Modified section about generation of theory browsing information.
Documented new -P option.
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\chapter{Presenting theories}
\section{Generating theory browsing information} \label{sec:info}
\index{theory browsing information|bold}
Isabelle is able to generate theory browsing information, such as HTML
documents that show a theory's definition, the theorems proved in its
ML file and the relationship with its ancestors and descendants.
Besides the HTML file that is generated for every theory, Isabelle
stores links to all theories in an index file. These indexes are
themself linked with other indexes to represent the hierarchic
structure of Isabelle's logics.
In addition to the HTML files, Isabelle also generates \emph{graph}
files that represent the theory hierarchy of a logic. These graphs
can be comfortably displayed by a graph browser Java applet embedded
in the generated HTML pages. There is also a stand-alone version of
the graph browser which allows browsing theory graphs without having
to start a Web browser first. This version also includes features such
as generating {\sc PostScript} files, which are not available in the
applet version. The graph browser will be described later in this
chapter.
\medskip To generate theory browsing information for logics that are
part of the Isabelle distribution, simply append ``\texttt{-i true}''
to the \settdx{ISABELLE_USEDIR_OPTIONS} setting before making a logic.
For example, to generate browsing information for {\FOL}, first add
something like this to your Isabelle settings file:
\begin{ttbox}
ISABELLE_USEDIR_OPTIONS="-i true"
\end{ttbox}
Then \texttt{cd} into the \texttt{src/FOL} directory of the Isabelle
distribution and do \texttt{isatool make} (or even \texttt{isatool
make all}).
\medskip The directory in which to store theory browsing information
is determined by the \settdx{ISABELLE_BROWSER_INFO} setting.
The entry point to all logics is the {\tt index.html} file located in
the directory denoted by \texttt{ISABELLE_BROWSER_INFO}.
A complete HTML version of all distributed Isabelle object-logics and
examples may be accessed on the WWW at:
\begin{center}\small
\begin{tabular}{l}
\url{http://www.cl.cam.ac.uk/Research/HVG/Isabelle/library/} \\
\url{http://isabelle.in.tum.de/library/} \\
\end{tabular}
\end{center}
Of course, this is not necessarily consistent with your local version!
\medskip
To present your own theories on the WWW, simply copy the whole
\texttt{ISABELLE_BROWSER_INFO} directory to your WWW server.
When running your theories with the \texttt{usedir} utility, you can
generate browsing information by specifying the option \texttt{-i true}
on the command line, e.g.
\begin{ttbox}
isatool usedir -i true HOL my_theories
\end{ttbox}
The generated HTML files contain all theorems that were
proved in the theories' \ML{} files with {\tt qed}, {\tt qed_goal} and
{\tt qed_goalw}, or stored with {\tt bind_thm} and {\tt store_thm}.
Additionally, there is a hypertext link to the whole \ML{} file.
You can add section headings to the list of theorems by using
\begin{ttbox}\index{*use_dir}
section: string -> unit
\end{ttbox}
in a theory's ML file, which converts a plain string to a HTML heading
and inserts it before the next theorem proved or stored with one of
the above functions.
As some of Isabelle's logics are based on others (e.g. {\tt ZF}
on {\tt FOL}) and because the HTML files list a theory's
ancestors, you should not make HTML files for a logic if the HTML
files for the base logic do not exist. Otherwise some of the hypertext
links might point to non-existing documents. If the HTML files for the
base logic are located in a directory other than \texttt{ISABELLE_BROWSER_INFO}
or on a WWW server, you have to specify this directory or URL via
the \texttt{-P} option, e.g.
\begin{ttbox}
isatool usedir -i true
-P http://isabelle.in.tum.de/library/ HOL my_theories
\end{ttbox}
\section{Browsing theory graphs} \label{sec:browse}
\index{theory graph browser|bold}
The graph browser is a tool for visualizing dependency graphs of
Isabelle theories. Certain nodes of the graph (i.e.~theories) can be
grouped together in ``directories'', whose contents may be hidden,
thus enabling the user to filter out irrelevant information. The
browser is written in Java, it can be used both as a stand-alone
application and as an applet.
\subsection{Invoking the graph browser}
The stand-alone version of the graph browser is wrapped up as an
Isabelle tool called \tooldx{browser}:
\begin{ttbox}
Usage: browser [GRAPHFILE]
\end{ttbox}
When no filename is specified, the browser automatically changes to
the directory \texttt{ISABELLE_BROWSER_INFO/graph/data}.
\medskip The applet version of the browser can be invoked by opening
the {\tt index.html} file in the directory
\texttt{ISABELLE_BROWSER_INFO} from your Web browser and selecting
``version for Java capable browsers''. There is also a link to the
corresponding theory graph in every logic's {\tt index.html} file.
\subsection{Using the graph browser}
The browser's main window, which is shown in figure
\ref{browserwindow}, consists of two subwindows: In the left
subwindow, the directory tree is displayed. The graph itself is
displayed in the right subwindow.
\begin{figure}[h]
\includegraphics[width=\textwidth]{browser_screenshot}
\caption{\label{browserwindow} Browser main window}
\end{figure}
\subsubsection*{The directory tree window}
This section describes the usage of the directory browser and the
meaning of the different items in the browser window.
\begin{itemize}
\item A red arrow before a directory name indicates that the directory
is currently ``folded'', i.e.~the nodes in this directory are
collapsed to one single node. In the right subwindow, the names of
nodes corresponding to folded directories are enclosed in square
brackets and displayed in red colour.
\item A green downward arrow before a directory name indicates that
the directory is currently ``unfolded''. It can be folded by
clicking on the directory name. Clicking on the name for a second
time unfolds the directory again. Alternatively, a directory can
also be unfolded by clicking on the corresponding node in the right
subwindow.
\item Blue arrows stand before ordinary node (i.e.~theory) names. When
clicking on such a name, the graph display window focuses to the
corresponding node. Double clicking invokes a text viewer window in
which the contents of the theory file are displayed.
\end{itemize}
\subsubsection*{The graph display window}
When pointing on an ordinary node, an upward and a downward arrow is
shown. Initially, both of these arrows are green. Clicking on the
upward or downward arrow collapses all predecessor or successor nodes,
respectively. The arrow's colour then changes to red, indicating that
the predecessor or successor nodes are currently collapsed. The node
corresponding to the collapsed nodes has the name ``{\tt [....]}''. To
uncollapse the nodes again, simply click on the red arrow or on the
node with the name ``{\tt [....]}''. Similar to the directory browser,
the contents of theory files can be displayed by double clicking on
the corresponding node.
\subsubsection*{The ``File'' menu}
Please note that due to Java security restrictions this menu is not
available in the applet version. The meaning of the menu items is as
follows:
\begin{description}
\item[Open$\ldots$] Open a new graph file.
\item[Export to PostScript] Outputs the current graph in {\sc
PostScript} format, appropriately scaled to fit on one single
sheet of paper. The resulting file can printed directly.
\item[Export to EPS] Outputs the current graph in Encapsulated {\sc
PostScript} format. The resulting file can be included in other
documents.
\item[Quit] Quit the graph browser.
\end{description}
\subsection*{*Syntax of graph definition files}
A graph definition file has the following syntax:
\begin{eqnarray*}
\mbox{\it graph} & = & \{ \: \mbox{\it vertex \tt ;} \: \} ^ + \\
vertex & = & \mbox{\it vertexname} \: \mbox{\it vertexID} \: \mbox{\it dirname} \: [ \mbox{\tt +} ]
\: \mbox{\it path} \: [ \mbox{\tt <} | \mbox{\tt >} ] \: \{ \: \mbox{\it vertexID} \: \} ^ *
\end{eqnarray*}
The meaning of the items in a vertex description is as follows:
\begin{description}
\item[vertexname] The name of the vertex.
\item[vertexID] The vertex identifier. Note that there may be two
vertices with equal names, whereas identifiers must be unique.
\item[dirname] The name of the ``directory'' the vertex should be
placed in. A ``{\tt +}'' sign after {\it dirname} indicates that
the nodes in the directory are initially visible. Directories are
initially invisible by default.
\item[path] The path of the corresponding theory file. This is
specified relatively to the path of the graph definition file.
\item[List of successor/predecessor nodes] A ``{\tt <}'' sign before
the list means that successor nodes are listed, a ``{\tt >}'' sign
means that predecessor nodes are listed. If neither ``{\tt <}'' nor
``{\tt >}'' is found, the browser assumes that successor nodes are
listed.
\end{description}
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