theory Document_Preparation
imports Main Base
begin
chapter ‹Document preparation \label{ch:document-prep}›
text ‹
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 ∗‹session› in batch mode, as
explained in the ∗‹The Isabelle System Manual› @{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.
›
section ‹Markup commands \label{sec:markup}›
text ‹
\begin{matharray}{rcl}
@{command_def "chapter"} & : & ‹any → any› \\
@{command_def "section"} & : & ‹any → any› \\
@{command_def "subsection"} & : & ‹any → any› \\
@{command_def "subsubsection"} & : & ‹any → any› \\
@{command_def "paragraph"} & : & ‹any → any› \\
@{command_def "subparagraph"} & : & ‹any → any› \\
@{command_def "text"} & : & ‹any → any› \\
@{command_def "txt"} & : & ‹any → any› \\
@{command_def "text_raw"} & : & ‹any → any› \\
\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 🗏‹~~/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>‹
(@@{command chapter} | @@{command section} | @@{command subsection} |
@@{command subsubsection} | @@{command paragraph} | @@{command subparagraph})
@{syntax text} ';'? |
(@@{command text} | @@{command txt} | @@{command text_raw}) @{syntax text}
›
➧ @{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 ▩‹\isamarkupchapter›, ▩‹\isamarkupsection›,
▩‹\isamarkupsubsection› etc.\
➧ @{command text} and @{command txt} specify paragraphs of plain text.
This corresponds to a {\LaTeX} environment ▩‹\begin{isamarkuptext}› ‹…›
▩‹\end{isamarkuptext}› etc.
➧ @{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 ∗‹document antiquotations›, see also \secref{sec:antiq}. These
are interpreted in the present theory or proof context.
┉
The proof markup commands closely resemble those for theory specifications,
but have a different formal status and produce different {\LaTeX} macros.
›
section ‹Document antiquotations \label{sec:antiq}›
text ‹
\begin{matharray}{rcl}
@{antiquotation_def "theory"} & : & ‹antiquotation› \\
@{antiquotation_def "thm"} & : & ‹antiquotation› \\
@{antiquotation_def "lemma"} & : & ‹antiquotation› \\
@{antiquotation_def "prop"} & : & ‹antiquotation› \\
@{antiquotation_def "term"} & : & ‹antiquotation› \\
@{antiquotation_def term_type} & : & ‹antiquotation› \\
@{antiquotation_def typeof} & : & ‹antiquotation› \\
@{antiquotation_def const} & : & ‹antiquotation› \\
@{antiquotation_def abbrev} & : & ‹antiquotation› \\
@{antiquotation_def typ} & : & ‹antiquotation› \\
@{antiquotation_def type} & : & ‹antiquotation› \\
@{antiquotation_def class} & : & ‹antiquotation› \\
@{antiquotation_def locale} & : & ‹antiquotation› \\
@{antiquotation_def "text"} & : & ‹antiquotation› \\
@{antiquotation_def goals} & : & ‹antiquotation› \\
@{antiquotation_def subgoals} & : & ‹antiquotation› \\
@{antiquotation_def prf} & : & ‹antiquotation› \\
@{antiquotation_def full_prf} & : & ‹antiquotation› \\
@{antiquotation_def ML} & : & ‹antiquotation› \\
@{antiquotation_def ML_op} & : & ‹antiquotation› \\
@{antiquotation_def ML_type} & : & ‹antiquotation› \\
@{antiquotation_def ML_structure} & : & ‹antiquotation› \\
@{antiquotation_def ML_functor} & : & ‹antiquotation› \\
@{antiquotation_def emph} & : & ‹antiquotation› \\
@{antiquotation_def bold} & : & ‹antiquotation› \\
@{antiquotation_def verbatim} & : & ‹antiquotation› \\
@{antiquotation_def session} & : & ‹antiquotation› \\
@{antiquotation_def "file"} & : & ‹antiquotation› \\
@{antiquotation_def "url"} & : & ‹antiquotation› \\
@{antiquotation_def "cite"} & : & ‹antiquotation› \\
@{command_def "print_antiquotations"}‹⇧*› & : & ‹context →› \\
\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 ∗‹document antiquotations›.
For example, embedding ▩‹@{term [show_types] "f x = a + x"}›
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.
┉
Antiquotations are in general written as
▩‹@{›‹name›~▩‹[›‹options›▩‹]›~‹arguments›▩‹}›. The short form
▩‹\›▩‹<^›‹name›▩‹>›‹‹argument_content›› (without surrounding ▩‹@{›‹…›▩‹}›)
works for a single argument that is a cartouche. A cartouche without special
decoration is equivalent to ▩‹\<^cartouche>›‹‹argument_content››, which is
equivalent to ▩‹@{cartouche›~‹‹argument_content››▩‹}›. 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, ‹‹foo_bar + baz ≤ bazar›› prints literal quasi-formal text
(unchecked). A control symbol ▩‹\›▩‹<^›‹name›▩‹>› within the body text, but
without a subsequent cartouche, is equivalent to ▩‹@{›‹name›▩‹}›.
\begingroup
\def\isasymcontrolstart{\isatt{\isacharbackslash\isacharless\isacharcircum}}
\<^rail>‹
@{syntax_def antiquotation}:
'@{' antiquotation_body '}' |
'\<controlstart>' @{syntax_ref name} '>' @{syntax_ref cartouche} |
@{syntax_ref cartouche}
;
options: '[' (option * ',') ']'
;
option: @{syntax name} | @{syntax name} '=' @{syntax name}
;
›
\endgroup
Note that the syntax of antiquotations may ∗‹not› include source comments
▩‹(*›~‹…›~▩‹*)› nor verbatim text ▩‹{*›~‹…›~▩‹*}›.
%% FIXME less monolithic presentation, move to individual sections!?
\<^rail>‹
@{syntax_def antiquotation_body}:
(@@{antiquotation text} | @@{antiquotation cartouche} | @@{antiquotation theory_text})
options @{syntax text} |
@@{antiquotation theory} options @{syntax embedded} |
@@{antiquotation thm} options styles @{syntax thms} |
@@{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 embedded} |
@@{antiquotation class} options @{syntax embedded} |
@@{antiquotation locale} options @{syntax embedded} |
(@@{antiquotation command} | @@{antiquotation method} | @@{antiquotation attribute})
options @{syntax name}
;
@{syntax antiquotation}:
@@{antiquotation goals} options |
@@{antiquotation subgoals} options |
@@{antiquotation prf} options @{syntax thms} |
@@{antiquotation full_prf} options @{syntax thms} |
@@{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 session} options @{syntax embedded} |
@@{antiquotation path} options @{syntax embedded} |
@@{antiquotation "file"} options @{syntax name} |
@@{antiquotation dir} options @{syntax name} |
@@{antiquotation url} options @{syntax embedded} |
@@{antiquotation cite} options @{syntax cartouche}? (@{syntax name} + @'and')
;
styles: '(' (style + ',') ')'
;
style: (@{syntax name} +)
;
@@{command print_antiquotations} ('!'?)
›
➧ ‹@{text s}› prints uninterpreted source text ‹s›, 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 ‹‹s›› without any
further decoration.
➧ ‹@{theory_text s}› prints uninterpreted theory source text ‹s›, i.e.\
outer syntax with command keywords and other tokens.
➧ ‹@{theory A}› prints the session-qualified theory name ‹A›, which is
guaranteed to refer to a valid ancestor theory in the current context.
➧ ‹@{thm a⇩1 … a⇩n}› prints theorems ‹a⇩1 … a⇩n›. Full fact expressions are
allowed here, including attributes (\secref{sec:syn-att}).
➧ ‹@{prop φ}› prints a well-typed proposition ‹φ›.
➧ ‹@{lemma φ by m}› proves a well-typed proposition ‹φ› by method ‹m› and
prints the original ‹φ›.
➧ ‹@{term t}› prints a well-typed term ‹t›.
➧ ‹@{value t}› evaluates a term ‹t› and prints its result, see also
@{command_ref (HOL) value}.
➧ ‹@{term_type t}› prints a well-typed term ‹t› annotated with its type.
➧ ‹@{typeof t}› prints the type of a well-typed term ‹t›.
➧ ‹@{const c}› prints a logical or syntactic constant ‹c›.
➧ ‹@{abbrev c x⇩1 … x⇩n}› prints a constant abbreviation ‹c x⇩1 … x⇩n ≡ rhs›
as defined in the current context.
➧ ‹@{typ τ}› prints a well-formed type ‹τ›.
➧ ‹@{type κ}› prints a (logical or syntactic) type constructor ‹κ›.
➧ ‹@{class c}› prints a class ‹c›.
➧ ‹@{locale c}› prints a locale ‹c›.
➧ ‹@{command name}›, ‹@{method name}›, ‹@{attribute name}› print checked
entities of the Isar language.
➧ ‹@{goals}› prints the current ∗‹dynamic› 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.
➧ ‹@{subgoals}› is similar to ‹@{goals}›, but does not print the main goal.
➧ ‹@{prf a⇩1 … a⇩n}› prints the (compact) proof terms corresponding to the
theorems ‹a⇩1 … a⇩n›. Note that this requires proof terms to be switched on
for the current logic session.
➧ ‹@{full_prf a⇩1 … a⇩n}› is like ‹@{prf a⇩1 … a⇩n}›, but prints the full
proof terms, i.e.\ also displays information omitted in the compact proof
term, which is denoted by ``‹_›'' placeholders there.
➧ ‹@{ML s}›, ‹@{ML_op s}›, ‹@{ML_type s}›, ‹@{ML_structure s}›, and
‹@{ML_functor s}› check text ‹s› as ML value, infix operator, type,
structure, and functor respectively. The source is printed verbatim.
➧ ‹@{emph s}› prints document source recursively, with {\LaTeX} markup
▩‹\emph{›‹…›▩‹}›.
➧ ‹@{bold s}› prints document source recursively, with {\LaTeX} markup
▩‹\textbf{›‹…›▩‹}›.
➧ ‹@{verbatim s}› prints uninterpreted source text literally as ASCII
characters, using some type-writer font style.
➧ ‹@{session name}› prints given session name verbatim. The name is checked
wrt.\ the dependencies of the current session.
➧ ‹@{path name}› prints the file-system path name verbatim.
➧ ‹@{file name}› is like ‹@{path name}›, but ensures that ‹name› refers to a
plain file.
➧ ‹@{dir name}› is like ‹@{path name}›, but ensures that ‹name› refers to a
directory.
➧ ‹@{url name}› produces markup for the given URL, which results in an
active hyperlink within the text.
➧ ‹@{cite name}› produces a citation ▩‹\cite{name}› in {\LaTeX}, where the
name refers to some Bib{\TeX} database entry. This is only checked in
batch-mode session builds.
The variant ‹@{cite ‹opt› name}› produces ▩‹\cite[opt]{name}› with some
free-form optional argument. Multiple names are output with commas, e.g.
‹@{cite foo \<AND> bar}› becomes ▩‹\cite{foo,bar}›.
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, ‹@{cite [cite_macro =
nocite] foobar}› produces ▩‹\nocite{foobar}›.
➧ @{command "print_antiquotations"} prints all document antiquotations that
are defined in the current context; the ``‹!›'' option indicates extra
verbosity.
›
subsection ‹Styled antiquotations›
text ‹
The antiquotations ‹thm›, ‹prop› and ‹term› admit an extra ∗‹style›
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:
➧ ‹lhs› 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.
➧ ‹rhs› is like ‹lhs›, but extracts the second argument.
➧ ‹concl› extracts the conclusion ‹C› from a rule in Horn-clause normal form
‹A⇩1 ⟹ … A⇩n ⟹ C›.
➧ ‹prem› ‹n› extract premise number ‹n› from from a rule in Horn-clause
normal form ‹A⇩1 ⟹ … A⇩n ⟹ C›.
›
subsection ‹General options›
text ‹
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.
➧ @{antiquotation_option_def show_types}~‹= bool› and
@{antiquotation_option_def show_sorts}~‹= bool› control printing of
explicit type and sort constraints.
➧ @{antiquotation_option_def show_structs}~‹= bool› controls printing of
implicit structures.
➧ @{antiquotation_option_def show_abbrevs}~‹= bool› controls folding of
abbreviations.
➧ @{antiquotation_option_def names_long}~‹= bool› forces names of types
and constants etc.\ to be printed in their fully qualified internal form.
➧ @{antiquotation_option_def names_short}~‹= bool› 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.
➧ @{antiquotation_option_def names_unique}~‹= bool› determines whether the
printed version of qualified names should be made sufficiently long to
avoid overlap with names declared further back. Set to ‹false› for more
concise output.
➧ @{antiquotation_option_def eta_contract}~‹= bool› prints terms in
‹η›-contracted form.
➧ @{antiquotation_option_def display}~‹= bool› 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.
➧ @{antiquotation_option_def break}~‹= bool› controls line breaks in
non-display material.
➧ @{antiquotation_option_def cartouche}~‹= bool› indicates if the output
should be delimited as cartouche.
➧ @{antiquotation_option_def quotes}~‹= bool› indicates if the output
should be delimited via double quotes (option @{antiquotation_option
cartouche} takes precedence). Note that the Isabelle {\LaTeX} styles may
suppress quotes on their own account.
➧ @{antiquotation_option_def mode}~‹= name› adds ‹name› to the print mode
to be used for presentation. Note that the standard setup for {\LaTeX}
output is already present by default, with mode ``‹latex›''.
➧ @{antiquotation_option_def margin}~‹= nat› and
@{antiquotation_option_def indent}~‹= nat› change the margin or
indentation for pretty printing of display material.
➧ @{antiquotation_option_def goals_limit}~‹= nat› determines the maximum
number of subgoals to be printed (for goal-based antiquotation).
➧ @{antiquotation_option_def source}~‹= bool› 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 ‹term› and ‹typ› antiquotations with ‹source = false› 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}~‹= true› admits direct
printing of the given source text, with the desirable well-formedness
check in the background, but without modification of the printed text.
Cartouche delimiters of the argument are stripped for antiquotations that
are internally categorized as ``embedded''.
➧ @{antiquotation_option_def source_cartouche} is like
@{antiquotation_option source}, but cartouche delimiters are always
preserved in the output.
For Boolean flags, ``‹name = true›'' may be abbreviated as ``‹name›''. All
of the above flags are disabled by default, unless changed specifically for
a logic session in the corresponding ▩‹ROOT› file.
›
section ‹Markdown-like text structure›
text ‹
The markup commands @{command_ref text}, @{command_ref txt}, @{command_ref
text_raw} (\secref{sec:markup}) consist of plain text. Its internal
structure consists of paragraphs and (nested) lists, using special Isabelle
symbols and some rules for indentation and blank lines. This quasi-visual
format resembles ∗‹Markdown›⁋‹🌐‹http://commonmark.org››, but the full
complexity of that notation is avoided.
This is a summary of the main principles of minimal Markdown in Isabelle:
▪ List items start with the following markers
➧[itemize:] ▩‹▪›
➧[enumerate:] ▩‹▸›
➧[description:] ▩‹➧›
▪ Adjacent list items with same indentation and same marker are grouped
into a single list.
▪ Singleton blank lines separate paragraphs.
▪ Multiple blank lines escape from the current list hierarchy.
Notable differences to official Markdown:
▪ Indentation of list items needs to match exactly.
▪ Indentation is unlimited (official Markdown interprets four spaces as
block quote).
▪ List items always consist of paragraphs --- there is no notion of
``tight'' list.
▪ Section headings are expressed via Isar document markup commands
(\secref{sec:markup}).
▪ URLs, font styles, other special content is expressed via antiquotations
(\secref{sec:antiq}), usually with proper nesting of sub-languages via
text cartouches.
›
section ‹Document markers and command tags \label{sec:document-markers}›
text ‹
\emph{Document markers} are formal comments of the form ‹✐‹marker_body››
(using the control symbol ▩‹✐›) and may occur anywhere within the
outer syntax of a command: the inner syntax of a marker body resembles that
for attributes (\secref{sec:syn-att}). In contrast, \emph{Command tags} may
only occur after a command keyword and are treated as special markers as
explained below.
\<^rail>‹
@{syntax_def marker}: '✐' @{syntax cartouche}
;
@{syntax_def marker_body}: (@{syntax name} @{syntax args} * ',')
;
@{syntax_def tags}: tag*
;
tag: '%' (@{syntax short_ident} | @{syntax string})
›
Document markers are stripped from the document output, but surrounding
white-space is preserved: e.g.\ a marker at the end of a line does not
affect the subsequent line break. Markers operate within the semantic
presentation context of a command, and may modify it to change the overall
appearance of a command span (e.g.\ by adding tags).
Each document marker has its own syntax defined in the theory context; the
following markers are predefined in Isabelle/Pure:
\<^rail>‹
(@@{document_marker_def title} |
@@{document_marker_def creator} |
@@{document_marker_def contributor} |
@@{document_marker_def date} |
@@{document_marker_def license} |
@@{document_marker_def description}) @{syntax embedded}
;
@@{document_marker_def tag} (scope?) @{syntax name}
;
scope: '(' ('proof' | 'command') ')'
›
➧ ‹✐‹title arg››, ‹✐‹creator arg››, ‹✐‹contributor arg››, ‹✐‹date arg››,
‹✐‹license arg››, and ‹✐‹description arg›› produce markup in the PIDE
document, without any immediate effect on typesetting. This vocabulary is
taken from the Dublin Core Metadata
Initiative⁋‹🌐‹https://www.dublincore.org/specifications/dublin-core/dcmi-terms››.
The argument is an uninterpreted string, except for @{document_marker
description}, which consists of words that are subject to spell-checking.
➧ ‹✐‹tag name›› updates the list of command tags in the presentation
context: later declarations take precedence, so ‹✐‹tag a, tag b, tag c››
produces a reversed list. The default tags are given by the original
⬚‹keywords› declaration of a command, and the system option
@{system_option_ref document_tags}.
The optional ‹scope› tells how far the tagging is applied to subsequent
proof structure: ``⬚‹("proof")›'' means it applies to the following proof
text, and ``⬚‹(command)›'' means it only applies to the current command.
The default within a proof body is ``⬚‹("proof")›'', but for toplevel goal
statements it is ``⬚‹(command)›''. Thus a ‹tag› marker for ⬚‹theorem›,
⬚‹lemma› etc. does \emph{not} affect its proof by default.
An old-style command tag ▩‹%›‹name› is treated like a document marker
‹✐‹tag (proof) name››: the list of command tags precedes the list of
document markers. The head of the resulting tags in the presentation
context is turned into {\LaTeX} environments to modify the type-setting.
The following tags are pre-declared for certain classes of commands, and
serve as default markup for certain kinds of commands:
┉
\begin{tabular}{ll}
‹document› & document markup commands \\
‹theory› & theory begin/end \\
‹proof› & all proof commands \\
‹ML› & all commands involving ML code \\
\end{tabular}
┉
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 ``⬚‹by auto›~‹✐‹tag invisible››'' causes that piece of proof to
be treated as ‹invisible› instead of ‹proof› (the default), which may be
shown or hidden depending on the document setup. In contrast, ``⬚‹by
auto›~‹✐‹tag visible››'' 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, ``⬚‹proof›~‹✐‹tag invisible›
…›~⬚‹qed›'' forces the whole sub-proof to be typeset as ‹visible› (unless
some of its parts are tagged differently).
┉
Command tags merely produce certain markup environments for type-setting.
The meaning of these is determined by {\LaTeX} macros, as defined in
🗏‹~~/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.
›
section ‹Railroad diagrams›
text ‹
\begin{matharray}{rcl}
@{antiquotation_def "rail"} & : & ‹antiquotation› \\
\end{matharray}
\<^rail>‹
'rail' @{syntax text}
›
The @{antiquotation rail} antiquotation allows to include syntax diagrams
into Isabelle documents. {\LaTeX} requires the style file
🗏‹~~/lib/texinputs/railsetup.sty›, which can be used via
▩‹\usepackage{railsetup}› in ▩‹root.tex›, 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>‹
rule? + ';'
;
rule: ((identifier | @{syntax antiquotation}) ':')? body
;
body: concatenation + '|'
;
concatenation: ((atom '?'?) +) (('*' | '+') atom?)?
;
atom: '(' body? ')' | identifier |
'@'? (string | @{syntax antiquotation}) |
'⏎'
›
\endgroup
The lexical syntax of ‹identifier› coincides with that of @{syntax
short_ident} in regular Isabelle syntax, but ‹string› uses single quotes
instead of double quotes of the standard @{syntax string} category.
Each ‹rule› 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.
▪ Empty ▩‹()›
\<^rail>‹()›
▪ Nonterminal ▩‹A›
\<^rail>‹A›
▪ Nonterminal via Isabelle antiquotation ▩‹@{syntax method}›
\<^rail>‹@{syntax method}›
▪ Terminal ▩‹'xyz'›
\<^rail>‹'xyz'›
▪ Terminal in keyword style ▩‹@'xyz'›
\<^rail>‹@'xyz'›
▪ Terminal via Isabelle antiquotation ▩‹@@{method rule}›
\<^rail>‹@@{method rule}›
▪ Concatenation ▩‹A B C›
\<^rail>‹A B C›
▪ Newline inside concatenation ▩‹A B C ⏎ D E F›
\<^rail>‹A B C ⏎ D E F›
▪ Variants ▩‹A | B | C›
\<^rail>‹A | B | C›
▪ Option ▩‹A ?›
\<^rail>‹A ?›
▪ Repetition ▩‹A *›
\<^rail>‹A *›
▪ Repetition with separator ▩‹A * sep›
\<^rail>‹A * sep›
▪ Strict repetition ▩‹A +›
\<^rail>‹A +›
▪ Strict repetition with separator ▩‹A + sep›
\<^rail>‹A + sep›
›
end