prooftree.1

.\" groff -man -Tascii prooftree.1
.\"
.TH PROOFTREE 1 "April 2020" PROOFTREE "User Manuals"
.SH NAME
prooftree \- proof-tree display for Proof General
.SH SYNOPSIS
.B prooftree \fR[\fIOptions...\fR]
.SH DESCRIPTION
.\" ============= paragraph general purpose ===================================
.B Prooftree
visualizes proof trees during proof development with 
.B Proof General\fR. 
Currently it only works for \fBCoq\fR, though adding
support for other proof assistants should be relatively easy.
.\" ==========================================================================
.P
To start a proof-tree display, hit the 
.B Prooftree
icon in the 
.B Proof General
tool-bar or select the menu entry
.I Proof-General
-> 
.I Start/Stop Prooftree
or type
.I C-c C-d
(which runs
.I proof-tree-external-display-toggle\fR).
Inside a proof, this will immediately start a proof-tree display
for the current proof. Outside a proof, 
.B Proof General
remembers to start the proof-tree display for the next proof.
.\" ==========================================================================
.P
Under normal circumstances
.B Prooftree
is started by 
.B Proof General
as an
.B Emacs
subprocess. The user interacts with 
.B Prooftree
only through the graphical user interface. A substantial part of
the proof-tree visualization task is done by
.B Proof General\fR.
Therefore not only the 
.B Prooftree
command line arguments but also other aspects can only be
configured inside 
.B Proof General\fR,
see 
.B Proof General Customization
below.
.\"
.\" ==========================================================================
.\" ================ Options =================================================
.\" ==========================================================================
.\"
.SH OPTIONS
.\" ======================================= -help ============================
.IP "-help"
Print synopsis and exit.
.\" ======================================= -config ==========================
.IP "-config"
Open the configuration dialog on startup (if you want to change
the configuration without starting 
.B Proof General\fR).
.\" ======================================= -geometry ========================
.IP "-geometry \fIspec\fR"
Sets the X geometry of the main window.
.I spec
is a standard X geometry string in the form 
\fIxpos\fRx\fIypos\fR[+\fIxoff\fR[+\fIyoff\fR]].
.\" ======================================= -tee =============================
.IP "-tee \fIfile\fR"
Write all input to
.I file
(usually for debugging purposes).
.\" ======================================= -debug ===========================
.IP "-debug"
Provide more details on errors.
.\" ======================================= -help-dialog =====================
.IP "-help-dialog"
Open the help dialog on startup. Mainly useful for proofreading
the help text.
.\" ======================================= -test-coq-evar-parser ============
.IP "-test-coq-evar-parser \fIdata\fR"
Call the
.B Coq
evar parser on
.I data\fR,
pretty print the result and exit. Useful for debugging the evar
parser only.
.\"
.\" ==========================================================================
.\" ================ Main Window =============================================
.\" ==========================================================================
.\"
.SH MAIN PROOF DISPLAY
.B Prooftree
opens one window for each proof that it is requested to display.
This window contains the proof-tree graph and a small display for
sequents and proof commands. 
.\" ==========================================================================
.SS Colors
The branches in the proof-tree graph are colored
according to their state. 
.B Prooftree
distinguishes between the following states.
.IP "current (blue by default)"
The current branch is the branch from the root of the proof tree
to the current goal.
.IP "unproven (default foreground color)"
A branch is unproven if it contains open proof goals.
.IP "proved incomplete (cyan by default)"
An incompletely proved branch has its proof finished, but some of
the existential variables that have been introduced in this
branch are not (yet) instantiated.
.IP "proved partially (dark green by default)"
In a partially proved branch all existential variables of the
branch itself are instantiated, but some of those instantiations
contain existential variables from other branches
that are not (yet) instantiated.
.IP "proved complete (green by default)"
A branch is proved complete if all its existential variables are
instantiated with terms that themselves do not contain any
existential variables.
.IP "cheated (red by default)"
A cheated branch contains a cheating proof command, such as 
.I admit\f.
.P
The colors as well as many other
.B Prooftree
parameters can be changed in the 
.B Prooftree Configuration Dialog
(see below). 
.\" ==========================================================================
.SS Navigation
When the proof tree grows large one can navigate by a variety of
means. In addition to scroll bars and the usual keys one can move
the proof tree by dragging with mouse button 1 pressed. By
default, dragging moves the viewport (i.e., the proof tree
underneath moves in the opposite direction). After setting a
negative value for 
.I Drag acceleration 
in the 
.B Prooftree Configuration Dialog\fR,
dragging will move the proof tree instead (i.e, the proof tree
moves in the same direction as the mouse).
.\" ==========================================================================
.SS Sequent Display
The sequent display below the proof tree normally shows the
ancestor sequent of the current goal. With a single left mouse
click one can display any goal or proof command in the sequent
display. A single click outside the proof tree will switch back
to default behavior. The initial size of the sequent display can
be set in the
.B Prooftree Configuration Dialog\fR.
A value of 0 hides the sequent display.
.\" ==========================================================================
.SS Tool Tips
Abbreviated proof commands and sequents are shown in full as
tool tips when the mouse pointer rests over them. Both, the tool
tips for abbreviated proof commands and for sequents can be
independently switched off in the
.B Prooftree Configuration Dialog\fR.
The length at which proof commands are abbreviated can be
configured as well.
.\" ==========================================================================
.SS Additional Displays
A double click or a shift-click displays any goal or proof
command in an additional window. These additional windows are
automatically updated, for instance, if an existential variable
is instantiated. For additional sequent displays one can browse
the instantiation history of the sequent using the forward and
backward buttons. These additional windows can be
.I detached
from the proof tree. A detached display is neither automatically
updated nor automatically deleted.
.\" ==========================================================================
.SS Existential Variables
.B Prooftree
keeps track of existential variables, whether they have been
instantiated and whether they depend on some other, not (yet)
instantiated existential. It uses different colors for proved
branches that created currently not instantiated existential
variables and branches that only depend on some not instantiated
existential created in different branches.
The list of currently not (yet) instantiated existential
variables is appended to proof commands and sequents in tool-tips
and the other displays.
.\" ==========================================================================
.P
The
.B Existential Variable Dialog
displays a table with all existential variables of the current
proof and their dependencies. Each line of the table contains a
button that marks the proof command that introduced this variable
(with yellow background, by default) and, if present, the proof
command that instantiated this variable (with orange background,
by default). 
.\" ==========================================================================
.SS Main Menu
The
.I Menu
button displays the main menu. The 
.I Clone
item clones the current proof tree in an additional window. This
additional window continues to display a snapshot of the cloned
proof tree, no matter what happens with the original proof.
.\" ==========================================================================
.P
The 
.I Show current
and
.I Show selected
items move the viewport of the proof tree such that the current
proof goal, or, respectively, the selected node will be visible
(if they exist).
.\" ==========================================================================
.P
The
.I Exit
item terminates 
.B Prooftree
and closes all proof-tree displays.
.\" ==========================================================================
.P
The remaining four items display, respectively, the
.B Existential Variable Dialog\fR,
the
.B Prooftree Configuration Dialog\fR,
and the 
.B Help
and 
.B About
windows.
.\" ==========================================================================
.SS Context Menu
A right click displays the 
.I Context Menu\fR,
which contains additional items.
.\" ==========================================================================
.P
The item
.I Undo to point
is active over sequent nodes in the proof tree. There, it sends an
retract or undo request to Proof General that retracts the
scripting buffer up to that sequent.
.\" ==========================================================================
.P
The items
.I Insert command
and
.I Insert subproof
are active over proof commands. They sent, respectively, the
selected proof command or all proof commands in the selected
subtree, to Proof General, which inserts them at point. 
.\"
.\" ==========================================================================
.\" ================ Configuration ===========================================
.\" ==========================================================================
.\"
.SH CONFIGURATION
.SS Prooftree Configuration Dialog
The configuration dialog permits to change fonts, colors, layout
parameters for proof tree drawing, to configure tool tips,
initial window sizes and some other points. Changes in the
configuration dialog take immediate effect.
The 
.I Save 
button stores the current configuration (as marshaled 
.B OCaml
record) in 
.I ~/.prooftree\fR,
which will overwrite the built-in default configuration for the
following 
.B Prooftree
runs. The 
.I Revert
button loads and applies the saved configuration.
The
.I Cancel
and
.I OK
buttons close the dialog, but
.I Cancel
additionally resets the configuration to the state before the
start of the dialog. To avoid opening partial file names, the
.I Log Proof General input
check box is deactivated when typing the log file name.
.\" ==========================================================================
.SS Proof General Customization
The location of the 
.B Prooftree
executable and the command line arguments are in the
customization group
.I proof-tree\fR.
Prover specific points, such as the regular expressions for
navigation and cheating commands are in the customization group
.I proof-tree-internals\fR.
To visit a customization group, type 
.I M-x customize-group
followed by the name of the customization group inside 
.B Proof General\fR.
.\"
.\" ==========================================================================
.\" ================ Limitations =============================================
.\" ==========================================================================
.\"
.SH LIMITATIONS
In additional sequent displays, the information about existential
variables is only shown for the latest version of the sequent and
not for older versions in the instantiation history.
.\" ==========================================================================
.P
The synchronization between Proof General and Prooftree is not
perfect. There are a few race conditions which are unlikely to occur
during interactive proof development but can be triggered by asserting
larger parts of a proof or by very quick user actions.
.IP \(bu
In a situation, where a goal contains an existential variable, this
variable is instantiated (in different branch of the proof), and the
goal is shelved and quickly unshelved, it might happen that the
updated sequent text (containing the instantiating of the existential
variable) is associated with the unshelved version of the goal.
.IP \(bu
Spawned subgoals and the instantiating of existential variables cause
asynchronous update-sequent messages sent to
.B Prooftree\fR.
When quickly retracting portions of the proof, the corresponding undo
message might overtake same update-sequent messages and thereby
confuse
.B Prooftree\fR.
.\"
.\" ==========================================================================
.\" ================ Prerequisites ===========================================
.\" ==========================================================================
.\"
.SH PREREQUISITES
This version of
.B Prooftree
requires
.B Coq
8.11 or better
and 
.B Proof General
from March 2021 or later.
.\"
.\" ==========================================================================
.\" ================ Files ===================================================
.\" ==========================================================================
.\"
.SH FILES
.IP "~/.prooftree"
Saved
.B Prooftree
configuration. Is loaded at application start-up for overwriting
the built-in default configuration. Must contain a marshaled
.B OCaml
configuration record.
.\"
.\" ==========================================================================
.\" ================ SEE ALSO ================================================
.\" ==========================================================================
.\"
.SH SEE ALSO
.TP
The \fBProoftree\fR web page, \fIhttp://askra.de/software/prooftree/\fR

.TP
The \fBProof General Adapting Manual\fR
contains now partially outdated information about adapting 
.B Prooftree
for a new proof assistant (see
.I https://proofgeneral.github.io/doc/master/adaptingman/\fR).
.\"
.\" ==========================================================================
.\" ================ History =================================================
.\" ==========================================================================
.\"
.SH HISTORY
.B Prooftree
was developed in 2011 to help to keep orientation in larger
.B Coq
proofs. The first versions required patches for
.B Coq\fR.
After a meeting with the
.B Coq
development team at the third
.B Coq
workshop in Nijmegen, the Netherlands, in 2011, Arnaud Spiwack
added the necessary support for
.B Prooftree
to
.B Coq
and
.B Prooftree
version 0.8 was the first version that worked with
.B Coq
8.4beta and the
.B Proof General
development version. 
.\" ==========================================================================
.P
The user friendly names for existential variables, introduced in
.B Coq
8.6 broke many
.B Prooftree
features for existential variables and the removal of the
.I Show Goal "id"
command in
.B Coq
8.7 broke
.B Prooftree
completely. In 2019, Jim Fehrle added the necessary support for
.B Prooftree
again to
.B Coq
8.11. The existential variable printout and the
.I Show Goal
command were slightly generalized, making it possible to simplify
the proof tree code in
.B Proof General
quite a bit.
.\"
.\" ==========================================================================
.\" ================ Credits =================================================
.\" ==========================================================================
.\"
.SH CREDITS
.B Prooftree
has been inspired by the proof tree display of
.B PVS\fR.
.\"
.\" ==========================================================================
.\" ================ Author ==================================================
.\" ==========================================================================
.\"
.SH AUTHOR
Hendrik Tews <prooftree at askra.de>