urbit/main/lib/sole/core.hook
2015-04-14 13:38:37 -07:00

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::
:::: /hook/core/sole/lib
::
:: This file is in the public domain.
::
/? 310
/- *sole
!:
::::
::
|%
++ cs :: shared-state engine
|_ sole-share
++ abet +<
++ apply
|= ted=sole-edit
^+ +>
?- -.ted
%del +>.$(buf (weld (scag p.ted buf) (slag +(p.ted) buf)))
%ins +>.$(buf (weld (scag p.ted buf) `_buf`[q.ted (slag p.ted buf)]))
%mor |- ^+ +>.^$
?~ p.ted
+>.^$
$(p.ted t.p.ted, +>.^$ ^$(ted i.p.ted))
%nop +>.$
%set +>.$(buf p.ted)
==
::
::::
:: ++transmute: symmetric operational transformation.
::
:: for any sole state +>, obeys
::
:: =+ [x=(transmute a b) y=(transmute b a)]
:: .= (apply:(apply a) x)
:: (apply:(apply b) y)
::
++ transmute :: dex as after sin
|= [sin=sole-edit dex=sole-edit]
^- sole-edit
?: ?=(%mor -.sin)
|- ^- sole-edit
?~ p.sin dex
$(p.sin t.p.sin, dex ^$(sin i.p.sin))
::
?: ?=(%mor -.dex)
:- %mor
|- ^- (list sole-edit)
?~ p.dex ~
[^$(dex i.p.dex) $(p.dex t.p.dex)]
::
?: |(?=(%nop -.sin) ?=(%nop -.dex)) dex
?: ?=(%set -.sin) [%nop ~]
?: ?=(%set -.dex) dex
::
?- -.sin
%del
?- -.dex
%del ?: =(p.sin p.dex) [%nop ~]
?:((lth p.sin p.dex) dex(p (dec p.dex)) dex)
%ins ?:((lte p.sin p.dex) dex(p (dec p.dex)) dex)
==
::
%ins
?- -.dex
%del ?:((lte p.sin p.dex) dex(p +(p.dex)) dex)
%ins ?: =(p.sin p.dex)
?:((gth q.sin q.dex) dex dex(p +(p.dex)))
?:((lte p.sin p.dex) dex(p +(p.dex)) dex)
==
==
::
++ commit :: local change
|= ted=sole-edit
^- sole-share
abet:(apply(own.ven +(own.ven), leg [ted leg]) ted)
::
::::
:: ++inverse: inverse of change in context.
::
:: for any sole state +>, obeys
::
:: =(+> (apply:(apply a) (inverse a)))
::
++ inverse :: relative inverse
|= ted=sole-edit
^- sole-edit
=. ted ?.(?=([%mor * ~] ted) ted i.p.ted)
?- -.ted
%del [%ins p.ted (snag p.ted buf)]
%ins [%del p.ted]
%mor :- %mor
%- flop
|- ^- (list sole-edit)
?~ p.ted ~
:- ^$(ted i.p.ted)
$(p.ted t.p.ted, +>.^$ (apply i.p.ted))
%nop [%nop ~]
%set [%set buf]
==
::
++ receive :: naturalize event
|= sole-change
^- [sole-edit sole-share]
~| [ler ven]
?> &(=(his.ler his.ven) (lte own.ler own.ven))
?> |(!=(own.ler own.ven) =(haw (sham buf)) =(haw 0)) :: trust the clock
=. leg (scag (sub own.ven own.ler) leg)
:: ~? !=(own.ler own.ven) [%miss-leg leg]
=+ dat=(transmute [%mor leg] ted)
:: ~? !=(~ leg) [%transmute from/ted to/dat ~]
[dat abet:(apply(his.ven +(his.ven)) dat)]
::
++ remit :: conditional accept
|= [cal=sole-change ask=$+((list ,@c) ?)]
^- [(unit sole-change) sole-share]
=+ old=buf
=^ dat +>+<.$ (receive cal)
?: (ask buf)
[~ +>+<.$]
=^ lic +>+<.$ (transmit (inverse(buf old) dat))
[`lic +>+<.$]
::
++ transmit :: outgoing change
|= ted=sole-edit
^- [sole-change sole-share]
[[[his.ven own.ven] (sham buf) ted] (commit ted)]
::
++ transceive :: receive and invert
|= sole-change
^- [sole-edit sole-share]
=+ old=buf
=^ dat +>+<.$ (receive +<.$)
[(inverse(buf old) dat) +>+<.$]
::
++ transpose :: adjust position
|= pos=@ud
=+ dat=(transmute [%mor leg] [%ins pos `@c`0])
?> ?=(%ins -.dat)
p.dat
--
--