qez)
    ==
  ::

XX document

++add-parents

  ++  add-parents                                     ::  expand set
    |=  qez=(set tako)
    ^-  (set tako)
    %+  roll  (~(tap in qez) ~)
    |=  [tak=tako zar=(set tako)]
    %-  ~(uni in (~(put in zar) tak))
    (sa p:(tako-to-yaki tak))
  ::

XX document

++find-merge-points

  ++  find-merge-points                               ::  merge points
    |=  [p=yaki q=yaki]                               ::  maybe need jet
    ^-  (set yaki)
    %-  reduce-merge-points
    =+  r=(reachable-takos r.p)
    |-  ^-  (set yaki)
    ?:  (~(has in r) q)  (~(put in _(set yaki)) q)    ::  done 
    %+  roll  p.q
    |=  [t=tako s=(set yaki)]
    ?:  (~(has in r) t)
      (~(put in s) (tako-to-yaki t))                 ::  found
    (~(uni in s) ^$(q (tako-to-yaki t)))             ::  traverse
  ::
  ::  merge logic
  ::

XX document

++clean

  ++  clean                                          ::  clean
    |=  wig=(urge)
    ^-  (urge)
    ?~  wig  ~
    ?~  t.wig  wig
    ?:  ?=(%& -.i.wig)
      ?:  ?=(%& -.i.t.wig)
        $(wig [[%& (add p.i.wig p.i.t.wig)] t.t.wig])
      [i.wig $(wig t.wig)]
    ?:  ?=(%| -.i.t.wig)
      $(wig [[%| (welp p.i.wig p.i.t.wig) (welp q.i.wig q.i.t.wig)] t.t.wig])
    [i.wig $(wig t.wig)]
  ::

XX document

++match-conflict

  ++  match-conflict                                ::  match conflict
    |=  [us=[ship desk] th=[ship desk] p=(urge) q=(urge) r=(list)]
    ^-  [p=[p=(list) q=(list)] q=[p=(urge) q=(urge) r=(list)]]
    =+  cas=(hard (list ,@t))
    =+  cat=(hard (urge ,@t))
    =+  mar=(match-merge (cat p) (cat q) (cas r))
    :-  :-  s.q.mar 
        (annotate us th p.p.mar q.p.mar s.q.mar)    ::  annotation
    :-  p.q.mar
    :-  q.q.mar
    r.q.mar
  ::

XX document

++annotate

  ++  annotate                                      ::  annotate conflict
    |=  [us=[ship desk] th=[ship desk] p=(list ,@t) q=(list ,@t) r=(list ,@t)]
    ^-  (list ,@t)
    %-  zing
    ^-  (list (list ,@t))
    %-  flop
    ^-  (list (list ,@t))
    :-  :_  ~
        %^  cat  3  '<<<<<<<<<<<<' 
        %^  cat  3  ' '
        %^  cat  3  `@t`(scot %p -.us)
        %^  cat  3  '/'
        +.us
    :-  p
    :-  ~['------------']
    :-  r
    :-  ~['++++++++++++']
    :-  q
    :-  :_  ~
        %^  cat  3  '>>>>>>>>>>>>' 
        %^  cat  3  ' '
        %^  cat  3  `@t`(scot %p -.th)
        %^  cat  3  '/'
        +.th
    ~
  ::

XX document

++match-merge

  ++  match-merge                                   ::  match merge
    |=  [p=(urge ,@t) q=(urge ,@t) r=(list ,@t)]    ::  resolve conflict
    =|  s=[p=(list ,@t) q=(list ,@t)]               ::  p chunk
    =|  t=[p=(list ,@t) q=(list ,@t)]               ::  q chunk
    |-  ^-  $:  p=[p=(list ,@t) q=(list ,@t)]
                $=  q
                $:  p=(urge ,@t)
                    q=(urge ,@t)
                    r=(list ,@t)
                    s=(list ,@t)
            ==  ==
    ?~  p  [[q.s q.t] p q r p.s]                    ::  can't be conflict
    ?~  q  [[q.s q.t] p q r p.s]                    ::  can't be conflict
    ?-  -.i.p
      %&  ?>  ?=(%| -.i.q)                          ::  is possibly conflict
          ?:  (gte p.i.p (lent p.i.q))              ::  trivial resolve
            :::-  (weld p.s p.i.q)                    ::  extend to q
            :-  :-  (welp (flop (scag (lent p.i.q) r)) q.s)
                (welp q.i.q q.t)
            :-  ?:  =(p.i.p (lent p.i.q))  t.p
                [[%& (sub p.i.p (lent p.i.q))] t.p]
            :-  t.q
            :-  (flop (slag (lent p.i.q) r))
            (welp (flop (scag (lent p.i.q) r)) p.s)
          =+  tex=(flop (scag p.i.p r))
          ?~  t.p                                   ::  extend to end
            %=  $
              ::s  [(welp p.s tex) (welp q.s tex)]
              p  ~[[%| [tex tex]]]
              ::r  (slag p.i.p r)
            ==
          ?>  ?=(%| -.i.t.p)                        ::  fake skip
          %=  $
            ::s  [(welp p.s tex) (welp q.s tex)]
            p  [[%| [(welp p.i.t.p tex) (welp q.i.t.p tex)]] t.t.p]
            ::r  (slag p.i.p r)
          ==
      %|  ?-  -.i.q
             %&  =+  mar=$(p q, q p, s t, t s)      ::  swap recursion
                 [[q.p.mar p.p.mar] q.q.mar p.q.mar r.q.mar s.q.mar]
             %|  ?:  =((lent p.i.p) (lent p.i.q))   ::  perfect conflict
                   ?>  =(p.i.p p.i.q)               ::  sane conflict
                   :-  :-  (welp q.i.p q.s)
                       (welp q.i.q q.t)
                   :-  t.p 
                   :-  t.q 
                   :-  (scag (lent p.i.p) r)
                   (welp (flop (scag (lent p.i.p) r)) p.s)
                 ?.  (lth (lent p.i.p) (lent p.i.q))
                   =+  mar=$(p q, q p, s t, t s)    ::  swap recursion
                   [[q.p.mar p.p.mar] q.q.mar p.q.mar r.q.mar s.q.mar]
                 ?>  .=  p.i.p                      ::  sane conflict
                     (slag (sub (lent p.i.q) (lent p.i.p)) p.i.q)
                 %=  $                              ::  extend p
                   p  t.p
                   p.s  (welp p.i.p p.s)
                   q.s  (welp q.i.p q.s)
                   p.t  (welp p.i.p p.s)            ::  subset of q
                   q.t  (welp q.i.q q.s)            ::  just consume all out
                   q  [[%| (scag (sub (lent p.i.q) (lent p.i.p)) p.i.q) ~] t.q]
                   r  (slag (lent p.i.p) r)
                 ==
             ==
      ==

XX document

++qeal

  ++  qeal                                          ::  merge p,q
    |*  [us=[ship desk] th=[ship desk] pat=path p=miso q=miso r=(list) con=?]
    ^-  miso                                        ::  in case of conflict
    ~|  %qeal-fail
    ?>  ?=(%mut -.p)
    ?>  ?=(%mut -.q)
    ?>  ?=(%c -.q.p.p)
    ?>  ?=(%c -.q.p.q)
    =+  s=(clean p.q.p.p)
    =+  t=(clean p.q.p.q)
    :-  %mut
    :-  %c  ::  todo is this p.p.p?
    :-  %c
    |-  ^-  (urge)
    ::?~  s  ?:  (qual t)  t
    ::       ~|  %qail-conflict  !!
    ::?~  t  ?:  (qual s)  s
    ::       ~|  %qail-conflict  !!
    ?~  s  t
    ?~  t  s
    ?-    -.i.s
        %&
      ?-    -.i.t
          %&
        ?:  =(p.i.s p.i.t)
          [i.s $(s t.s, t t.t, r (slag p.i.s r))]
        ?:  (gth p.i.s p.i.t)
          [i.t $(t t.t, p.i.s (sub p.i.s p.i.t), r (slag p.i.t r))]
        [i.s $(s t.s, p.i.t (sub p.i.t p.i.s), r (slag p.i.s r))]
          %|
        ?:  =(p.i.s (lent p.i.t))
          [i.t $(s t.s, t t.t, r (slag p.i.s r))]
        ?:  (gth p.i.s (lent p.i.t))
          :-  i.t 
          $(t t.t, p.i.s (sub p.i.s (lent p.i.t)), r (slag (lent p.i.t) r))
        ?.  con  ~|  %quil-conflict  !!           ::  conflict
        ~&  [%quil-conflict-soft pat]
        =+  mar=(match-conflict us th s t r)
        [[%| p.mar] $(s p.q.mar, t q.q.mar, r r.q.mar)]
      ==
        %|
      ?-    -.i.t
          %|
        ?.  con  ~|  %quil-conflict  !!
        ~&  [%quil-conflict-soft pat]
        =+  mar=(match-conflict us th s t r)
        [[%| p.mar] $(s p.q.mar, t q.q.mar, r r.q.mar)]
          %&
        ?:  =(p.i.t (lent p.i.s))
          [i.s $(s t.s, t t.t, r (slag p.i.t r))]
        ?:  (gth p.i.t (lent p.i.s))
          :-  i.s
          $(s t.s, p.i.t (sub p.i.t (lent p.i.s)), r (slag (lent p.i.s) r))
        ?.  con  ~|  %quil-conflict  !!
        ~&  [%quil-conflict-soft pat]
        =+  mar=(match-conflict us th s t r)
        [[%| p.mar] $(s p.q.mar, t q.q.mar, r r.q.mar)]
      ==
    ==

XX document

++quil

  ++  quil                                          ::  merge p,q
    |=  $:  us=[ship desk]
            th=[ship desk]
            pat=path
            p=(unit miso)
            q=(unit miso)
            r=(unit (list))
            con=?
        ==
    ^-  (unit miso)
    ?~  p  q                                        ::  trivial
    ?~  q  p                                        ::  trivial
    ?-  -.u.p
      %ins  ?>  ?=(%ins -.u.q)
            ?.  con  !!
            %-  some
            :-  %ins
            %-  role
            %-  annotate
            :-  us 
            :-  th
            :-  (lore ((hard ,@) p.u.p)) 
            :-  (lore ((hard ,@) p.u.q))
            ~
      %del  p
      %mut  ?>  ?=(%mut -.u.q)
            %-  some
            %^  qeal  us  th
            :^  pat  u.p  u.q                       ::  merge p,q
            :-  %-  need  r
            con
    ==
  ::

XX document

++meld

  ++  meld                                          ::  merge p,q from r
    |=  [p=yaki q=yaki r=yaki con=? us=[ship desk] th=[ship desk]]
    ^-  (map path blob)
    =+  s=(diff-yakis r p)
    =+  t=(diff-yakis r q)
    =+  lut=(luth s t)
    %-  |=  res=(map path blob)                        ::  add old
        ^-  (map path blob)
        %-  ~(uni by res)
        %-  mo
        %+  turn  
          %+  skip  (~(tap by q.r) ~)                  ::  loop through old
          |=  [pat=path bar=lobe]  ^-  ?
          (~(has in lut) pat)                          ::  skip updated
        |=  [pat=path bar=lobe]  ^-  [path blob]
        [pat (lobe-to-blob bar)]                       ::  lookup objects
    %+  roll  (~(tap in (luth s t)) ~)
    |=  [pat=path res=(map path blob)]
    =+  ^=  v
        %-  need
        %^  quil  us  th
        :-  pat
        :+  (~(get by s) pat)
          (~(get by t) pat)
        :_  con
        %-  %-  lift  lore
        %-  %-  lift  %-  hard  ,@                     ::  for %c
        %-  %-  lift  lobe-to-noun
        %-  ~(get by q.r)
        pat
    ?-    -.v
        %del  res                                      ::  no longer exists
        %ins                                           ::  new file
      %+  ~(put by res)  pat 
      %+  make-direct  p.v  %c                         ::  TODO content type?
        %mut                                           ::  patch from r
      %+  ~(put by res)  pat
      %-  make-direct
      :_  %c
      %+  lump  p.v
      %-  lobe-to-noun
      %-  ~(got by q.r)  pat
    ==
  ::
  ::  merge types
  ::

XX document

++mate

  ++  mate                                          ::  merge p,q
    |=  con=?                                       ::  %mate, %meld
    |=  [p=yaki q=yaki us=[ship desk] th=[ship desk]]
    ^-  (map path blob)
    =+  r=(~(tap in (find-merge-points p q)) ~)
    ?~  r
      ~|(%mate-no-ancestor !!)
    ?:  =(1 (lent r))
      (meld p q i.r con us th)
    ~|(%mate-criss-cross !!)
  ::

XX document

++keep

  ++  keep                                          ::  %this
    |=  [p=yaki q=yaki [ship desk] [ship desk]]
    ^-  (map path blob)
    %+  roll  (~(tap by q.p) ~)
    |=  [[pat=path lob=lobe] zar=(map path blob)]
    ^-  (map path blob)
    (~(put by zar) pat (lobe-to-blob lob))
  ::

XX document

++drop

  ++  drop                                          ::  %that
    |=  [p=yaki q=yaki r=[ship desk] s=[ship desk]]
    ^-  (map path blob)
    (keep q p r s)
  ::

XX document

++forge

  ++  forge                                         ::  %forge
    |=  [p=yaki q=yaki s=[ship desk] t=[ship desk]]
    ^-  (map path blob)
    =+  r=(~(tap in (find-merge-points p q)) ~)
    ?~  r
      ~|(%forge-no-ancestor !!)
    %-  |=  [r=yaki lut=(map lobe blob) hat=(map tako yaki)]
        =.  lat  lut
        =.  hut  hat
        (meld p q r & s t)                          ::  fake merge
    %+  roll  t.r                                   ::  fake ancestor
    |=  [par=yaki [for=_i.r lut=_lat hat=_hut]]
    =.  lat  lut
    =+  ^=  far
        ^-  (map path lobe)
        %-  ~(tur by (forge par for s t))
        |=  [k=path v=blob]  (blob-to-lobe v)
    =+  u=(make-yaki [r.par r.for ~] far `@da`0)    ::  fake yaki
    :-  u
    :_  (~(put by hat) r.u u)
    =<  -
    %-  update-lat
    :_  ~
    %-  ~(tur by q.u)
    |=  [path k=lobe]
    (lobe-to-blob k)
  ::
  ::  actual merge
  ::

XX document

++merge

  ++  merge
    |=  [us=[ship desk] th=[ship desk]]
    |=  [p=yaki q=yaki r=@da s=$+([yaki yaki [ship desk] [ship desk]] (map path blob))]
    ^-  [yaki (map path blob)]
    =+  u=(s p q us th)
    =+  ^=  t
        ^-  (map path lobe)
        %+  roll  (~(tap by u) ~)
        |=  [[pat=path bar=blob] yeb=(map path lobe)]
        (~(put by yeb) pat (blob-to-lobe bar))
    :_  u
    (make-yaki [r.p r.q ~] t r)
  ::

XX document

++strategy

  ++  strategy                                          ::  merge strategy
    |=  gem=?(%meld %mate %that %this)
    ?-  gem
      %meld  (mate %.y)
      %mate  (mate %.n)
      %this  keep
      %that  drop
    ==
  ::

XX document

++construct-merge

  ++  construct-merge                                   ::    construct-merge:ze
    |=  [gem=germ who=ship des=desk sab=saba now=@da]   ::  construct merge
    ^-  (unit (unit mizu))                              ::::::
    =+  for=s.sab                                       ::  foreign dome
    =+  mer=(merge [who des] [p.sab q.sab])
    ?-  gem
        %init                                           ::  force fine
          ?.  =(let 0)                                  ::  hell no
            !!
          =+  hot=(~(put by _(map aeon tako)) 1 (~(got by hit.for) let.for))
          [~ [~ [1 hot hut lat]]]                       ::  trivial
        %fine
          =+  der=(~(got by hit.for) let.for)
          =+  owr=(~(got by hit) let)
          ?:  =(der owr)
            [~ ~]
          ?:  (~(has in (reachable-takos owr)) der)
            [~ ~]
          ?.  (~(has in (reachable-takos der)) owr)
            ~                                          ::  not a fast forward
          ~&  [%merge-fine p.sab q.sab]
          [~ [~ [+(let) (~(put by hit) +(let) der) hut lat]]]
        ?(%mate %that %this %meld)
          =+  foreign-head=(tako-to-yaki (~(got by hit.for) let.for))
          =+  our-head=(tako-to-yaki (~(got by hit) let))
          ?:  =(r.foreign-head r.our-head)
            [~ ~]                                      ::  up to date
          ?:  (~(has in (reachable-takos r.our-head)) r.foreign-head)
            [~ ~]                                      ::  up to date
          ?:  ?&  |(=(gem %mate) =(gem %meld))
                  (~(has in (reachable-takos r.foreign-head)) r.our-head)
              ==
            $(gem %fine)                               ::  use fast forward
          =+  gar=(mer our-head foreign-head now (strategy gem))
          =+  yak=-.gar
          =+  hek=+.gar
          =.  lat  -:(update-lat hek ~)                ::  add new blobs
          =.  hut  (~(put by _(map tako yaki)) r.yak yak)
          =.  let  +(let)
          =.  hit  (~(put by _(map aeon tako)) let r.yak)
          [~ [~ [let hit hut lat]]]
    ==
  ::

XX document

++read

  ++  read                                              ::    read:ze
    |=  mun=mood                                        ::  read at point
    ^-  (unit)
    ?:  ?=(%v p.mun)
      [~ `dome`+<+<.read]
    ?:  &(?=(%w p.mun) !?=(%ud -.q.mun))
      ?^(r.mun ~ [~ let])
    ?:  ?=(%w p.mun)
      =+  ^=  yak
          %-  tako-to-yaki
          %-  aeon-to-tako
          let
      ?^(r.mun ~ [~ [t.yak (forge-nori yak)]])
      ::?>  ?=(^ hit)  ?^(r.mun ~ [~ i.hit])     ::  what do?? need [@da nori]
    (query(ank ank:(descend-path:(zu ank) r.mun)) p.mun)
  ::

XX document

++read-at-aeon

  ++  read-at-aeon                                      ::    read-at-aeon:ze
    |=  [oan=aeon mun=mood]                             ::  seek and read
    ^-  (unit)
    ?:  &(?=(%w p.mun) !?=(%ud -.q.mun))                ::  NB only for speed
      ?^(r.mun ~ [~ oan])
    (read:(rewind oan) mun)
  ::

XX document

++equiv

  ++  equiv                                             ::  test paths
    |=  [p=(map path lobe) q=(map path lobe)]
    ^-  ?
    %-  |=  qat=?
        ?.  qat  %.n
        %+  roll  (~(tap by q) ~)
        |=  [[pat=path lob=lobe] eq=?]
        ^-  ?
        ?.  eq  %.n
        (~(has by p) pat)
    %+  roll  (~(tap by p) ~)
    |=  [[pat=path lob=lobe] eq=?]
    ^-  ?
    ?.  eq  %.n
    =+  zat=(~(get by q) pat)
    ?~  zat  %.n
    =((lobe-to-noun u.zat) (lobe-to-noun lob))
  ::

XX document

++edit

  ++  edit                                              ::    edit:ze
    |=  [wen=@da lem=nori]                              ::  edit
    ^+  +>
    ?-  -.lem
      &  =+  ^=  yet 
             %+  forge-yaki  wen
             ?:  =(let 0)                               ::  initial import
               [~ q.lem]
             [(some r:(tako-to-yaki (aeon-to-tako let))) q.lem]
         =+  yak=-.yet
         =.  lat  +.yet                                 ::  merge objects
         ?.  ?|  =(0 let)
                 !=((lent p.yak) 1)
                 !(equiv q.yak q:(tako-to-yaki (aeon-to-tako let)))
             ==
           +>.$                                         ::  silently ignore
         =:  let  +(let)
             hit  (~(put by hit) +(let) r.yak)
             hut  (~(put by hut) r.yak yak)
         ==
         +>.$(ank (checkout-ankh q.yak))
      |  +>.$(lab ?<((~(has by lab) p.lem) (~(put by lab) p.lem let)))
    ==
  --
::

XX document

++zu

++  zu                                                  ::  filesystem
  |=  ank=ankh                                          ::  filesystem state
  =|  myz=(list ,[p=path q=miso])                       ::  changes in reverse
  =|  ram=path                                          ::  reverse path into
  |%

XX document

++rehash

  ++  rehash                                            ::  local rehash
    ^-  cash
    %+  mix  ?~(q.ank 0 p.u.q.ank)
    =+  axe=1
    |-  ^-  cash
    ?~  r.ank  _@
    ;:  mix
      (shaf %dash (mix axe (shaf %dush (mix p.n.r.ank p.q.n.r.ank))))
      $(r.ank l.r.ank, axe (peg axe 2))
      $(r.ank r.r.ank, axe (peg axe 3))
    ==
  ::

XX document

++update-hash

  ++  update-hash  %_(. p.ank rehash)                   ::  rehash and save

XX document

++ascend

  ++  ascend                                            ::  ascend
    |=  [lol=@ta kan=ankh]
    ^+  +>
    ?>  &(?=(^ ram) =(lol i.ram))
    %=    +>
        ram  t.ram
        ank
      ?:  =([0 ~ ~] ank)
        ?.  (~(has by r.kan) lol)  kan
        kan(r (~(del by r.kan) lol))
      kan(r (~(put by r.kan) lol ank))
    ==
  ::

XX document

++push-change

  ++  push-change                                       ::  add change
    |=  mis=miso
    ^+  +>
    +>(myz [[(flop ram) mis] myz])
  ::

XX document

++descend

  ++  descend                                           ::  descend
    |=  lol=@ta
    ^+  +>
    =+  you=(~(get by r.ank) lol)
    +>.$(ram [lol ram], ank ?~(you [*cash ~ ~] u.you))
  ::

XX document

++descend-path

  ++  descend-path                                      ::  descend recursively
    |=  way=path
    ^+  +>
    ?~(way +> $(way t.way, +> (descend i.way)))
  ::

XX document

++overwrite

  ++  overwrite                                         ::  write over
    |=  [pum=umph val=(unit ,[p=cash q=*])]
    ^+  +>
    ?~  q.ank
      ?~  val  +>
      (push-change %ins q.u.val)
    ?~  val
      (push-change %del q.u.q.ank)
    ?:  =(q.u.val q.u.q.ank)  +>
    (push-change %mut ((diff pum) q.u.q.ank q.u.val))
  ::

XX document

++change-tree

  ++  change-tree                                       ::  modify tree
    |=  [pum=umph bus=ankh]
    ^+  +>
    =.  +>  (overwrite pum q.bus)
    =+  [yeg=(~(tap by r.ank) ~) gey=(~(tap by r.bus) ~)]
    =.  +>.$
      |-  ^+  +>.^$
      ?~  yeg  +>.^$
      ?:  (~(has by r.bus) p.i.yeg)  $(yeg t.yeg)
      $(yeg t.yeg, myz myz:rm-r(ank q.i.yeg, ram [p.i.yeg ram]))
    |-  ^+  +>.^$
    ?~  gey  +>.^$
    $(gey t.gey, myz myz:^$(bus q.i.gey, +> (descend p.i.gey)))
  ::

XX document

++rm-r

  ++  rm-r                                              ::  rm -r
    |-  ^+  +
    =.  +  ?~(q.ank + (push-change %del q.u.q.ank))
    =+  dyr=(~(tap by r.ank) ~)
    |-  ^+  +.^$
    ?~  dyr  +.^$
    =.  +.^$  rm-r:(descend p.i.dyr)
    $(dyr t.dyr)
  ::

XX document

++drum

  ++  drum                                              ::  apply effect
    |=  [pax=path mis=miso]                             ::  XX unused (++dune)
    ^+  +>
    ?^  pax
      update-hash:(ascend:$(pax t.pax, +> (descend i.pax)) i.pax ank)
    ~|  %clay-fail
    ?-    -.mis
        %del
      ?>  &(?=(^ q.ank) =(q.u.q.ank p.mis))
      +>.$(p.ank (mix p.u.q.ank p.ank), q.ank ~)
    ::
        %ins
      ?>  ?=(~ q.ank)
      =+  sam=(sham p.mis)
      +>.$(p.ank (mix sam p.ank), q.ank [~ sam p.mis])
    ::
        %mut
      ?>  ?=(^ q.ank)
      =+  nex=(lump p.mis q.u.q.ank)
      =+  sam=(sham nex)
      +>.$(p.ank :(mix sam p.u.q.ank p.ank), q.ank [~ sam nex])
    ==
  ::

XX document

++dune

  ++  dune                                              ::  apply
    |-  ^+  +                                           ::  XX unused (++durn)
    ?~  myz  +
    =>  .(+ (drum p.i.myz q.i.myz))
    $(myz ?>(?=(^ myz) t.myz))
  ::

XX document

++durn

  ++  durn                                              ::  apply forward
    |=  nyp=soba                                        ::  XX unused
    ^+  +>
    ?:  =([0 0] p.nyp)
      dune(myz q.nyp)
    =>  ?:  =(p.ank p.p.nyp)  .
        ~&  [%durn-in-wrong p.ank p.p.nyp]
        .
    =.  +>  dune(myz q.nyp)
    =>  ?:  =(p.ank q.p.nyp)  .
        ~&  [%durn-out-wrong p.ank q.p.nyp]
        .
    +>
  --

XX document