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Subject: A ton of marker entry in buffer-und-list
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--Apple-Mail=_6FFD4590-9D66-4134-A074-D2DA8DFD4244
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I=E2=80=99ve been playing around with undo recently. I used =
primitive-undo to undo some entries in the buffer-undo-list, and a ton =
of (#marker . -1) was added to the buffer-undo-list:

(nil
 ("a" . 27)
 (#<marker at 27 in a> . -1)
 (#<marker at 27 in a> . -1)
 (#<marker at 27 in a> . -1)
 (#<marker at 27 in a> . -1)
 (#<marker at 27 in a> . -1)
 (#<marker at 27 in a> . -1)
 (#<marker at 27 in a> . -1)
 (#<marker at 27 in a> . -1)
 (#<marker at 27 in a> . -1)
 (#<marker at 27 in a> . -1)
 (#<marker at 27 in a> . -1)
 (#<marker at 27 in a> . -1)
 (#<marker at 27 in a> . -1)
 (#<marker at 27 in a> . -1)
 (#<marker at 27 in a> . -1)
 (#<marker at 27 in a> . -1)
 (#<marker at 27 in a> . -1)
 (#<marker at 27 in a> . -1)
 (#<marker at 27 in a> . -1)
 (#<marker at 27 in a> . -1)
 (#<marker at 27 in a> . -1)
 (#<marker at 27 in a> . -1)
 (#<marker at 27 in a> . -1)
 (#<marker at 27 in a> . -1)
 (#<marker at 27 in a> . -1)
 (#<marker at 27 in a> . -1)
 (#<marker at 27 in a> . -1)
 (#<marker at 27 in a> . -1)
 (#<marker at 27 in a> . -1)
 (#<marker at 27 in a> . -1)
 (#<marker at 27 in a> . -1)
 (#<marker at 27 in a> . -1)
 (#<marker at 27 in a> . -1)
 (#<marker at 27 in a> . -1)
 (#<marker at 27 in a> . -1)

=E2=80=A6 hundreds of this.

Any idea of what is happening? What is this marker?

I don=E2=80=99t expect anyone to look at my code, but if you want to see =
it, here it is:


--Apple-Mail=_6FFD4590-9D66-4134-A074-D2DA8DFD4244
Content-Disposition: attachment;
	filename=vundo.el
Content-Type: application/octet-stream;
	x-unix-mode=0644;
	name="vundo.el"
Content-Transfer-Encoding: quoted-printable

;;;=20vundo.el=20---=20Visual=20undo=20tree=20=20=20=20=20=20-*-=20=
lexical-binding:=20t;=20-*-=0A=0A;;=20Author:=20Yuan=20Fu=20=
<casouri@gmail.com>=0A=0A;;;=20This=20file=20is=20NOT=20part=20of=20GNU=20=
Emacs=0A=0A;;;=20Commentary:=0A;;=0A=0A;;;=20Code:=0A;;=0A=0A(require=20=
'pcase)=0A(require=20'cl-lib)=0A(require=20'seq)=0A=0A(defun=20=
vundo--setup-test-buffer=20()=0A=20=20"Setup=20and=20pop=20a=20testing=20=
buffer.=0ATYPE=20is=20the=20type=20of=20buffer=20you=20want."=0A=20=20=
(interactive)=0A=20=20(let=20((buf=20(get-buffer=20"*vundo-test*")))=0A=20=
=20=20=20(if=20buf=20(kill-buffer=20buf))=0A=20=20=20=20(setq=20buf=20=
(get-buffer-create=20"*vundo-test*"))=0A=20=20=20=20(pop-to-buffer=20=
buf)))=0A=0A;;;=20Undo=20list=20to=20mod=20list=0A=0A(cl-defstruct=20=
vundo-m=0A=20=20"A=20modification=20in=20undo=20history.=0AThis=20object=20=
serves=20two=20purpose:=20it=20represents=20a=20modification=20in=0Aundo=20=
history,=20and=20it=20also=20represents=20the=20buffer=20state=20after=20=
the=0Amodification."=0A=20=20(idx=0A=20=20=20nil=0A=20=20=20:type=20=
integer=0A=20=20=20:documentation=20"The=20index=20of=20this=20=
modification=20in=20history.")=0A=20=20(children=0A=20=20=20nil=0A=20=20=20=
:type=20proper-list=0A=20=20=20:documentation=20"Children=20in=20tree.")=0A=
=20=20(parent=0A=20=20=20nil=0A=20=20=20:type=20vundo-m=0A=20=20=20=
:documentation=20"Parent=20in=20tree.")=0A=20=20(prev-eqv=0A=20=20=20nil=0A=
=20=20=20:type=20vundo-m=0A=20=20=20:documentation=20"The=20previous=20=
equivalent=20state.")=0A=20=20(next-eqv=0A=20=20=20nil=0A=20=20=20:type=20=
vundo-m=0A=20=20=20:documentation=20"The=20next=20equivalent=20state.")=0A=
=20=20(undo-list=0A=20=20=20nil=0A=20=20=20:type=20cons=0A=20=20=20=
:documentation=20"The=20undo-list=20at=20this=20modification.")=0A=20=20=
(point=0A=20=20=20nil=0A=20=20=20:type=20integer=0A=20=20=20=
:documentation=20"Marks=20the=20text=20node=20in=20the=20vundo=20buffer=20=
if=20drawn."))=0A=0A(defun=20vundo--mod-list-from=20(undo-list=20=
&optional=20n=20mod-list)=0A=20=20"Generate=20and=20return=20a=20=
modification=20list=20from=20UNDO-LIST.=0AIf=20N=20non-nil,=20only=20=
look=20at=20the=20first=20N=20entries=20in=20UNDO-LIST.=0AIf=20MOD-LIST=20=
non-nil,=20extend=20on=20MOD-LIST."=0A=20=20(let=20((bound=20(or=20n=20=
(length=20undo-list)))=0A=20=20=20=20=20=20=20=20(uidx=200)=0A=20=20=20=20=
=20=20=20=20(mod-list=20(or=20mod-list=20(list=20(make-vundo-m))))=0A=20=20=
=20=20=20=20=20=20new-mlist)=0A=20=20=20=20(while=20(and=20(consp=20=
undo-list)=20(<=20uidx=20bound))=0A=20=20=20=20=20=20;;=20Skip=20leading=20=
nils.=0A=20=20=20=20=20=20(while=20(and=20(<=20uidx=20bound)=20(null=20=
(nth=20uidx=20undo-list)))=0A=20=20=20=20=20=20=20=20(cl-incf=20uidx))=0A=
=20=20=20=20=20=20;;=20Add=20modification.=0A=20=20=20=20=20=20(if=20(<=20=
uidx=20bound)=0A=20=20=20=20=20=20=20=20=20=20(push=20(make-vundo-m=20=
:undo-list=20(nthcdr=20uidx=20undo-list))=0A=20=20=20=20=20=20=20=20=20=20=
=20=20=20=20=20=20new-mlist))=0A=20=20=20=20=20=20;;=20Skip=20through=20=
the=20content=20of=20this=20modification.=0A=20=20=20=20=20=20(while=20=
(nth=20uidx=20undo-list)=0A=20=20=20=20=20=20=20=20(cl-incf=20uidx)))=0A=20=
=20=20=20(append=20mod-list=20new-mlist)))=0A=0A(defun=20=
vundo--update-mapping=20(mod-list=20&optional=20hash-table=20n)=0A=20=20=
"Update=20each=20modification=20in=20MOD-LIST.=0AAdd=20:idx=20for=20each=20=
modification,=20map=20:undo-list=20back=20to=20each=0Amodification=20in=20=
HASH-TABLE.=20If=20N=20non-nil,=20start=20from=20the=20Nth=0A=
modification=20in=20MOD-LIST.=20Return=20HASH-TABLE."=0A=20=20(let=20=
((hash-table=20(or=20hash-table=0A=20=20=20=20=20=20=20=20=20=20=20=20=20=
=20=20=20=20=20=20=20=20=20=20=20(make-hash-table=0A=20=20=20=20=20=20=20=
=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20:test=20#'eq=20=
:weakness=20t=20:size=20200))))=0A=20=20=20=20(cl-loop=20for=20mod=20in=20=
(nthcdr=20(or=20n=200)=20mod-list)=0A=20=20=20=20=20=20=20=20=20=20=20=20=
=20for=20midx=20=3D=20(or=20n=200)=20then=20(1+=20midx)=0A=20=20=20=20=20=
=20=20=20=20=20=20=20=20do=20(cl-assert=20(null=20(vundo-m-idx=20mod)))=0A=
=20=20=20=20=20=20=20=20=20=20=20=20=20do=20(cl-assert=20(null=20=
(gethash=20(vundo-m-undo-list=20mod)=0A=20=20=20=20=20=20=20=20=20=20=20=20=
=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=
=20=20=20=20=20hash-table)))=0A=20=20=20=20=20=20=20=20=20=20=20=20=20do=20=
(setf=20(vundo-m-idx=20mod)=20midx)=0A=20=20=20=20=20=20=20=20=20=20=20=20=
=20do=20(puthash=20(vundo-m-undo-list=20mod)=20mod=20hash-table))=0A=20=20=
=20=20hash-table))=0A=0A;;=20(setq=20lst=20'(6=205=204=20nil=203=202=20=
1))=0A=0A;;=20(setq=20con=20(vundo--mod-list-from=20lst))=0A;;=20(setq=20=
mlist=20(car=20con))=0A;;=20(setq=20hash=20(cdr=20con))=0A=0A;;=20(setq=20=
newlst=20(append=20'(9=208=207=20nil)=20lst))=0A;;=20(setq=20ncon=20=
(vundo--mod-list-incr=20newlst=20mlist=20hash))=0A;;=20(setq=20nmlist=20=
(car=20ncon))=0A;;=20(setq=20nhash=20(cdr=20ncon))=0A=0A;;=20(setq=20=
nnlst=20(nthcdr=204=20lst))=0A;;=20(setq=20nncon=20(vundo--mod-list-incr=20=
nnlst=20mlist=20hash))=0A;;=20(setq=20nnlist=20(car=20nncon))=0A;;=20=
(setq=20nhash=20(cdr=20ncon))=0A=0A=0A;;;=20Mod=20list=20to=20eqv=20list=0A=
=0A(defun=20vundo--eqv-list-of=20(mod)=0A=20=20"Return=20all=20the=20=
modifications=20equivalent=20to=20MOD."=0A=20=20(while=20=
(vundo-m-prev-eqv=20mod)=0A=20=20=20=20(cl-assert=20(not=20(eq=20mod=20=
(vundo-m-prev-eqv=20mod))))=0A=20=20=20=20(setq=20mod=20=
(vundo-m-prev-eqv=20mod)))=0A=20=20;;=20At=20the=20first=20mod=20in=20=
the=20equiv=20chain.=0A=20=20(let=20((eqv-list=20(list=20mod)))=0A=20=20=20=
=20(while=20(vundo-m-next-eqv=20mod)=0A=20=20=20=20=20=20(cl-assert=20=
(not=20(eq=20mod=20(vundo-m-next-eqv=20mod))))=0A=20=20=20=20=20=20(setq=20=
mod=20(vundo-m-next-eqv=20mod))=0A=20=20=20=20=20=20(push=20mod=20=
eqv-list))=0A=20=20=20=20(reverse=20eqv-list)))=0A=0A(defun=20=
vundo--eqv-merge=20(mlist)=0A=20=20"Connect=20modifications=20in=20MLIST=20=
to=20be=20in=20the=20same=20equivalence=20list.=0AOrder=20is=20=
reserved."=0A=20=20(cl-loop=20for=20idx=20from=200=20to=20(1-=20(length=20=
mlist))=0A=20=20=20=20=20=20=20=20=20=20=20for=20this=20=3D=20(nth=20idx=20=
mlist)=0A=20=20=20=20=20=20=20=20=20=20=20for=20next=20=3D=20(nth=20(1+=20=
idx)=20mlist)=0A=20=20=20=20=20=20=20=20=20=20=20for=20prev=20=3D=20nil=20=
then=20(nth=20(1-=20idx)=20mlist)=0A=20=20=20=20=20=20=20=20=20=20=20do=20=
(setf=20(vundo-m-prev-eqv=20this)=20prev)=0A=20=20=20=20=20=20=20=20=20=20=
=20do=20(setf=20(vundo-m-next-eqv=20this)=20next)))=0A=0A(defun=20=
vundo--sort-mod=20(mlist=20&optional=20reverse)=0A=20=20"Return=20sorted=20=
modifications=20in=20MLIST=20by=20their=20idx...=0A...in=20ascending=20=
order.=20If=20REVERSE=20non-nil,=20sort=20in=20descending=0Aorder."=0A=20=
=20(seq-sort=20(if=20reverse=0A=20=20=20=20=20=20=20=20=20=20=20=20=20=20=
=20=20(lambda=20(m1=20m2)=0A=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=
=20=20=20(>=20(vundo-m-idx=20m1)=20(vundo-m-idx=20m2)))=0A=20=20=20=20=20=
=20=20=20=20=20=20=20=20=20(lambda=20(m1=20m2)=0A=20=20=20=20=20=20=20=20=
=20=20=20=20=20=20=20=20(<=20(vundo-m-idx=20m1)=20(vundo-m-idx=20m2))))=0A=
=20=20=20=20=20=20=20=20=20=20=20=20mlist))=0A=0A(defun=20=
vundo--eqv-merge-mod=20(m1=20m2)=0A=20=20"Put=20M1=20and=20M2=20into=20=
the=20same=20equivalence=20list."=0A=20=20(let=20((l1=20=
(vundo--eqv-list-of=20m1))=0A=20=20=20=20=20=20=20=20(l2=20=
(vundo--eqv-list-of=20m2)))=0A=20=20=20=20(vundo--eqv-merge=20=
(vundo--sort-mod=20(cl-union=20l1=20l2)))))=0A=0A(defun=20=
vundo--build-tree=20(mod-list=20mod-hash=20&optional=20from)=0A=20=20=
"Connect=20equivalent=20modifications=20and=20build=20the=20tree=20in=20=
MOD-LIST.=0AMOD-HASH=20maps=20undo-lists=20to=20modifications.=0AIf=20=
FROM=20non-nil,=20build=20from=20FORM-th=20modification=20in=20=
MOD-LIST."=0A=20=20(cl-loop=0A=20=20=20for=20m=20from=20(or=20from=200)=20=
to=20(1-=20(length=20mod-list))=0A=20=20=20for=20mod=20=3D=20(nth=20m=20=
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'vundo)=0A=0A;;;=20vundo.el=20ends=20here=0A=

--Apple-Mail=_6FFD4590-9D66-4134-A074-D2DA8DFD4244
Content-Transfer-Encoding: quoted-printable
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The idea is to display an undo-tree and move between nodes with f/b/n/p. =
You can enable it with M-x vundo RET.

Yuan



--Apple-Mail=_6FFD4590-9D66-4134-A074-D2DA8DFD4244--