theory Document_Preparation
imports Base Main
begin
chapter \<open>Document preparation \label{ch:document-prep}\<close>
text \<open>Isabelle/Isar provides a simple document preparation system
based on {PDF-\LaTeX}, with support for hyperlinks and bookmarks
within that format. This allows to produce papers, books, theses
etc.\ from Isabelle theory sources.
{\LaTeX} output is generated while processing a \<^emph>\<open>session\<close> in
batch mode, as explained in the \<^emph>\<open>The Isabelle System Manual\<close>
@{cite "isabelle-system"}. The main Isabelle tools to get started with
document preparation are @{tool_ref mkroot} and @{tool_ref build}.
The classic Isabelle/HOL tutorial @{cite "isabelle-hol-book"} also
explains some aspects of theory presentation.\<close>
section \<open>Markup commands \label{sec:markup}\<close>
text \<open>
\begin{matharray}{rcl}
@{command_def "chapter"} & : & \<open>any \<rightarrow> any\<close> \\
@{command_def "section"} & : & \<open>any \<rightarrow> any\<close> \\
@{command_def "subsection"} & : & \<open>any \<rightarrow> any\<close> \\
@{command_def "subsubsection"} & : & \<open>any \<rightarrow> any\<close> \\
@{command_def "paragraph"} & : & \<open>any \<rightarrow> any\<close> \\
@{command_def "subparagraph"} & : & \<open>any \<rightarrow> any\<close> \\
@{command_def "text"} & : & \<open>any \<rightarrow> any\<close> \\
@{command_def "txt"} & : & \<open>any \<rightarrow> any\<close> \\
@{command_def "text_raw"} & : & \<open>any \<rightarrow> any\<close> \\
\end{matharray}
Markup commands provide a structured way to insert text into the
document generated from a theory. Each markup command takes a
single @{syntax text} argument, which is passed as argument to a
corresponding {\LaTeX} macro. The default macros provided by
@{file "~~/lib/texinputs/isabelle.sty"} can be redefined according
to the needs of the underlying document and {\LaTeX} styles.
Note that formal comments (\secref{sec:comments}) are similar to
markup commands, but have a different status within Isabelle/Isar
syntax.
@{rail \<open>
(@@{command chapter} | @@{command section} | @@{command subsection} |
@@{command subsubsection} | @@{command paragraph} | @@{command subparagraph} |
@@{command text} | @@{command txt} | @@{command text_raw}) @{syntax text}
\<close>}
\<^descr> @{command chapter}, @{command section}, @{command subsection} etc.\ mark
section headings within the theory source. This works in any context, even
before the initial @{command theory} command. The corresponding {\LaTeX}
macros are \<^verbatim>\<open>\isamarkupchapter\<close>, \<^verbatim>\<open>\isamarkupsection\<close>, \<^verbatim>\<open>\isamarkupsubsection\<close> etc.\
\<^descr> @{command text} and @{command txt} specify paragraphs of plain text.
This corresponds to a {\LaTeX} environment \<^verbatim>\<open>\begin{isamarkuptext}\<close> \<open>\<dots>\<close>
\<^verbatim>\<open>\end{isamarkuptext}\<close> etc.
\<^descr> @{command text_raw} is similar to @{command text}, but without
any surrounding markup environment. This allows to inject arbitrary
{\LaTeX} source into the generated document.
All text passed to any of the above markup commands may refer to formal
entities via \<^emph>\<open>document antiquotations\<close>, see also \secref{sec:antiq}.
These are interpreted in the present theory or proof context.
\<^medskip>
The proof markup commands closely resemble those for theory
specifications, but have a different formal status and produce
different {\LaTeX} macros.
\<close>
section \<open>Document antiquotations \label{sec:antiq}\<close>
text \<open>
\begin{matharray}{rcl}
@{antiquotation_def "theory"} & : & \<open>antiquotation\<close> \\
@{antiquotation_def "thm"} & : & \<open>antiquotation\<close> \\
@{antiquotation_def "lemma"} & : & \<open>antiquotation\<close> \\
@{antiquotation_def "prop"} & : & \<open>antiquotation\<close> \\
@{antiquotation_def "term"} & : & \<open>antiquotation\<close> \\
@{antiquotation_def term_type} & : & \<open>antiquotation\<close> \\
@{antiquotation_def typeof} & : & \<open>antiquotation\<close> \\
@{antiquotation_def const} & : & \<open>antiquotation\<close> \\
@{antiquotation_def abbrev} & : & \<open>antiquotation\<close> \\
@{antiquotation_def typ} & : & \<open>antiquotation\<close> \\
@{antiquotation_def type} & : & \<open>antiquotation\<close> \\
@{antiquotation_def class} & : & \<open>antiquotation\<close> \\
@{antiquotation_def "text"} & : & \<open>antiquotation\<close> \\
@{antiquotation_def goals} & : & \<open>antiquotation\<close> \\
@{antiquotation_def subgoals} & : & \<open>antiquotation\<close> \\
@{antiquotation_def prf} & : & \<open>antiquotation\<close> \\
@{antiquotation_def full_prf} & : & \<open>antiquotation\<close> \\
@{antiquotation_def ML} & : & \<open>antiquotation\<close> \\
@{antiquotation_def ML_op} & : & \<open>antiquotation\<close> \\
@{antiquotation_def ML_type} & : & \<open>antiquotation\<close> \\
@{antiquotation_def ML_structure} & : & \<open>antiquotation\<close> \\
@{antiquotation_def ML_functor} & : & \<open>antiquotation\<close> \\
@{antiquotation_def emph} & : & \<open>antiquotation\<close> \\
@{antiquotation_def bold} & : & \<open>antiquotation\<close> \\
@{antiquotation_def verbatim} & : & \<open>antiquotation\<close> \\
@{antiquotation_def "file"} & : & \<open>antiquotation\<close> \\
@{antiquotation_def "url"} & : & \<open>antiquotation\<close> \\
@{antiquotation_def "cite"} & : & \<open>antiquotation\<close> \\
@{command_def "print_antiquotations"}\<open>\<^sup>*\<close> & : & \<open>context \<rightarrow>\<close> \\
\end{matharray}
The overall content of an Isabelle/Isar theory may alternate between formal
and informal text. The main body consists of formal specification and proof
commands, interspersed with markup commands (\secref{sec:markup}) or
document comments (\secref{sec:comments}). The argument of markup commands
quotes informal text to be printed in the resulting document, but may again
refer to formal entities via \<^emph>\<open>document antiquotations\<close>.
For example, embedding \<^verbatim>\<open>@{term [show_types] "f x = a + x"}\<close>
within a text block makes
\isa{{\isacharparenleft}f{\isasymColon}{\isacharprime}a\ {\isasymRightarrow}\ {\isacharprime}a{\isacharparenright}\ {\isacharparenleft}x{\isasymColon}{\isacharprime}a{\isacharparenright}\ {\isacharequal}\ {\isacharparenleft}a{\isasymColon}{\isacharprime}a{\isacharparenright}\ {\isacharplus}\ x} appear in the final {\LaTeX} document.
Antiquotations usually spare the author tedious typing of logical entities
in full detail. Even more importantly, some degree of consistency-checking
between the main body of formal text and its informal explanation is
achieved, since terms and types appearing in antiquotations are checked
within the current theory or proof context.
\<^medskip>
Antiquotations are in general written as
\<^verbatim>\<open>@{\<close>\<open>name\<close>~\<^verbatim>\<open>[\<close>\<open>options\<close>\<^verbatim>\<open>]\<close>~\<open>arguments\<close>\<^verbatim>\<open>}\<close>. The short form
\<^verbatim>\<open>\\<close>\<^verbatim>\<open><^\<close>\<open>name\<close>\<^verbatim>\<open>>\<close>\<open>\<open>argument_content\<close>\<close> (without surrounding \<^verbatim>\<open>@{\<close>\<open>\<dots>\<close>\<^verbatim>\<open>}\<close>)
works for a single argument that is a cartouche. A cartouche without special
decoration is equivalent to \<^verbatim>\<open>\<^cartouche>\<close>\<open>\<open>argument_content\<close>\<close>, which is
equivalent to \<^verbatim>\<open>@{cartouche\<close>~\<open>\<open>argument_content\<close>\<close>\<^verbatim>\<open>}\<close>. The special name
@{antiquotation_def cartouche} is defined in the context: Isabelle/Pure
introduces that as an alias to @{antiquotation_ref text} (see below).
Consequently, \<open>\<open>foo_bar + baz \<le> bazar\<close>\<close> prints literal quasi-formal text
(unchecked). A control symbol \<^verbatim>\<open>\\<close>\<^verbatim>\<open><^\<close>\<open>name\<close>\<^verbatim>\<open>>\<close> within the body text, but
without a subsequent cartouche, is equivalent to \<^verbatim>\<open>@{\<close>\<open>name\<close>\<^verbatim>\<open>}\<close>.
\begingroup
\def\isasymcontrolstart{\isatt{\isacharbackslash\isacharless\isacharcircum}}
@{rail \<open>
@{syntax_def antiquotation}:
'@{' antiquotation_body '}' |
'\<controlstart>' @{syntax_ref name} '>' @{syntax_ref cartouche} |
@{syntax_ref cartouche}
;
options: '[' (option * ',') ']'
;
option: @{syntax name} | @{syntax name} '=' @{syntax name}
;
\<close>}
\endgroup
Note that the syntax of antiquotations may \<^emph>\<open>not\<close> include source comments
\<^verbatim>\<open>(*\<close>~\<open>\<dots>\<close>~\<^verbatim>\<open>*)\<close> nor verbatim text \<^verbatim>\<open>{*\<close>~\<open>\<dots>\<close>~\<^verbatim>\<open>*}\<close>.
%% FIXME less monolithic presentation, move to individual sections!?
@{rail \<open>
@{syntax_def antiquotation_body}:
(@@{antiquotation text} | @@{antiquotation cartouche} | @@{antiquotation theory_text})
options @{syntax text} |
@@{antiquotation theory} options @{syntax name} |
@@{antiquotation thm} options styles @{syntax thmrefs} |
@@{antiquotation lemma} options @{syntax prop} @'by' @{syntax method} @{syntax method}? |
@@{antiquotation prop} options styles @{syntax prop} |
@@{antiquotation term} options styles @{syntax term} |
@@{antiquotation (HOL) value} options styles @{syntax term} |
@@{antiquotation term_type} options styles @{syntax term} |
@@{antiquotation typeof} options styles @{syntax term} |
@@{antiquotation const} options @{syntax term} |
@@{antiquotation abbrev} options @{syntax term} |
@@{antiquotation typ} options @{syntax type} |
@@{antiquotation type} options @{syntax name} |
@@{antiquotation class} options @{syntax name}
;
@{syntax antiquotation}:
@@{antiquotation goals} options |
@@{antiquotation subgoals} options |
@@{antiquotation prf} options @{syntax thmrefs} |
@@{antiquotation full_prf} options @{syntax thmrefs} |
@@{antiquotation ML} options @{syntax text} |
@@{antiquotation ML_op} options @{syntax text} |
@@{antiquotation ML_type} options @{syntax text} |
@@{antiquotation ML_structure} options @{syntax text} |
@@{antiquotation ML_functor} options @{syntax text} |
@@{antiquotation emph} options @{syntax text} |
@@{antiquotation bold} options @{syntax text} |
@@{antiquotation verbatim} options @{syntax text} |
@@{antiquotation "file"} options @{syntax name} |
@@{antiquotation file_unchecked} options @{syntax name} |
@@{antiquotation url} options @{syntax name} |
@@{antiquotation cite} options @{syntax cartouche}? (@{syntax name} + @'and')
;
styles: '(' (style + ',') ')'
;
style: (@{syntax name} +)
;
@@{command print_antiquotations} ('!'?)
\<close>}
\<^descr> \<open>@{text s}\<close> prints uninterpreted source text \<open>s\<close>, i.e.\ inner syntax. This
is particularly useful to print portions of text according to the Isabelle
document style, without demanding well-formedness, e.g.\ small pieces of
terms that should not be parsed or type-checked yet.
It is also possible to write this in the short form \<open>\<open>s\<close>\<close> without any
further decoration.
\<^descr> \<open>@{theory_text s}\<close> prints uninterpreted theory source text \<open>s\<close>, i.e.\
outer syntax with command keywords and other tokens.
\<^descr> \<open>@{theory A}\<close> prints the name \<open>A\<close>, which is guaranteed to refer to a valid
ancestor theory in the current context.
\<^descr> \<open>@{thm a\<^sub>1 \<dots> a\<^sub>n}\<close> prints theorems \<open>a\<^sub>1 \<dots> a\<^sub>n\<close>. Full fact expressions are
allowed here, including attributes (\secref{sec:syn-att}).
\<^descr> \<open>@{prop \<phi>}\<close> prints a well-typed proposition \<open>\<phi>\<close>.
\<^descr> \<open>@{lemma \<phi> by m}\<close> proves a well-typed proposition \<open>\<phi>\<close> by method \<open>m\<close> and
prints the original \<open>\<phi>\<close>.
\<^descr> \<open>@{term t}\<close> prints a well-typed term \<open>t\<close>.
\<^descr> \<open>@{value t}\<close> evaluates a term \<open>t\<close> and prints its result, see also
@{command_ref (HOL) value}.
\<^descr> \<open>@{term_type t}\<close> prints a well-typed term \<open>t\<close> annotated with its type.
\<^descr> \<open>@{typeof t}\<close> prints the type of a well-typed term \<open>t\<close>.
\<^descr> \<open>@{const c}\<close> prints a logical or syntactic constant \<open>c\<close>.
\<^descr> \<open>@{abbrev c x\<^sub>1 \<dots> x\<^sub>n}\<close> prints a constant abbreviation \<open>c x\<^sub>1 \<dots> x\<^sub>n \<equiv> rhs\<close>
as defined in the current context.
\<^descr> \<open>@{typ \<tau>}\<close> prints a well-formed type \<open>\<tau>\<close>.
\<^descr> \<open>@{type \<kappa>}\<close> prints a (logical or syntactic) type constructor \<open>\<kappa>\<close>.
\<^descr> \<open>@{class c}\<close> prints a class \<open>c\<close>.
\<^descr> \<open>@{goals}\<close> prints the current \<^emph>\<open>dynamic\<close> goal state. This is mainly for
support of tactic-emulation scripts within Isar. Presentation of goal states
does not conform to the idea of human-readable proof documents!
When explaining proofs in detail it is usually better to spell out the
reasoning via proper Isar proof commands, instead of peeking at the internal
machine configuration.
\<^descr> \<open>@{subgoals}\<close> is similar to \<open>@{goals}\<close>, but does not print the main goal.
\<^descr> \<open>@{prf a\<^sub>1 \<dots> a\<^sub>n}\<close> prints the (compact) proof terms corresponding to the
theorems \<open>a\<^sub>1 \<dots> a\<^sub>n\<close>. Note that this requires proof terms to be switched on
for the current logic session.
\<^descr> \<open>@{full_prf a\<^sub>1 \<dots> a\<^sub>n}\<close> is like \<open>@{prf a\<^sub>1 \<dots> a\<^sub>n}\<close>, but prints the full
proof terms, i.e.\ also displays information omitted in the compact proof
term, which is denoted by ``\<open>_\<close>'' placeholders there.
\<^descr> \<open>@{ML s}\<close>, \<open>@{ML_op s}\<close>, \<open>@{ML_type s}\<close>, \<open>@{ML_structure s}\<close>, and
\<open>@{ML_functor s}\<close> check text \<open>s\<close> as ML value, infix operator, type,
structure, and functor respectively. The source is printed verbatim.
\<^descr> \<open>@{emph s}\<close> prints document source recursively, with {\LaTeX} markup
\<^verbatim>\<open>\emph{\<close>\<open>\<dots>\<close>\<^verbatim>\<open>}\<close>.
\<^descr> \<open>@{bold s}\<close> prints document source recursively, with {\LaTeX} markup
\<^verbatim>\<open>\textbf{\<close>\<open>\<dots>\<close>\<^verbatim>\<open>}\<close>.
\<^descr> \<open>@{verbatim s}\<close> prints uninterpreted source text literally as ASCII
characters, using some type-writer font style.
\<^descr> \<open>@{file path}\<close> checks that \<open>path\<close> refers to a file (or directory) and
prints it verbatim.
\<^descr> \<open>@{file_unchecked path}\<close> is like \<open>@{file path}\<close>, but does not check the
existence of the \<open>path\<close> within the file-system.
\<^descr> \<open>@{url name}\<close> produces markup for the given URL, which results in an
active hyperlink within the text.
\<^descr> \<open>@{cite name}\<close> produces a citation \<^verbatim>\<open>\cite{name}\<close> in {\LaTeX}, where the
name refers to some Bib{\TeX} database entry.
The variant \<open>@{cite \<open>opt\<close> name}\<close> produces \<^verbatim>\<open>\cite[opt]{name}\<close> with some
free-form optional argument. Multiple names are output with commas, e.g.
\<open>@{cite foo \<AND> bar}\<close> becomes \<^verbatim>\<open>\cite{foo,bar}\<close>.
The {\LaTeX} macro name is determined by the antiquotation option
@{antiquotation_option_def cite_macro}, or the configuration option
@{attribute cite_macro} in the context. For example, \<open>@{cite [cite_macro =
nocite] foobar}\<close> produces \<^verbatim>\<open>\nocite{foobar}\<close>.
\<^descr> @{command "print_antiquotations"} prints all document antiquotations that
are defined in the current context; the ``\<open>!\<close>'' option indicates extra
verbosity.
\<close>
subsection \<open>Styled antiquotations\<close>
text \<open>The antiquotations \<open>thm\<close>, \<open>prop\<close> and \<open>term\<close> admit an extra \<^emph>\<open>style\<close> specification to modify the
printed result. A style is specified by a name with a possibly
empty number of arguments; multiple styles can be sequenced with
commas. The following standard styles are available:
\<^descr> \<open>lhs\<close> extracts the first argument of any application
form with at least two arguments --- typically meta-level or
object-level equality, or any other binary relation.
\<^descr> \<open>rhs\<close> is like \<open>lhs\<close>, but extracts the second
argument.
\<^descr> \<open>concl\<close> extracts the conclusion \<open>C\<close> from a rule
in Horn-clause normal form \<open>A\<^sub>1 \<Longrightarrow> \<dots> A\<^sub>n \<Longrightarrow> C\<close>.
\<^descr> \<open>prem\<close> \<open>n\<close> extract premise number
\<open>n\<close> from from a rule in Horn-clause
normal form \<open>A\<^sub>1 \<Longrightarrow> \<dots> A\<^sub>n \<Longrightarrow> C\<close>
\<close>
subsection \<open>General options\<close>
text \<open>The following options are available to tune the printed output
of antiquotations. Note that many of these coincide with system and
configuration options of the same names.
\<^descr> @{antiquotation_option_def show_types}~\<open>= bool\<close> and
@{antiquotation_option_def show_sorts}~\<open>= bool\<close> control
printing of explicit type and sort constraints.
\<^descr> @{antiquotation_option_def show_structs}~\<open>= bool\<close>
controls printing of implicit structures.
\<^descr> @{antiquotation_option_def show_abbrevs}~\<open>= bool\<close>
controls folding of abbreviations.
\<^descr> @{antiquotation_option_def names_long}~\<open>= bool\<close> forces
names of types and constants etc.\ to be printed in their fully
qualified internal form.
\<^descr> @{antiquotation_option_def names_short}~\<open>= bool\<close>
forces names of types and constants etc.\ to be printed unqualified.
Note that internalizing the output again in the current context may
well yield a different result.
\<^descr> @{antiquotation_option_def names_unique}~\<open>= bool\<close>
determines whether the printed version of qualified names should be
made sufficiently long to avoid overlap with names declared further
back. Set to \<open>false\<close> for more concise output.
\<^descr> @{antiquotation_option_def eta_contract}~\<open>= bool\<close>
prints terms in \<open>\<eta>\<close>-contracted form.
\<^descr> @{antiquotation_option_def display}~\<open>= bool\<close> indicates
if the text is to be output as multi-line ``display material'',
rather than a small piece of text without line breaks (which is the
default).
In this mode the embedded entities are printed in the same style as
the main theory text.
\<^descr> @{antiquotation_option_def break}~\<open>= bool\<close> controls
line breaks in non-display material.
\<^descr> @{antiquotation_option_def quotes}~\<open>= bool\<close> indicates
if the output should be enclosed in double quotes.
\<^descr> @{antiquotation_option_def mode}~\<open>= name\<close> adds \<open>name\<close> to the print mode to be used for presentation. Note that the
standard setup for {\LaTeX} output is already present by default,
including the modes \<open>latex\<close> and \<open>xsymbols\<close>.
\<^descr> @{antiquotation_option_def margin}~\<open>= nat\<close> and
@{antiquotation_option_def indent}~\<open>= nat\<close> change the margin
or indentation for pretty printing of display material.
\<^descr> @{antiquotation_option_def goals_limit}~\<open>= nat\<close>
determines the maximum number of subgoals to be printed (for goal-based
antiquotation).
\<^descr> @{antiquotation_option_def source}~\<open>= bool\<close> prints the
original source text of the antiquotation arguments, rather than its
internal representation. Note that formal checking of
@{antiquotation "thm"}, @{antiquotation "term"}, etc. is still
enabled; use the @{antiquotation "text"} antiquotation for unchecked
output.
Regular \<open>term\<close> and \<open>typ\<close> antiquotations with \<open>source = false\<close> involve a full round-trip from the original source
to an internalized logical entity back to a source form, according
to the syntax of the current context. Thus the printed output is
not under direct control of the author, it may even fluctuate a bit
as the underlying theory is changed later on.
In contrast, @{antiquotation_option source}~\<open>= true\<close>
admits direct printing of the given source text, with the desirable
well-formedness check in the background, but without modification of
the printed text.
For Boolean flags, ``\<open>name = true\<close>'' may be abbreviated as
``\<open>name\<close>''. All of the above flags are disabled by default,
unless changed specifically for a logic session in the corresponding
\<^verbatim>\<open>ROOT\<close> file.
\<close>
section \<open>Markup via command tags \label{sec:tags}\<close>
text \<open>Each Isabelle/Isar command may be decorated by additional
presentation tags, to indicate some modification in the way it is
printed in the document.
@{rail \<open>
@{syntax_def tags}: ( tag * )
;
tag: '%' (@{syntax ident} | @{syntax string})
\<close>}
Some tags are pre-declared for certain classes of commands, serving
as default markup if no tags are given in the text:
\<^medskip>
\begin{tabular}{ll}
\<open>theory\<close> & theory begin/end \\
\<open>proof\<close> & all proof commands \\
\<open>ML\<close> & all commands involving ML code \\
\end{tabular}
\<^medskip>
The Isabelle document preparation system
@{cite "isabelle-system"} allows tagged command regions to be presented
specifically, e.g.\ to fold proof texts, or drop parts of the text
completely.
For example ``@{command "by"}~\<open>%invisible auto\<close>'' causes
that piece of proof to be treated as \<open>invisible\<close> instead of
\<open>proof\<close> (the default), which may be shown or hidden
depending on the document setup. In contrast, ``@{command
"by"}~\<open>%visible auto\<close>'' forces this text to be shown
invariably.
Explicit tag specifications within a proof apply to all subsequent
commands of the same level of nesting. For example, ``@{command
"proof"}~\<open>%visible \<dots>\<close>~@{command "qed"}'' forces the whole
sub-proof to be typeset as \<open>visible\<close> (unless some of its parts
are tagged differently).
\<^medskip>
Command tags merely produce certain markup environments for
type-setting. The meaning of these is determined by {\LaTeX}
macros, as defined in @{file "~~/lib/texinputs/isabelle.sty"} or
by the document author. The Isabelle document preparation tools
also provide some high-level options to specify the meaning of
arbitrary tags to ``keep'', ``drop'', or ``fold'' the corresponding
parts of the text. Logic sessions may also specify ``document
versions'', where given tags are interpreted in some particular way.
Again see @{cite "isabelle-system"} for further details.
\<close>
section \<open>Railroad diagrams\<close>
text \<open>
\begin{matharray}{rcl}
@{antiquotation_def "rail"} & : & \<open>antiquotation\<close> \\
\end{matharray}
@{rail \<open>
'rail' @{syntax text}
\<close>}
The @{antiquotation rail} antiquotation allows to include syntax
diagrams into Isabelle documents. {\LaTeX} requires the style file
@{file "~~/lib/texinputs/railsetup.sty"}, which can be used via
\<^verbatim>\<open>\usepackage{railsetup}\<close> in \<^verbatim>\<open>root.tex\<close>, for example.
The rail specification language is quoted here as Isabelle @{syntax
string} or text @{syntax "cartouche"}; it has its own grammar given
below.
\begingroup
\def\isasymnewline{\isatt{\isacharbackslash\isacharless newline\isachargreater}}
@{rail \<open>
rule? + ';'
;
rule: ((identifier | @{syntax antiquotation}) ':')? body
;
body: concatenation + '|'
;
concatenation: ((atom '?'?) +) (('*' | '+') atom?)?
;
atom: '(' body? ')' | identifier |
'@'? (string | @{syntax antiquotation}) |
'\<newline>'
\<close>}
\endgroup
The lexical syntax of \<open>identifier\<close> coincides with that of
@{syntax ident} in regular Isabelle syntax, but \<open>string\<close> uses
single quotes instead of double quotes of the standard @{syntax
string} category.
Each \<open>rule\<close> defines a formal language (with optional name),
using a notation that is similar to EBNF or regular expressions with
recursion. The meaning and visual appearance of these rail language
elements is illustrated by the following representative examples.
\<^item> Empty \<^verbatim>\<open>()\<close>
@{rail \<open>()\<close>}
\<^item> Nonterminal \<^verbatim>\<open>A\<close>
@{rail \<open>A\<close>}
\<^item> Nonterminal via Isabelle antiquotation \<^verbatim>\<open>@{syntax method}\<close>
@{rail \<open>@{syntax method}\<close>}
\<^item> Terminal \<^verbatim>\<open>'xyz'\<close>
@{rail \<open>'xyz'\<close>}
\<^item> Terminal in keyword style \<^verbatim>\<open>@'xyz'\<close>
@{rail \<open>@'xyz'\<close>}
\<^item> Terminal via Isabelle antiquotation \<^verbatim>\<open>@@{method rule}\<close>
@{rail \<open>@@{method rule}\<close>}
\<^item> Concatenation \<^verbatim>\<open>A B C\<close>
@{rail \<open>A B C\<close>}
\<^item> Newline inside concatenation \<^verbatim>\<open>A B C \<newline> D E F\<close>
@{rail \<open>A B C \<newline> D E F\<close>}
\<^item> Variants \<^verbatim>\<open>A | B | C\<close>
@{rail \<open>A | B | C\<close>}
\<^item> Option \<^verbatim>\<open>A ?\<close>
@{rail \<open>A ?\<close>}
\<^item> Repetition \<^verbatim>\<open>A *\<close>
@{rail \<open>A *\<close>}
\<^item> Repetition with separator \<^verbatim>\<open>A * sep\<close>
@{rail \<open>A * sep\<close>}
\<^item> Strict repetition \<^verbatim>\<open>A +\<close>
@{rail \<open>A +\<close>}
\<^item> Strict repetition with separator \<^verbatim>\<open>A + sep\<close>
@{rail \<open>A + sep\<close>}
\<close>
section \<open>Draft presentation\<close>
text \<open>
\begin{matharray}{rcl}
@{command_def "display_drafts"}\<open>\<^sup>*\<close> & : & \<open>any \<rightarrow>\<close> \\
\end{matharray}
@{rail \<open>
@@{command display_drafts} (@{syntax name} +)
\<close>}
\<^descr> @{command "display_drafts"}~\<open>paths\<close> performs simple output of a
given list of raw source files. Only those symbols that do not require
additional {\LaTeX} packages are displayed properly, everything else is left
verbatim.
\<close>
end