(*:wrap=hard:maxLineLen=78:*)
theory JEdit
imports Base
begin
chapter {* Introduction *}
section {* Concepts and terminology *}
text {* Isabelle/jEdit is a Prover IDE that integrates \emph{parallel
proof checking} \cite{Wenzel:2009,Wenzel:2013:ITP} with
\emph{asynchronous user interaction}
\cite{Wenzel:2010,Wenzel:2012:UITP-EPTCS}, based on a
document-oriented approach to \emph{continuous proof processing}
\cite{Wenzel:2011:CICM,Wenzel:2012}. Many concepts and system
components are fit together in order to make this work. The main
building blocks are as follows.
\begin{description}
\item [PIDE] is a general framework for Prover IDEs based on
Isabelle/Scala. It is built around a concept of parallel and
asynchronous document processing, which is supported natively by the
parallel proof engine that is implemented in Isabelle/ML. The prover
discontinues the traditional TTY-based command loop, and supports
direct editing of formal source text with rich formal markup for GUI
rendering.
\item [Isabelle/ML] is the implementation and extension language of
Isabelle, see also \cite{isabelle-implementation}. It is integrated
into the logical context of Isabelle/Isar and allows to manipulate
logical entities directly. Arbitrary add-on tools may be implemented
for object-logics such as Isabelle/HOL.
\item [Isabelle/Scala] is the system programming language of
Isabelle. It extends the pure logical environment of Isabelle/ML
towards the ``real world'' of graphical user interfaces, text
editors, IDE frameworks, web services etc. Special infrastructure
allows to transfer algebraic datatypes and formatted text easily
between ML and Scala, using asynchronous protocol commands.
\item [jEdit] is a sophisticated text editor implemented in
Java.\footnote{@{url "http://www.jedit.org"}} It is easily extensible
by plugins written in languages that work on the JVM, e.g.\
Scala\footnote{@{url "http://www.scala-lang.org/"}}.
\item [Isabelle/jEdit] is the main example application of the PIDE
framework and the default user-interface for Isabelle. It targets
both beginners and experts. Technically, Isabelle/jEdit combines a
slightly modified version of the jEdit code base with a special
plugin for Isabelle, integrated as standalone application for the
main operating system platforms: Linux, Windows, Mac OS X.
\end{description}
The subtle differences of Isabelle/ML versus Standard ML,
Isabelle/Scala versus Scala, Isabelle/jEdit versus jEdit need to be
taken into account when discussing any of these PIDE building blocks
in public forums, mailing lists, or even scientific publications.
*}
section {* The Isabelle/jEdit Prover IDE *}
text {*
\begin{figure}[htb]
\begin{center}
\includegraphics[width=\textwidth]{isabelle-jedit}
\end{center}
\caption{The Isabelle/jEdit Prover IDE}
\label{fig:isabelle-jedit}
\end{figure}
Isabelle/jEdit (\figref{fig:isabelle-jedit}) consists of some
plugins for the well-known jEdit text editor
@{url "http://www.jedit.org"}, according to the following principles.
\begin{itemize}
\item The original jEdit look-and-feel is generally preserved,
although some default properties are changed to accommodate Isabelle
(e.g.\ the text area font).
\item Formal Isabelle/Isar text is checked asynchronously while
editing. The user is in full command of the editor, and the prover
refrains from locking portions of the buffer.
\item Prover feedback works via colors, boxes, squiggly underline,
hyperlinks, popup windows, icons, clickable output --- all based on
semantic markup produced by Isabelle in the background.
\item Using the mouse together with the modifier key @{verbatim
CONTROL} (Linux, Windows) or @{verbatim COMMAND} (Mac OS X) exposes
additional formal content via tooltips and/or hyperlinks.
\item Formal output (in popups etc.) may be explored recursively,
using the same techniques as in the editor source buffer.
\item Additional panels (e.g.\ \emph{Output}, \emph{Symbols}) are
organized by the Dockable Window Manager of jEdit, which also allows
multiple floating instances of each window class.
\item The prover process and source files are managed on the editor
side. The prover operates on timeless and stateless document
content as provided via Isabelle/Scala.
\item Plugin options of jEdit (for the \emph{Isabelle} plugin) give
access to a selection of Isabelle/Scala options and its persistent
preferences, usually with immediate effect on the prover back-end or
editor front-end.
\item The logic image of the prover session may be specified within
Isabelle/jEdit. The new image is provided automatically by the
Isabelle build tool after restart of the application.
\end{itemize}
*}
subsection {* Documentation *}
text {* Regular jEdit documentation is accessible via its @{verbatim
Help} menu or @{verbatim F1} keyboard shortcut. This includes a
full \emph{User's Guide} and \emph{Frequently Asked Questions} for
this sophisticated text editor. The same can be browsed without the
technical restrictions of the built-in Java HTML viewer here:
@{url "http://www.jedit.org/index.php?page=docs"} (potentially for a
different version of jEdit).
Most of this information about jEdit is relevant for Isabelle/jEdit
as well, but one needs to keep in mind that defaults sometimes
differ, and the official jEdit documentation does not know about the
Isabelle plugin with its special support for theory editing.
*}
subsection {* Plugins *}
text {* The \emph{Plugin Manager} of jEdit allows to augment editor
functionality by JVM modules (jars) that are provided by the central
plugin repository, which is accessible via various mirror sites.
Connecting to the plugin server infrastructure of the jEdit project
allows to update bundled plugins or to add further functionality.
This needs to be done with the usual care for such an open bazaar of
contributions. Arbitrary combinations of add-on features are apt to
cause problems. It is advisable to start with the default
configuration of Isabelle/jEdit and develop some understanding how
it is supposed to work, before loading additional plugins at a grand
scale.
\medskip The main \emph{Isabelle} plugin is an integral part of
Isabelle/jEdit and needs to remain active at all times! A few
additional plugins are bundled with Isabelle/jEdit for convenience
or out of necessity, notably \emph{Console} with its Isabelle/Scala
sub-plugin and \emph{SideKick} with some Isabelle-specific parsers
for document tree structure. The \emph{ErrorList} plugin is
required by \emph{SideKick}, but not used specifically in
Isabelle/jEdit. *}
subsection {* Options *}
text {* Both jEdit and Isabelle have distinctive management of
persistent options.
Regular jEdit options are accessible via the dialog for
\emph{Plugins / Plugin Options}, which is also accessible via
\emph{Utilities / Global Options}. Changed properties are stored in
@{file_unchecked "$ISABELLE_HOME_USER/jedit/properties"}. In
contrast, Isabelle system options are managed by Isabelle/Scala and
changed values stored in @{file_unchecked
"$ISABELLE_HOME_USER/etc/preferences"}, independently of the jEdit
properties. See also \cite{isabelle-sys}, especially the coverage
of sessions and command-line tools like @{tool build} or @{tool
options}.
Those Isabelle options that are declared as \textbf{public} are
configurable in jEdit via \emph{Plugin Options / Isabelle /
General}. Moreover, there are various options for rendering of
document content, which are configurable via \emph{Plugin Options /
Isabelle / Rendering}. Thus \emph{Plugin Options / Isabelle} in
jEdit provides a view on a subset of Isabelle system options. Note
that some of these options affect general parameters that are
relevant outside Isabelle/jEdit as well, e.g.\ @{system_option
threads} or @{system_option parallel_proofs} for the Isabelle build
tool \cite{isabelle-sys}.
\medskip All options are loaded on startup and saved on shutdown of
Isabelle/jEdit. Editing the machine-generated @{file_unchecked
"$ISABELLE_HOME_USER/jedit/properties"} or @{file_unchecked
"$ISABELLE_HOME_USER/etc/preferences"} manually while the
application is running is likely to cause surprise due to lost
update! *}
subsection {* Keymaps *}
text {* Keyboard shortcuts used to be managed as jEdit properties in
the past, but recent versions (2013) have a separate concept of
\emph{keymap} that is configurable via \emph{Global Options /
Shortcuts}. The @{verbatim imported} keymap is derived from the
initial environment of properties that is available at the first
start of the editor; afterwards the keymap file takes precedence.
This is relevant for Isabelle/jEdit due to various fine-tuning of
default properties, and additional keyboard shortcuts for Isabelle
specific functionality. Users may change their keymap later, but
need to copy Isabelle-specific key bindings manually (see also
@{file_unchecked "$ISABELLE_HOME_USER/jedit/keymaps"}). *}
subsection {* Look-and-feel *}
text {* jEdit is a Java/AWT/Swing application with some ambition to
support ``native'' look-and-feel on all platforms, within the limits
of what Oracle as Java provider and major operating system
distributors allow (see also \secref{sec:problems}).
Isabelle/jEdit enables platform-specific look-and-feel by default as
follows:
\begin{description}
\item[Linux] The platform-independent \emph{Nimbus} is used by
default.
\emph{GTK+} works under the side-condition that the overall GTK
theme is selected in a Swing-friendly way.\footnote{GTK support in
Java/Swing was once marketed aggressively by Sun, but never quite
finished, and is today (2013) lagging a bit behind further
development of Swing and GTK. The graphics rendering performance
can be worse than for other Swing look-and-feels.}
\item[Windows] Regular \emph{Windows} is used by default, but
\emph{Windows Classic} also works.
\item[Mac OS X] Regular \emph{Mac OS X} is used by default.
Moreover the bundled \emph{MacOSX} plugin provides various functions
that are expected from applications on that particular platform:
quit from menu or dock, preferences menu, drag-and-drop of text
files on the application, full-screen mode for main editor windows
etc.
\end{description}
Users may experiment with different look-and-feels, but need to keep
in mind that this extra variance of GUI functionality is unlikely to
work in arbitrary combinations. The platform-independent
\emph{Nimbus} and \emph{Metal} should always work. The historic
\emph{CDE/Motif} is better avoided.
After changing the look-and-feel in \emph{Global Options /
Appearance}, it is advisable to restart Isabelle/jEdit in order to
take full effect. *}
chapter {* Prover IDE functionality *}
section {* File-system access *}
text {* File specifications in jEdit follow various formats and
conventions according to \emph{Virtual File Systems}, which may be
also provided by additional plugins. This allows to access remote
files via the @{verbatim "http:"} protocol prefix, for example.
Isabelle/jEdit attempts to work with the file-system access model of
jEdit as far as possible. In particular, theory sources are passed
directly from the editor to the prover, without indirection via
files.
Despite the flexibility of URLs in jEdit, local files are
particularly important and are accessible without protocol prefix.
Here the path notation is that of the Java Virtual Machine on the
underlying platform. On Windows the preferred form uses
backslashes, but happens to accept Unix/POSIX forward slashes, too.
Further differences arise due to drive letters and network shares.
The Java notation for files needs to be distinguished from the one
of Isabelle, which uses POSIX notation with forward slashes on
\emph{all} platforms.\footnote{Isabelle on Windows uses Cygwin
file-system access.} Moreover, environment variables from the
Isabelle process may be used freely, e.g.\ @{file
"$ISABELLE_HOME/etc/symbols"} or @{file "$POLYML_HOME/README"}.
There are special shortcuts: @{file "~"} for @{file "$USER_HOME"}
and @{file "~~"} for @{file "$ISABELLE_HOME"}.
\medskip Since jEdit happens to support environment variables within
file specifications as well, it is natural to use similar notation
within the editor, e.g.\ in the file-browser. This does not work in
full generality, though, due to the bias of jEdit towards
platform-specific notation and of Isabelle towards POSIX. Moreover,
the Isabelle settings environment is not yet active when starting
Isabelle/jEdit via its standard application wrapper (in contrast to
@{verbatim "isabelle jedit"} run from the command line).
For convenience, Isabelle/jEdit imitates at least @{verbatim
"$ISABELLE_HOME"} and @{verbatim "$ISABELLE_HOME_USER"} within the
Java process environment, in order to allow easy access to these
important places from the editor.
Moreover note that path specifications in prover input or output
usually include formal markup that turns it into a hyperlink (see
also \secref{sec:tooltips-hyperlinks}). This allows to open the
corresponding file in the text editor, independently of the path
notation. *}
section {* Text buffers and theories \label{sec:buffers-theories} *}
text {* As regular text editor, jEdit maintains a collection of open
\emph{text buffers} to store source files; each buffer may be
associated with any number of visible \emph{text areas}. Buffers
are subject to an \emph{edit mode} that is determined from the file
type. Files with extension \texttt{.thy} are assigned to the mode
\emph{isabelle} and treated specifically.
\medskip Isabelle theory files are automatically added to the formal
document model of Isabelle/Scala, which maintains a family of
versions of all sources for the prover. The \emph{Theories} panel
provides an overview of the status of continuous checking of theory
sources. Unlike batch sessions \cite{isabelle-sys}, theory nodes
are identified by full path names; this allows to work with multiple
(disjoint) Isabelle sessions simultaneously within the same editor
session.
Certain events to open or update buffers with theory files cause
Isabelle/jEdit to resolve dependencies of \emph{theory imports}.
The system requests to load additional files into editor buffers, in
order to be included in the theory document model for further
checking. It is also possible to resolve dependencies
automatically, depending on \emph{Plugin Options / Isabelle /
General / Auto load}.
\medskip The open text area views on theory buffers define the
visible \emph{perspective} of Isabelle/jEdit. This is taken as a
hint for document processing: the prover ensures that those parts of
a theory where the user is looking are checked, while other parts
that are presently not required are ignored. The perspective is
changed by opening or closing text area windows, or scrolling within
an editor window.
The \emph{Theories} panel provides some further options to influence
the process of continuous checking: it may be switched off globally
to restrict the prover to superficial processing of command syntax.
It is also possible to indicate theory nodes as \emph{required} for
continuous checking: this means such nodes and all their imports are
always processed independently of the visibility status (if
continuous checking is enabled). Big theory libraries that are
marked as required can have significant impact on performance,
though.
\medskip Formal markup of checked theory content is turned into GUI
rendering, based on a standard repertoire known from IDEs for
programming languages: colors, icons, highlighting, squiggly
underline, tooltips, hyperlinks etc. For outer syntax of
Isabelle/Isar there is some traditional syntax-highlighting via
static keyword tables and tokenization within the editor. In
contrast, the painting of inner syntax (term language etc.)\ uses
semantic information that is reported dynamically from the logical
context. Thus the prover can provide additional markup to help the
user to understand the meaning of formal text, and to produce more
text with some add-on tools (e.g.\ information messages by automated
provers or disprovers running in the background).
*}
section {* Prover output \label{sec:prover-output} *}
text {* Prover output consists of \emph{markup} and \emph{messages}.
Both are directly attached to the corresponding positions in the
original source text, and visualized in the text area, e.g.\ as text
colours for free and bound variables, or as squiggly underline for
warnings, errors etc.\ (see also \figref{fig:output}). In the
latter case, the corresponding messages are shown by hovering with
the mouse over the highlighted text --- although in many situations
the user should already get some clue by looking at the position of
the text highlighting.
\begin{figure}[htb]
\begin{center}
\includegraphics[width=\textwidth]{output}
\end{center}
\caption{Multiple views on prover output: gutter area with icon,
text area with popup, overview area, Theories panel, Output panel}
\label{fig:output}
\end{figure}
The ``gutter area'' on the left-hand-side of the text area uses
icons to provide a summary of the messages within the adjacent
line of text. Message priorities are used to prefer errors over
warnings, warnings over information messages etc. Plain output is
ignored here.
The ``overview area'' on the right-hand-side of the text area uses
similar information to paint small rectangles for the overall status
of the whole text buffer. The graphics is scaled to fit the logical
buffer length into the given window height. Mouse clicks on the
overview area position the cursor approximately to the corresponding
line of text in the buffer. Repainting the overview in real-time
causes problems with big theories, so it is restricted to part of
the text according to \emph{Plugin Options / Isabelle / General /
Text Overview Limit} (in characters).
Another course-grained overview is provided by the \emph{Theories}
panel, but without direct correspondence to text positions. A
double-click on one of the theory entries with their status overview
opens the corresponding text buffer, without changing the cursor
position.
\medskip In addition, the \emph{Output} panel displays prover
messages that correspond to a given command, within a separate
window.
The cursor position in the presently active text area determines the
prover commands whose cumulative message output is appended and
shown in that window (in canonical order according to the processing
of the command). There are also control elements to modify the
update policy of the output wrt.\ continued editor movements. This
is particularly useful with several independent instances of the
\emph{Output} panel, which the Dockable Window Manager of jEdit can
handle conveniently.
Former users of the old TTY interaction model (e.g.\ Proof~General)
might find a separate window for prover messages familiar, but it is
important to understand that the main Prover IDE feedback happens
elsewhere. It is possible to do meaningful proof editing
efficiently, using secondary output windows only rarely.
The main purpose of the output window is to ``debug'' unclear
situations by inspecting internal state of the prover.\footnote{In
that sense, unstructured tactic scripts depend on continuous
debugging with internal state inspection.} Consequently, some
special messages for \emph{tracing} or \emph{proof state} only
appear here, and are not attached to the original source.
\medskip In any case, prover messages also contain markup that may
be explored recursively via tooltips or hyperlinks (see
\secref{sec:tooltips-hyperlinks}), or clicked directly to initiate
certain actions (see \secref{sec:auto-tools} and
\secref{sec:sledgehammer}). *}
section {* Tooltips and hyperlinks \label{sec:tooltips-hyperlinks} *}
text {* Formally processed text (prover input or output) contains rich
markup information that can be explored further by using the
@{verbatim CONTROL} modifier key on Linux and Windows, or @{verbatim
COMMAND} on Mac OS X. Hovering with the mouse while the modifier is
pressed reveals a \emph{tooltip} (grey box over the text with a
yellow popup) and/or a \emph{hyperlink} (black rectangle over the
text); see also \figref{fig:tooltip}.
\begin{figure}[htb]
\begin{center}
\includegraphics[scale=0.3]{popup1}
\end{center}
\caption{Tooltip and hyperlink for some formal entity}
\label{fig:tooltip}
\end{figure}
Tooltip popups use the same rendering principles as the main text
area, and further tooltips and/or hyperlinks may be exposed
recursively by the same mechanism; see \figref{fig:nested-tooltips}.
\begin{figure}[htb]
\begin{center}
\includegraphics[scale=0.3]{popup2}
\end{center}
\caption{Nested tooltips over formal entities}
\label{fig:nested-tooltips}
\end{figure}
The tooltip popup window provides some controls to \emph{close} or
\emph{detach} the window, turning it into a separate \emph{Info}
window managed by jEdit. The @{verbatim ESCAPE} key closes
\emph{all} popups, which is particularly relevant when nested
tooltips are stacking up.
\medskip A black rectangle in the text indicates a hyperlink that
may be followed by a mouse click (while the @{verbatim CONTROL} or
@{verbatim COMMAND} modifier key is still pressed). Presently
(Isabelle2013-2) there is no systematic navigation within the
editor to return to the original location.
Also note that the link target may be a file that is itself not
subject to formal document processing of the editor session and thus
prevents further exploration: the chain of hyperlinks may end in
some source file of the underlying logic image, or within the
Isabelle/ML bootstrap sources of Isabelle/Pure. *}
section {* Text completion \label{sec:completion} *}
text {* \paragraph{Completion tables} are determined statically from
the ``outer syntax'' of the underlying edit mode (for theory files
this is the syntax of Isar commands), and specifications of Isabelle
symbols (see also \secref{sec:symbols}).
Symbols are completed in backslashed forms, e.g.\ @{verbatim
"\\"}@{verbatim "forall"} or @{verbatim "\<forall>"} that both produce the
Isabelle symbol @{text "\<forall>"} in its Unicode rendering.\footnote{The
extra backslash avoids overlap with keywords of the buffer syntax,
and allows to produce Isabelle symbols robustly in most syntactic
contexts.} Alternatively, symbol abbreviations may be used as
specified in @{file "$ISABELLE_HOME/etc/symbols"}.
\paragraph{Completion popups} are required in situations of
ambiguous completion results or where explicit confirmation is
demanded before inserting completed text into the buffer.
The popup is some minimally invasive GUI component over the text
area. It interprets special keys @{verbatim TAB}, @{verbatim
ESCAPE}, @{verbatim UP}, @{verbatim DOWN}, @{verbatim PAGE_UP},
@{verbatim PAGE_DOWN}, but all other key events are passed to the
underlying text area. This allows to ignore unwanted completions
most of the time and continue typing quickly.
The meaning of special keys is as follows:
\medskip
\begin{tabular}{ll}
\textbf{key} & \textbf{action} \\\hline
@{verbatim "TAB"} & select completion \\
@{verbatim "ESCAPE"} & dismiss popup \\
@{verbatim "UP"} & move up one item \\
@{verbatim "DOWN"} & move down one item \\
@{verbatim "PAGE_UP"} & move up one page of items \\
@{verbatim "PAGE_DOWN"} & move down one page of items \\
\end{tabular}
\medskip
Movement within the popup is only active for multiple items.
Otherwise the corresponding key event retains its standard meaning
within the underlying text area.
\paragraph{Explicit completion} is triggered by the keyboard
shortcut @{verbatim "C+b"} (action @{verbatim "isabelle.complete"}).
This overrides the original jEdit binding for action @{verbatim
"complete-word"}, but the latter is used as fall-back for
non-Isabelle edit modes. It is also possible to restore the
original jEdit keyboard mapping of @{verbatim "complete-word"} via
\emph{Global Options / Shortcuts}.
Replacement text is inserted immediately into the buffer, unless
ambiguous results demand an explicit popup.
\paragraph{Implicit completion} is triggered by regular keyboard
input events during of the editing process in the main jEdit text
area (and a few additional text fields like the search criteria of
the Find panel, see \secref{sec:find}). Implicit completion depends
on on further side-conditions:
\begin{enumerate}
\item The system option @{system_option jedit_completion} needs to
be enabled (default).
\item Completion of syntax keywords requires at least 3 relevant
characters in the text.
\item The system option @{system_option jedit_completion_delay}
determines an additional delay (0.0 by default), before opening a
completion popup.
\item The system option @{system_option
jedit_completion_dismiss_delay} determines an additional delay (0.0
by default), before dismissing an earlier completion popup. A value
like 0.1 is occasionally useful to reduce the chance of loosing key
strokes when the speed of typing exceeds that of repainting GUI
components.
\item The system option @{system_option jedit_completion_immediate}
(disabled by default) controls whether replacement text should be
inserted immediately without popup. This is restricted to Isabelle
symbols and their abbreviations (\secref{sec:symbols}) --- plain
keywords always demand a popup for clarity.
\item Completion of symbol abbreviations with only one relevant
character in the text always enforces an explicit popup,
independently of @{system_option jedit_completion_immediate}.
\end{enumerate}
These completion options may be configured in \emph{Plugin Options /
Isabelle / General / Completion}. The default is quite moderate in
showing occasional popups and refraining from immediate insertion.
An additional completion delay of 0.3 seconds will make it even less
ambitious.
In contrast, more aggressive completion works via @{system_option
jedit_completion_delay}~@{verbatim "= 0.0"} and @{system_option
jedit_completion_immediate}~@{verbatim "= true"}. Thus the editing
process becomes dependent on the system guessing correctly what the
user had in mind. It requires some practice (and study of the
symbol abbreviation tables) to become productive in this advanced
mode.
In any case, unintended completions can be reverted by the regular
@{verbatim undo} operation of jEdit. When editing embedded
languages such as ML, it is better to disable either @{system_option
jedit_completion} or @{system_option jedit_completion_immediate}
temporarily. *}
section {* Isabelle symbols \label{sec:symbols} *}
text {* Isabelle sources consist of \emph{symbols} that extend plain
ASCII to allow infinitely many mathematical symbols within the
formal sources. This works without depending on particular
encodings and varying Unicode standards
\cite{Wenzel:2011:CICM}.\footnote{Raw Unicode characters within
formal sources would compromise portability and reliability in the
face of changing interpretation of special features of Unicode, such
as Combining Characters or Bi-directional Text.}
For the prover back-end, formal text consists of ASCII characters
that are grouped according to some simple rules, e.g.\ as plain
``@{verbatim a}'' or symbolic ``@{verbatim "\<alpha>"}''.
For the editor front-end, a certain subset of symbols is rendered
physically via Unicode glyphs, in order to show ``@{verbatim "\<alpha>"}''
as ``@{text "\<alpha>"}'', for example. This symbol interpretation is
specified by the Isabelle system distribution in @{file
"$ISABELLE_HOME/etc/symbols"} and may be augmented by the user in
@{file_unchecked "$ISABELLE_HOME_USER/etc/symbols"}.
The appendix of \cite{isabelle-isar-ref} gives an overview of the
standard interpretation of finitely many symbols from the infinite
collection. Uninterpreted symbols are displayed literally, e.g.\
``@{verbatim "\<foobar>"}''. Overlap of Unicode characters used in
symbol interpretation with informal ones (which might appear e.g.\
in comments) needs to be avoided! Raw Unicode characters within
prover source files should be restricted to informal parts, e.g.\ to
write text in non-latin alphabets in comments.
\medskip \paragraph{Encoding.} Technically, the Unicode view on
Isabelle symbols is an \emph{encoding} in jEdit (not in the
underlying JVM) that is called @{verbatim "UTF-8-Isabelle"}. It is
provided by the Isabelle/jEdit plugin and enabled by default for all
source files. Sometimes such defaults are reset accidentally, or
malformed UTF-8 sequences in the text force jEdit to fall back on a
different encoding like @{verbatim "ISO-8859-15"}. In that case,
verbatim ``@{verbatim "\<alpha>"}'' will be shown in the text buffer
instead of its Unicode rendering ``@{text "\<alpha>"}''. The jEdit menu
operation \emph{File / Reload with Encoding / UTF-8-Isabelle} helps
to resolve such problems, potentially after repairing malformed
parts of the text.
\medskip \paragraph{Font.} Correct rendering via Unicode requires a
font that contains glyphs for the corresponding codepoints. Most
system fonts lack that, so Isabelle/jEdit prefers its own
application font @{verbatim IsabelleText}, which ensures that
standard collection of Isabelle symbols are actually seen on the
screen (or printer).
Note that a Java/AWT/Swing application can load additional fonts
only if they are not installed on the operating system already!
Some old version of @{verbatim IsabelleText} that happens to be
provided by the operating system would prevents Isabelle/jEdit from
its bundled version. This could lead to missing glyphs (black
rectangles), when the system version of @{verbatim IsabelleText} is
older than the application version. This problem can be avoided by
refraining to ``install'' any version of @{verbatim IsabelleText} in
the first place (although it might be occasionally tempting to use
the same font in other applications).
\medskip \paragraph{Input methods.} In principle, Isabelle/jEdit
could delegate the problem to produce Isabelle symbols in their
Unicode rendering to the underlying operating system and its
\emph{input methods}. Regular jEdit also provides various ways to
work with \emph{abbreviations} to produce certain non-ASCII
characters. Since none of these standard input methods work
satisfactorily for the mathematical characters required for
Isabelle, various specific Isabelle/jEdit mechanisms are provided.
Here is a summary for practically relevant input methods for
Isabelle symbols:
\begin{enumerate}
\item The \emph{Symbols} panel with some GUI buttons to insert
certain symbols in the text buffer. There are also tooltips to
reveal the official Isabelle representation with some additional
information about \emph{symbol abbreviations} (see below).
\item Copy / paste from decoded source files: text that is rendered
as Unicode already can be re-used to produce further text. This
also works between different applications, e.g.\ Isabelle/jEdit and
some web browser or mail client, as long as the same Unicode view on
Isabelle symbols is used uniformly.
\item Copy / paste from prover output within Isabelle/jEdit. The
same principles as for text buffers apply, but note that \emph{copy}
in secondary Isabelle/jEdit windows works via the keyboard shortcut
@{verbatim "C+c"}, while jEdit menu actions always refer to the
primary text area!
\item Completion provided by Isabelle plugin (see
\secref{sec:completion}). Isabelle symbols have a canonical name
and optional abbreviations. This can be used with the text
completion mechanism of Isabelle/jEdit, to replace a prefix of the
actual symbol like @{verbatim "\<lambda>"}, or its backslashed name
@{verbatim "\\"}@{verbatim "lambda"}, or its ASCII abbreviation
@{verbatim "%"} by the Unicode rendering.
The following table is an extract of the information provided by the
standard @{file "$ISABELLE_HOME/etc/symbols"} file:
\medskip
\begin{tabular}{lll}
\textbf{symbol} & \textbf{backslashed name} & \textbf{abbreviation} \\\hline
@{text "\<lambda>"} & @{verbatim "\\lambda"} & @{verbatim "%"} \\
@{text "\<Rightarrow>"} & @{verbatim "\\Rightarrow"} & @{verbatim "=>"} \\
@{text "\<Longrightarrow>"} & @{verbatim "\\Longrightarrow"} & @{verbatim "==>"} \\[0.5ex]
@{text "\<And>"} & @{verbatim "\\And"} & @{verbatim "!!"} \\
@{text "\<equiv>"} & @{verbatim "\\equiv"} & @{verbatim "=="} \\[0.5ex]
@{text "\<forall>"} & @{verbatim "\\forall"} & @{verbatim "!"} \\
@{text "\<exists>"} & @{verbatim "\\exists"} & @{verbatim "?"} \\
@{text "\<longrightarrow>"} & @{verbatim "\\longrightarrow"} & @{verbatim "-->"} \\
@{text "\<and>"} & @{verbatim "\\and"} & @{verbatim "&"} \\
@{text "\<or>"} & @{verbatim "\\or"} & @{verbatim "|"} \\
@{text "\<not>"} & @{verbatim "\\not"} & @{verbatim "~"} \\
@{text "\<noteq>"} & @{verbatim "\\noteq"} & @{verbatim "~="} \\
@{text "\<in>"} & @{verbatim "\\in"} & @{verbatim ":"} \\
@{text "\<notin>"} & @{verbatim "\\notin"} & @{verbatim "~:"} \\
\end{tabular}
\medskip
Note that the above abbreviations refer to the input method. The
logical notation provides ASCII alternatives that often coincide,
but deviate occasionally. This occasionally causes user confusion
with very old-fashioned Isabelle source that use ASCII replacement
notation like @{verbatim "!"} or @{verbatim "ALL"} directly in the
text.
On the other hand, coincidence of symbol abbreviations with ASCII
replacement syntax syntax helps to update old theory sources via
explicit completion (see also @{verbatim "C+b"} explained in
\secref{sec:completion}).
\end{enumerate}
\paragraph{Control symbols.} There are some special control symbols
to modify the display style of a single symbol (without
nesting). Control symbols may be applied to a region of selected
text, either using the \emph{Symbols} panel or keyboard shortcuts or
jEdit actions. These editor operations produce a separate control
symbol for each symbol in the text, in order to make the whole text
appear in a certain style.
\medskip
\begin{tabular}{llll}
\textbf{style} & \textbf{symbol} & \textbf{shortcut} & \textbf{action} \\\hline
superscript & @{verbatim "\<^sup>"} & @{verbatim "C+e UP"} & @{verbatim "isabelle.control-sup"} \\
subscript & @{verbatim "\<^sub>"} & @{verbatim "C+e DOWN"} & @{verbatim "isabelle.control-sub"} \\
bold face & @{verbatim "\<^bold>"} & @{verbatim "C+e RIGHT"} & @{verbatim "isabelle.control-bold"} \\
reset & & @{verbatim "C+e LEFT"} & @{verbatim "isabelle.control-reset"} \\
\end{tabular}
\medskip
To produce a single control symbol, it is also possible to complete
on @{verbatim "\\"}@{verbatim sup}, @{verbatim "\\"}@{verbatim sub},
@{verbatim "\\"}@{verbatim bold} as for regular symbols. *}
section {* Automatically tried tools \label{sec:auto-tools} *}
text {* Continuous document processing works asynchronously in the
background. Visible document source that has been evaluated already
may get augmented by additional results of \emph{asynchronous print
functions}. The canonical example is proof state output, which is
always enabled. More heavy-weight print functions may be applied,
in order to prove or disprove parts of the formal text by other
means.
Isabelle/HOL provides various automatically tried tools that operate
on outermost goal statements (e.g.\ @{command lemma}, @{command
theorem}), independently of the state of the current proof attempt.
They work implicitly without any arguments. Results are output as
\emph{information messages}, which are indicated in the text area by
blue squiggles and a blue information sign in the gutter (see
\figref{fig:auto-tools}). The message content may be shown as for
other output (see also \secref{sec:prover-output}). Some tools
produce output with \emph{sendback} markup, which means that
clicking on certain parts of the output inserts that text into the
source in the proper place.
\begin{figure}[htb]
\begin{center}
\includegraphics[scale=0.3]{auto-tools}
\end{center}
\caption{Results of automatically tried tools}
\label{fig:auto-tools}
\end{figure}
\medskip The following Isabelle system options control the behavior
of automatically tried tools (see also the jEdit dialog window
\emph{Plugin Options / Isabelle / General / Automatically tried
tools}):
\begin{itemize}
\item @{system_option auto_methods} controls automatic use of a
combination of standard proof methods (@{method auto}, @{method
simp}, @{method blast}, etc.). This corresponds to the Isar command
@{command "try0"}.
The tool is disabled by default, since unparameterized invocation of
standard proof methods often consumes substantial CPU resources
without leading to success.
\item @{system_option auto_nitpick} controls a slightly reduced
version of @{command nitpick}, which tests for counterexamples using
first-order relational logic. See also the Nitpick manual
\cite{isabelle-nitpick}.
This tool is disabled by default, due to the extra overhead of
invoking an external Java process for each attempt to disprove a
subgoal.
\item @{system_option auto_quickcheck} controls automatic use of
@{command quickcheck}, which tests for counterexamples using a
series of assignments for free variables of a subgoal.
This tool is \emph{enabled} by default. It requires little
overhead, but is a bit weaker than @{command nitpick}.
\item @{system_option auto_sledgehammer} controls a significantly
reduced version of @{command sledgehammer}, which attempts to prove
a subgoal using external automatic provers. See also the
Sledgehammer manual \cite{isabelle-sledgehammer}.
This tool is disabled by default, due to the relatively heavy nature
of Sledgehammer.
\item @{system_option auto_solve_direct} controls automatic use of
@{command solve_direct}, which checks whether the current subgoals
can be solved directly by an existing theorem. This also helps to
detect duplicate lemmas.
This tool is \emph{enabled} by default.
\end{itemize}
Invocation of automatically tried tools is subject to some global
policies of parallel execution, which may be configured as follows:
\begin{itemize}
\item @{system_option auto_time_limit} (default 2.0) determines the
timeout (in seconds) for each tool execution.
\item @{system_option auto_time_start} (default 1.0) determines the
start delay (in seconds) for automatically tried tools, after the
main command evaluation is finished.
\end{itemize}
Each tool is submitted independently to the pool of parallel
execution tasks in Isabelle/ML, using hardwired priorities according
to its relative ``heaviness''. The main stages of evaluation and
printing of proof states take precedence, but an already running
tool is not canceled and may thus reduce reactivity of proof
document processing.
Users should experiment how the available CPU resources (number of
cores) are best invested to get additional feedback from prover in
the background, by using a selection of weaker or stronger tools.
*}
section {* Sledgehammer \label{sec:sledgehammer} *}
text {* The \emph{Sledgehammer} panel (\figref{fig:sledgehammer})
provides a view on some independent execution of the Isar command
@{command sledgehammer}, with process indicator (spinning wheel) and
GUI elements for important Sledgehammer arguments and options. Any
number of Sledgehammer panels may be active, according to the
standard policies of Dockable Window Management in jEdit. Closing
such windows also cancels the corresponding prover tasks.
\begin{figure}[htb]
\begin{center}
\includegraphics[scale=0.3]{sledgehammer}
\end{center}
\caption{An instance of the Sledgehammer panel}
\label{fig:sledgehammer}
\end{figure}
The \emph{Apply} button attaches a fresh invocation of @{command
sledgehammer} to the command where the cursor is pointing in the
text --- this should be some pending proof problem. Further buttons
like \emph{Cancel} and \emph{Locate} help to manage the running
process.
Results appear incrementally in the output window of the panel.
Proposed proof snippets are marked-up as \emph{sendback}, which
means a single mouse click inserts the text into a suitable place of
the original source. Some manual editing may be required
nonetheless, say to remove earlier proof attempts. *}
section {* Find theorems \label{sec:find} *}
text {* The \emph{Find} panel (\figref{fig:find}) provides an
independent view for the Isar command @{command find_theorems}. The
main text field accepts search criteria according to the syntax
@{syntax thmcriterium} given in \cite{isabelle-isar-ref}. Further
options of @{command find_theorems} are available via GUI elements.
\begin{figure}[htb]
\begin{center}
\includegraphics[scale=0.3]{find}
\end{center}
\caption{An instance of the Find panel}
\label{fig:find}
\end{figure}
The \emph{Apply} button attaches a fresh invocation of @{command
find_theorems} to the current context of the command where the
cursor is pointing in the text, unless an alternative theory context
(from the underlying logic image) is specified explicitly. *}
chapter {* Miscellaneous tools *}
section {* SideKick *}
text {* The \emph{SideKick} plugin of jEdit provides some general
services to display buffer structure in a tree view.
Isabelle/jEdit provides SideKick parsers for its main mode for
theory files, as well as some minor modes for the @{verbatim NEWS}
file, session @{verbatim ROOT} files, and system @{verbatim
options}.
Moreover, the special SideKick parser @{verbatim "isabelle-markup"}
provides access to the full (uninterpreted) markup tree of the PIDE
document model of the current buffer. This is occasionally useful
for informative purposes, but the amount of displayed information
might cause problems for large buffers, both for the human and the
machine.
*}
section {* Timing *}
text {* Managed evaluation of commands within PIDE documents includes
timing information, which consists of elapsed (wall-clock) time, CPU
time, and GC (garbage collection) time. Note that in a
multithreaded system it is difficult to measure execution time
precisely: elapsed time is closer to the real requirements of
runtime resources than CPU or GC time, which are both subject to
influences from the parallel environment that are outside the scope
of the current command transaction.
The \emph{Timing} panel provides an overview of cumulative command
timings for each document node. Commands with elapsed time below
the given threshold are ignored in the grand total. Nodes are
sorted according to their overall timing. For the document node
that corresponds to the current buffer, individual command timings
are shown as well. A double-click on a theory node or command moves
the editor focus to that particular source position.
It is also possible to reveal individual timing information via some
tooltip for the corresponding command keyword, using the technique
of mouse hovering with @{verbatim CONTROL}/@{verbatim COMMAND}
modifier key as explained in \secref{sec:tooltips-hyperlinks}.
Actual display of timing depends on the global option
@{system_option jedit_timing_threshold}, which can be configured in
"Plugin Options / Isabelle / General".
\medskip The \emph{Monitor} panel provides a general impression of
recent activity of the farm of worker threads in Isabelle/ML. Its
display is continuously updated according to @{system_option
editor_chart_delay}. Note that the painting of the chart takes
considerable runtime itself --- on the Java Virtual Machine that
runs Isabelle/Scala, not Isabelle/ML. Internally, the
Isabelle/Scala module @{verbatim isabelle.ML_Statistics} provides
further access to statistics of Isabelle/ML. *}
section {* Isabelle/Scala console *}
text {* The \emph{Console} plugin of jEdit manages various shells
(command interpreters), e.g.\ \emph{BeanShell}, which is the
official jEdit scripting language, and the cross-platform
\emph{System} shell. Thus the console provides similar
functionality than the special buffers @{verbatim "*scratch*"} and
@{verbatim "*shell*"} in Emacs.
Isabelle/jEdit extends the repertoire of the console by
\emph{Scala}, which is the regular Scala toplevel loop running
inside the \emph{same} JVM process as Isabelle/jEdit itself. This
means the Scala command interpreter has access to the JVM name space
and state of the running Prover IDE application: the main entry
points are @{verbatim view} (the current editor view of jEdit) and
@{verbatim PIDE} (the Isabelle/jEdit plugin object).
For example, the subsequent Scala snippet gets the PIDE document
model of the current buffer within the current editor view:
\begin{center}
@{verbatim "PIDE.document_model(view.getBuffer).get"}
\end{center}
This helps to explore Isabelle/Scala functionality interactively.
Some care is required to avoid interference with the internals of
the running application, especially in production use. *}
section {* Low-level output *}
text {* Prover output is normally shown directly in the main text area
or secondary \emph{Output} panels, as explained in
\secref{sec:prover-output}.
Beyond this, it is occasionally useful to inspect low-level output
channels via some of the following additional panels:
\begin{itemize}
\item \emph{Protocol} shows internal messages between the
Isabelle/Scala and Isabelle/ML side of the PIDE editing protocol.
Recording of messages starts with the first activation of the
corresponding dockable window; earlier messages are lost.
Actual display of protocol messages causes considerable slowdown, so
it is important to undock all \emph{Protocol} panels for production
work.
\item \emph{Raw Output} shows chunks of text from the @{verbatim
stdout} and @{verbatim stderr} channels of the prover process.
Recording of output starts with the first activation of the
corresponding dockable window; earlier output is lost.
The implicit stateful nature of physical I/O channels makes it
difficult to relate raw output to the actual command from where it
was originating. Parallel execution may add to the confusion.
Peeking at physical process I/O is only the last resort to diagnose
problems with tools that are not fully PIDE compliant.
Under normal circumstances, prover output always works via managed
message channels (corresponding to @{ML writeln}, @{ML warning},
@{ML error} etc.\ in Isabelle/ML), which are displayed by regular
means within the document model (\secref{sec:prover-output}).
\item \emph{Syslog} shows system messages that might be relevant to
diagnose problems with the startup or shutdown phase of the prover
process; this also includes raw output on @{verbatim stderr}.
A limited amount of syslog messages are buffered, independently of
the docking state of the \emph{Syslog} panel. This allows to
diagnose serious problems with Isabelle/PIDE process management,
outside of the actual protocol layer.
Under normal situations, such low-level system output can be
ignored.
\end{itemize}
*}
chapter {* Known problems and workarounds \label{sec:problems} *}
text {*
\begin{itemize}
\item \textbf{Problem:} Odd behavior of some diagnostic commands with
global side-effects, like writing a physical file.
\textbf{Workaround:} Copy / paste complete command text from
elsewhere, or discontinue continuous checking temporarily.
\item \textbf{Problem:} No way to delete document nodes from the overall
collection of theories.
\textbf{Workaround:} Ignore unused files. Restart whole
Isabelle/jEdit session in worst-case situation.
\item \textbf{Problem:} Keyboard shortcuts @{verbatim "C+PLUS"} and
@{verbatim "C+MINUS"} for adjusting the editor font size depend on
platform details and national keyboards.
\textbf{Workaround:} Rebind keys via \emph{Global Options /
Shortcuts}.
\item \textbf{Problem:} The Mac OS X keyboard shortcut @{verbatim
"COMMAND+COMMA"} for application \emph{Preferences} is in conflict
with the jEdit default shortcut for \emph{Incremental Search Bar}
(action @{verbatim "quick-search"}).
\textbf{Workaround:} Rebind key via \emph{Global Options /
Shortcuts} according to national keyboard, e.g.\ @{verbatim
"COMMAND+SLASH"} on English ones.
\item \textbf{Problem:} Mac OS X system fonts sometimes lead to
character drop-outs in the main text area.
\textbf{Workaround:} Use the default @{verbatim IsabelleText} font.
(Do not install that font on the system.)
\item \textbf{Problem:} Some Linux / X11 input methods such as IBus
tend to disrupt key event handling of Java/AWT/Swing.
\textbf{Workaround:} Do not use input methods, reset the environment
variable @{verbatim XMODIFIERS} within Isabelle settings (default in
Isabelle2013-2).
\item \textbf{Problem:} Some Linux / X11 window managers that are
not ``re-parenting'' cause problems with additional windows opened
by Java. This affects either historic or neo-minimalistic window
managers like @{verbatim awesome} or @{verbatim xmonad}.
\textbf{Workaround:} Use regular re-parenting window manager.
\item \textbf{Problem:} Recent forks of Linux / X11 window managers
and desktop environments (variants of Gnome) disrupt the handling of
menu popups and mouse positions of Java/AWT/Swing.
\textbf{Workaround:} Use mainstream versions of Linux desktops.
\item \textbf{Problem:} Full-screen mode via jEdit action @{verbatim
"toggle-full-screen"} (default shortcut @{verbatim F11}) works on
Windows, but not on Mac OS X or various Linux / X11 window managers.
\textbf{Workaround:} Use native full-screen control of the window
manager (notably on Mac OS X).
\item \textbf{Problem:} Full-screen mode and dockable windows in
\emph{floating} state may lead to confusion about window placement
(depending on platform characteristics).
\textbf{Workaround:} Avoid this combination.
\end{itemize}
*}
end