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(*<*)
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theory Documents = Main:
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(*>*)
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section {* Concrete Syntax \label{sec:concrete-syntax} *}
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text {*
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The core concept of Isabelle's elaborate infrastructure for concrete
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syntax is that of general \bfindex{mixfix annotations}. Associated
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with any kind of constant declaration, mixfixes affect both the
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grammar productions for the parser and output templates for the
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pretty printer.
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In full generality, parser and pretty printer configuration is a
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rather subtle affair, see \cite{isabelle-ref} for details. Syntax
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specifications given by end-users need to interact properly with the
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existing setup of Isabelle/Pure and Isabelle/HOL. It is
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particularly important to get the precedence of new syntactic
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constructs right, avoiding ambiguities with existing elements.
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\medskip Subsequently we introduce a few simple syntax declaration
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forms that already cover many common situations fairly well.
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*}
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subsection {* Infix Annotations *}
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text {*
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Syntax annotations may be included wherever constants are declared
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directly or indirectly, including \isacommand{consts},
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\isacommand{constdefs}, or \isacommand{datatype} (for the
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constructor operations). Type-constructors may be annotated as
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well, although this is less frequently encountered in practice (the
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infix type @{text "\<times>"} comes to mind).
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Infix declarations\index{infix annotations} provide a useful special
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case of mixfixes, where users need not care about the full details
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of priorities, nesting, spacing, etc. The following example of the
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exclusive-or operation on boolean values illustrates typical infix
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declarations arising in practice.
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*}
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constdefs
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xor :: "bool \<Rightarrow> bool \<Rightarrow> bool" (infixl "[+]" 60)
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"A [+] B \<equiv> (A \<and> \<not> B) \<or> (\<not> A \<and> B)"
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text {*
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\noindent Now @{text "xor A B"} and @{text "A [+] B"} refer to the
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same expression internally. Any curried function with at least two
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arguments may be associated with infix syntax. For partial
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applications with less than two operands there is a special notation
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with \isa{op} prefix: @{text xor} without arguments is represented
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as @{text "op [+]"}; together with plain prefix application this
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turns @{text "xor A"} into @{text "op [+] A"}.
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\medskip The keyword \isakeyword{infixl} seen above specifies an
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infix operator that is nested to the \emph{left}: in iterated
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applications the more complex expression appears on the left-hand
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side, @{term "A [+] B [+] C"} stands for @{text "(A [+] B) [+] C"}.
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Similarly, \isakeyword{infixr} specifies nesting to the
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\emph{right}, reading @{term "A [+] B [+] C"} as @{text "A [+] (B
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[+] C)"}. In contrast, a \emph{non-oriented} declaration via
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\isakeyword{infix} would render @{term "A [+] B [+] C"} illegal, but
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demand explicit parentheses to indicate the intended grouping.
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The string @{text [source] "[+]"} in our annotation refers to the
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concrete syntax to represent the operator (a literal token), while
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the number @{text 60} determines the precedence of the construct
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(i.e.\ the syntactic priorities of the arguments and result). As it
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happens, Isabelle/HOL already uses up many popular combinations of
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ASCII symbols for its own use, including both @{text "+"} and @{text
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"++"}. As a rule of thumb, more awkward character combinations are
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more likely to be still available for user extensions, just as our
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present @{text "[+]"}.
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Operator precedence also needs some special considerations. The
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admissible range is 0--1000. Very low or high priorities are
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basically reserved for the meta-logic. Syntax of Isabelle/HOL
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mainly uses the range of 10--100: the equality infix @{text "="} is
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centered at 50, logical connectives (like @{text "\<or>"} and @{text
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"\<and>"}) are below 50, and algebraic ones (like @{text "+"} and @{text
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"*"}) above 50. User syntax should strive to coexist with common
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HOL forms, or use the mostly unused range 100--900.
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*}
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subsection {* Mathematical Symbols \label{sec:syntax-symbols} *}
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text {*
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Concrete syntax based on plain ASCII characters has its inherent
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limitations. Rich mathematical notation demands a larger repertoire
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of glyphs. Several standards of extended character sets have been
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proposed over decades, but none has become universally available so
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far. Isabelle supports a generic notion of \bfindex{symbols} as the
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smallest entities of source text, without referring to internal
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encodings. There are three kinds of such ``generalized
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characters'':
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\begin{enumerate}
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\item 7-bit ASCII characters
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\item named symbols: \verb,\,\verb,<,$ident$\verb,>,
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\item named control symbols: \verb,\,\verb,<^,$ident$\verb,>,
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\end{enumerate}
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Here $ident$ may be any identifier according to the usual Isabelle
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conventions. This results in an infinite store of symbols, whose
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interpretation is left to further front-end tools. For example,
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both the user-interface of Proof~General + X-Symbol and the Isabelle
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document processor (see \S\ref{sec:document-preparation}) display
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the \verb,\,\verb,<forall>, symbol as @{text \<forall>}.
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A list of standard Isabelle symbols is given in
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\cite[appendix~A]{isabelle-sys}. Users may introduce their own
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interpretation of further symbols by configuring the appropriate
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front-end tool accordingly, e.g.\ by defining certain {\LaTeX}
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macros (see also \S\ref{sec:doc-prep-symbols}). There are also a
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few predefined control symbols, such as \verb,\,\verb,<^sub>, and
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\verb,\,\verb,<^sup>, for sub- and superscript of the subsequent
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(printable) symbol, respectively. For example, \verb,A\<^sup>\<star>, is
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output as @{text "A\<^sup>\<star>"}.
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\medskip The following version of our @{text xor} definition uses a
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standard Isabelle symbol to achieve typographically more pleasing
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output than before.
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*}
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(*<*)
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hide const xor
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ML_setup {* Context.>> (Theory.add_path "version1") *}
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(*>*)
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constdefs
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xor :: "bool \<Rightarrow> bool \<Rightarrow> bool" (infixl "\<oplus>" 60)
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"A \<oplus> B \<equiv> (A \<and> \<not> B) \<or> (\<not> A \<and> B)"
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(*<*)
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local
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(*>*)
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text {*
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\noindent The X-Symbol package within Proof~General provides several
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input methods to enter @{text \<oplus>} in the text. If all fails one may
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just type a named entity \verb,\,\verb,<oplus>, by hand; the display
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will be adapted immediately after continuing input.
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\medskip A slightly more refined scheme of providing alternative
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syntax forms uses the \bfindex{print mode} concept of Isabelle (see
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also \cite{isabelle-ref}). By convention, the mode of
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``$xsymbols$'' is enabled whenever Proof~General's X-Symbol mode or
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{\LaTeX} output is active. Now consider the following hybrid
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declaration of @{text xor}:
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*}
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(*<*)
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hide const xor
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ML_setup {* Context.>> (Theory.add_path "version2") *}
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(*>*)
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constdefs
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xor :: "bool \<Rightarrow> bool \<Rightarrow> bool" (infixl "[+]\<ignore>" 60)
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"A [+]\<ignore> B \<equiv> (A \<and> \<not> B) \<or> (\<not> A \<and> B)"
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syntax (xsymbols)
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xor :: "bool \<Rightarrow> bool \<Rightarrow> bool" (infixl "\<oplus>\<ignore>" 60)
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(*<*)
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local
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(*>*)
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text {*
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The \commdx{syntax} command introduced here acts like
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\isakeyword{consts}, but without declaring a logical constant. The
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print mode specification of \isakeyword{syntax}, here @{text
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"(xsymbols)"}, is optional. Also note that its type merely serves
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for syntactic purposes, and is \emph{not} checked for consistency
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with the real constant.
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\medskip We may now write @{text "A [+] B"} or @{text "A \<oplus> B"} in
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input, while output uses the nicer syntax of $xsymbols$, provided
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that print mode is active. Such an arrangement is particularly
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useful for interactive development, where users may type plain ASCII
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text, but gain improved visual feedback from the system.
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*}
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subsection {* Prefix Annotations *}
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text {*
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Prefix syntax annotations\index{prefix annotation} are another
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degenerate form of mixfixes \cite{isabelle-ref}, without any
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template arguments or priorities --- just some bits of literal
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syntax. The following example illustrates this idea idea by
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associating common symbols with the constructors of a datatype.
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*}
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datatype currency =
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Euro nat ("\<euro>")
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| Pounds nat ("\<pounds>")
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| Yen nat ("\<yen>")
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| Dollar nat ("$")
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text {*
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\noindent Here the mixfix annotations on the rightmost column happen
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to consist of a single Isabelle symbol each: \verb,\,\verb,<euro>,,
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\verb,\,\verb,<pounds>,, \verb,\,\verb,<yen>,, and \verb,$,. Recall
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that a constructor like @{text Euro} actually is a function @{typ
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"nat \<Rightarrow> currency"}. The expression @{text "Euro 10"} will be
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printed as @{term "\<euro> 10"}; only the head of the application is
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subject to our concrete syntax. This rather simple form already
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achieves conformance with notational standards of the European
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Commission.
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Prefix syntax also works for plain \isakeyword{consts} or
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\isakeyword{constdefs}, of course.
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*}
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subsection {* Syntax Translations \label{sec:syntax-translations} *}
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text{*
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Mixfix syntax annotations work well in those situations where
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particular constant application forms need to be decorated by
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concrete syntax; e.g.\ @{text "xor A B"} versus @{text "A \<oplus> B"}
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covered before. Occasionally the relationship between some piece of
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notation and its internal form is slightly more involved. Here the
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concept of \bfindex{syntax translations} enters the scene.
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Using the raw \isakeyword{syntax}\index{syntax (command)} command we
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may introduce uninterpreted notational elements, while
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\commdx{translations} relate input forms with more complex logical
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expressions. This essentially provides a simple mechanism for
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syntactic macros; even heavier transformations may be written in ML
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\cite{isabelle-ref}.
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\medskip A typical example of syntax translations is to decorate
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relational expressions (set-membership of tuples) with symbolic
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notation, e.g.\ @{text "(x, y) \<in> sim"} versus @{text "x \<approx> y"}.
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*}
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consts
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sim :: "('a \<times> 'a) set"
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syntax
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"_sim" :: "'a \<Rightarrow> 'a \<Rightarrow> bool" (infix "\<approx>" 50)
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translations
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"x \<approx> y" \<rightleftharpoons> "(x, y) \<in> sim"
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text {*
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\noindent Here the name of the dummy constant @{text "_sim"} does
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not really matter, as long as it is not used elsewhere. Prefixing
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an underscore is a common convention. The \isakeyword{translations}
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declaration already uses concrete syntax on the left-hand side;
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internally we relate a raw application @{text "_sim x y"} with
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@{text "(x, y) \<in> sim"}.
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\medskip Another common application of syntax translations is to
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provide variant versions of fundamental relational expressions, such
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as @{text \<noteq>} for negated equalities. The following declaration
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stems from Isabelle/HOL itself:
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*}
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syntax "_not_equal" :: "'a \<Rightarrow> 'a \<Rightarrow> bool" (infixl "\<noteq>\<ignore>" 50)
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translations "x \<noteq>\<ignore> y" \<rightleftharpoons> "\<not> (x = y)"
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text {*
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\noindent Normally one would introduce derived concepts like this
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within the logic, using \isakeyword{consts} + \isakeyword{defs}
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instead of \isakeyword{syntax} + \isakeyword{translations}. The
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present formulation has the virtue that expressions are immediately
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replaced by the ``definition'' upon parsing; the effect is reversed
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upon printing.
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Simulating definitions via translations is adequate for very basic
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principles, where a new representation is a trivial variation on an
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existing one. On the other hand, syntax translations do not scale
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up well to large hierarchies of concepts built on each other.
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*}
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section {* Document Preparation \label{sec:document-preparation} *}
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text {*
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Isabelle/Isar is centered around the concept of \bfindex{formal
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proof documents}\index{documents|bold}. The ultimate result of a
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formal development effort is meant to be a human-readable record,
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presented as browsable PDF file or printed on paper. The overall
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document structure follows traditional mathematical articles, with
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sections, intermediate explanations, definitions, theorems and
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proofs.
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\medskip The Isabelle document preparation system essentially acts
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as a front-end to {\LaTeX}. After checking specifications and
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proofs formally, the theory sources are turned into typesetting
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instructions in a schematic manner. This enables users to write
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authentic reports on theory developments with little effort --- many
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technical consistency checks are handled by the system.
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Here is an example to illustrate the idea of Isabelle document
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preparation.
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*}
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text_raw {* \begin{quotation} *}
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text {*
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The following datatype definition of @{text "'a bintree"} models
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binary trees with nodes being decorated by elements of type @{typ
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'a}.
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*}
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datatype 'a bintree =
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Leaf | Branch 'a "'a bintree" "'a bintree"
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text {*
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\noindent The datatype induction rule generated here is of the form
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@{thm [indent = 1, display] bintree.induct [no_vars]}
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*}
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text_raw {* \end{quotation} *}
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text {*
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The above document output has been produced by the following theory
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specification:
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\begin{ttbox}
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text {\ttlbrace}*
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The following datatype definition of {\at}{\ttlbrace}text "'a bintree"{\ttrbrace}
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models binary trees with nodes being decorated by elements
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of type {\at}{\ttlbrace}typ 'a{\ttrbrace}.
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*{\ttrbrace}
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datatype 'a bintree =
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Leaf | Branch 'a "'a bintree" "'a bintree"
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text {\ttlbrace}*
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{\ttback}noindent The datatype induction rule generated here is
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of the form {\at}{\ttlbrace}thm [display] bintree.induct [no_vars]{\ttrbrace}
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*{\ttrbrace}
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\end{ttbox}
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\noindent Here we have augmented the theory by formal comments
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(using \isakeyword{text} blocks). The informal parts may again
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refer to formal entities by means of ``antiquotations'' (such as
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\texttt{\at}\verb,{text "'a bintree"}, or
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\texttt{\at}\verb,{typ 'a},), see also \S\ref{sec:doc-prep-text}.
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*}
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subsection {* Isabelle Sessions *}
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text {*
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In contrast to the highly interactive mode of Isabelle/Isar theory
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development, the document preparation stage essentially works in
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batch-mode. An Isabelle \bfindex{session} consists of a collection
|
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|
355 |
of source files that may contribute to an output document
|
12681
|
356 |
eventually. Each session is derived from a single parent, usually
|
|
357 |
an object-logic image like \texttt{HOL}. This results in an overall
|
|
358 |
tree structure, which is reflected by the output location in the
|
|
359 |
file system (usually rooted at \verb,~/isabelle/browser_info,).
|
12645
|
360 |
|
12683
|
361 |
\medskip The easiest way to manage Isabelle sessions is via
|
12685
|
362 |
\texttt{isatool mkdir} (generates an initial session source setup)
|
|
363 |
and \texttt{isatool make} (run sessions controlled by
|
12683
|
364 |
\texttt{IsaMakefile}). For example, a new session
|
|
365 |
\texttt{MySession} derived from \texttt{HOL} may be produced as
|
|
366 |
follows:
|
|
367 |
|
|
368 |
\begin{verbatim}
|
|
369 |
isatool mkdir HOL MySession
|
|
370 |
isatool make
|
|
371 |
\end{verbatim}
|
|
372 |
|
12685
|
373 |
The \texttt{isatool make} job also informs about the file-system
|
|
374 |
location of the ultimate results. The above dry run should be able
|
|
375 |
to produce some \texttt{document.pdf} (with dummy title, empty table
|
12743
|
376 |
of contents etc.). Any failure at this stage usually indicates
|
12685
|
377 |
technical problems of the {\LaTeX} installation.\footnote{Especially
|
|
378 |
make sure that \texttt{pdflatex} is present; if all fails one may
|
|
379 |
fall back on DVI output by changing \texttt{usedir} options in
|
|
380 |
\texttt{IsaMakefile} \cite{isabelle-sys}.}
|
12683
|
381 |
|
|
382 |
\medskip The detailed arrangement of the session sources is as
|
12746
|
383 |
follows.
|
12645
|
384 |
|
|
385 |
\begin{itemize}
|
|
386 |
|
12670
|
387 |
\item Directory \texttt{MySession} holds the required theory files
|
|
388 |
$T@1$\texttt{.thy}, \dots, $T@n$\texttt{.thy}.
|
12645
|
389 |
|
|
390 |
\item File \texttt{MySession/ROOT.ML} holds appropriate ML commands
|
|
391 |
for loading all wanted theories, usually just
|
12665
|
392 |
``\texttt{use_thy"$T@i$";}'' for any $T@i$ in leaf position of the
|
12670
|
393 |
dependency graph.
|
12645
|
394 |
|
|
395 |
\item Directory \texttt{MySession/document} contains everything
|
12653
|
396 |
required for the {\LaTeX} stage; only \texttt{root.tex} needs to be
|
|
397 |
provided initially.
|
12645
|
398 |
|
12653
|
399 |
The latter file holds appropriate {\LaTeX} code to commence a
|
|
400 |
document (\verb,\documentclass, etc.), and to include the generated
|
12743
|
401 |
files $T@i$\texttt{.tex} for each theory. Isabelle will generate a
|
|
402 |
file \texttt{session.tex} holding {\LaTeX} commands to include all
|
12746
|
403 |
generated theory output files in topologically sorted order, so
|
|
404 |
\verb,\input{session}, in the body of \texttt{root.tex} does the job
|
|
405 |
in most situations.
|
12653
|
406 |
|
12681
|
407 |
\item \texttt{IsaMakefile} holds appropriate dependencies and
|
|
408 |
invocations of Isabelle tools to control the batch job. In fact,
|
12746
|
409 |
several sessions may be managed by the same \texttt{IsaMakefile}.
|
12681
|
410 |
See also \cite{isabelle-sys} for further details, especially on
|
12653
|
411 |
\texttt{isatool usedir} and \texttt{isatool make}.
|
12645
|
412 |
|
|
413 |
\end{itemize}
|
|
414 |
|
12685
|
415 |
One may now start to populate the directory \texttt{MySession}, and
|
|
416 |
the file \texttt{MySession/ROOT.ML} accordingly.
|
|
417 |
\texttt{MySession/document/root.tex} should also be adapted at some
|
|
418 |
point; the default version is mostly self-explanatory. Note that
|
|
419 |
\verb,\isabellestyle, enables fine-tuning of the general appearance
|
|
420 |
of characters and mathematical symbols (see also
|
|
421 |
\S\ref{sec:doc-prep-symbols}).
|
12653
|
422 |
|
12685
|
423 |
Especially observe the included {\LaTeX} packages \texttt{isabelle}
|
|
424 |
(mandatory), \texttt{isabellesym} (required for mathematical
|
12743
|
425 |
symbols), and the final \texttt{pdfsetup} (provides sane defaults
|
|
426 |
for \texttt{hyperref}, including URL markup) --- all three are
|
|
427 |
distributed with Isabelle. Further packages may be required in
|
12685
|
428 |
particular applications, e.g.\ for unusual mathematical symbols.
|
12645
|
429 |
|
12746
|
430 |
\medskip Any additional files for the {\LaTeX} stage go into the
|
|
431 |
\texttt{MySession/document} directory as well. In particular,
|
|
432 |
adding \texttt{root.bib} (with that specific name) causes an
|
|
433 |
automatic run of \texttt{bibtex} to process a bibliographic
|
|
434 |
database; see also \texttt{isatool document} in \cite{isabelle-sys}.
|
12645
|
435 |
|
12653
|
436 |
\medskip Any failure of the document preparation phase in an
|
12670
|
437 |
Isabelle batch session leaves the generated sources in their target
|
|
438 |
location (as pointed out by the accompanied error message). This
|
12746
|
439 |
enables users to trace {\LaTeX} problems with the generated files at
|
12685
|
440 |
hand.
|
12645
|
441 |
*}
|
|
442 |
|
|
443 |
|
12648
|
444 |
subsection {* Structure Markup *}
|
12645
|
445 |
|
12653
|
446 |
text {*
|
|
447 |
The large-scale structure of Isabelle documents follows existing
|
|
448 |
{\LaTeX} conventions, with chapters, sections, subsubsections etc.
|
|
449 |
The Isar language includes separate \bfindex{markup commands}, which
|
12681
|
450 |
do not affect the formal meaning of a theory (or proof), but result
|
12665
|
451 |
in corresponding {\LaTeX} elements.
|
12645
|
452 |
|
12665
|
453 |
There are separate markup commands depending on the textual context:
|
|
454 |
in header position (just before \isakeyword{theory}), within the
|
|
455 |
theory body, or within a proof. The header needs to be treated
|
|
456 |
specially here, since ordinary theory and proof commands may only
|
|
457 |
occur \emph{after} the initial \isakeyword{theory} specification.
|
12645
|
458 |
|
12665
|
459 |
\medskip
|
12645
|
460 |
|
|
461 |
\begin{tabular}{llll}
|
|
462 |
header & theory & proof & default meaning \\\hline
|
|
463 |
& \commdx{chapter} & & \verb,\chapter, \\
|
|
464 |
\commdx{header} & \commdx{section} & \commdx{sect} & \verb,\section, \\
|
|
465 |
& \commdx{subsection} & \commdx{subsect} & \verb,\subsection, \\
|
|
466 |
& \commdx{subsubsection} & \commdx{subsubsect} & \verb,\subsubsection, \\
|
|
467 |
\end{tabular}
|
|
468 |
|
|
469 |
\medskip
|
|
470 |
|
|
471 |
From the Isabelle perspective, each markup command takes a single
|
12746
|
472 |
$text$ argument (delimited by \verb,",~@{text \<dots>}~\verb,", or
|
|
473 |
\verb,{,\verb,*,~@{text \<dots>}~\verb,*,\verb,},). After stripping any
|
12645
|
474 |
surrounding white space, the argument is passed to a {\LaTeX} macro
|
12653
|
475 |
\verb,\isamarkupXYZ, for any command \isakeyword{XYZ}. These macros
|
|
476 |
are defined in \verb,isabelle.sty, according to the meaning given in
|
|
477 |
the rightmost column above.
|
12645
|
478 |
|
|
479 |
\medskip The following source fragment illustrates structure markup
|
12653
|
480 |
of a theory. Note that {\LaTeX} labels may be included inside of
|
|
481 |
section headings as well.
|
12645
|
482 |
|
|
483 |
\begin{ttbox}
|
|
484 |
header {\ttlbrace}* Some properties of Foo Bar elements *{\ttrbrace}
|
|
485 |
|
|
486 |
theory Foo_Bar = Main:
|
|
487 |
|
|
488 |
subsection {\ttlbrace}* Basic definitions *{\ttrbrace}
|
|
489 |
|
|
490 |
consts
|
|
491 |
foo :: \dots
|
|
492 |
bar :: \dots
|
12648
|
493 |
|
12645
|
494 |
defs \dots
|
12648
|
495 |
|
12645
|
496 |
subsection {\ttlbrace}* Derived rules *{\ttrbrace}
|
|
497 |
|
|
498 |
lemma fooI: \dots
|
|
499 |
lemma fooE: \dots
|
|
500 |
|
12648
|
501 |
subsection {\ttlbrace}* Main theorem {\ttback}label{\ttlbrace}sec:main-theorem{\ttrbrace} *{\ttrbrace}
|
12645
|
502 |
|
|
503 |
theorem main: \dots
|
|
504 |
|
|
505 |
end
|
|
506 |
\end{ttbox}
|
|
507 |
|
12653
|
508 |
Users may occasionally want to change the meaning of markup
|
12665
|
509 |
commands, say via \verb,\renewcommand, in \texttt{root.tex};
|
12670
|
510 |
\verb,\isamarkupheader, is a good candidate for some tuning, e.g.\
|
12653
|
511 |
moving it up in the hierarchy to become \verb,\chapter,.
|
12645
|
512 |
|
|
513 |
\begin{verbatim}
|
|
514 |
\renewcommand{\isamarkupheader}[1]{\chapter{#1}}
|
|
515 |
\end{verbatim}
|
|
516 |
|
12744
|
517 |
\noindent That particular modification requires change to the
|
|
518 |
document class given in \texttt{root.tex} to something that supports
|
|
519 |
the notion of chapters in the first place, such as
|
|
520 |
\verb,\documentclass{report},.
|
12645
|
521 |
|
12648
|
522 |
\medskip The {\LaTeX} macro \verb,\isabellecontext, is maintained to
|
|
523 |
hold the name of the current theory context. This is particularly
|
12653
|
524 |
useful for document headings:
|
12645
|
525 |
|
|
526 |
\begin{verbatim}
|
12653
|
527 |
\renewcommand{\isamarkupheader}[1]
|
12645
|
528 |
{\chapter{#1}\markright{THEORY~\isabellecontext}}
|
|
529 |
\end{verbatim}
|
|
530 |
|
|
531 |
\noindent Make sure to include something like
|
12648
|
532 |
\verb,\pagestyle{headings}, in \texttt{root.tex}; the document
|
|
533 |
should have more than 2 pages to show the effect.
|
12645
|
534 |
*}
|
|
535 |
|
|
536 |
|
12744
|
537 |
subsection {* Formal Comments and Antiquotations \label{sec:doc-prep-text} *}
|
12645
|
538 |
|
|
539 |
text {*
|
12744
|
540 |
Isabelle \bfindex{source comments}, which are of the form
|
12746
|
541 |
\verb,(,\verb,*,~@{text \<dots>}~\verb,*,\verb,),, essentially act like
|
|
542 |
white space and do not really contribute to the content. They
|
|
543 |
mainly serve technical purposes to mark certain oddities in the raw
|
|
544 |
input text. In contrast, \bfindex{formal comments} are portions of
|
|
545 |
text that are associated with formal Isabelle/Isar commands
|
12681
|
546 |
(\bfindex{marginal comments}), or as standalone paragraphs within a
|
12665
|
547 |
theory or proof context (\bfindex{text blocks}).
|
12659
|
548 |
|
|
549 |
\medskip Marginal comments are part of each command's concrete
|
12670
|
550 |
syntax \cite{isabelle-ref}; the common form is ``\verb,--,~$text$''
|
12746
|
551 |
where $text$ is delimited by \verb,",@{text \<dots>}\verb,", or
|
|
552 |
\verb,{,\verb,*,~@{text \<dots>}~\verb,*,\verb,}, as before. Multiple
|
12670
|
553 |
marginal comments may be given at the same time. Here is a simple
|
|
554 |
example:
|
12665
|
555 |
*}
|
|
556 |
|
|
557 |
lemma "A --> A"
|
|
558 |
-- "a triviality of propositional logic"
|
|
559 |
-- "(should not really bother)"
|
|
560 |
by (rule impI) -- "implicit assumption step involved here"
|
|
561 |
|
|
562 |
text {*
|
|
563 |
\noindent The above output has been produced as follows:
|
12659
|
564 |
|
|
565 |
\begin{verbatim}
|
|
566 |
lemma "A --> A"
|
|
567 |
-- "a triviality of propositional logic"
|
|
568 |
-- "(should not really bother)"
|
|
569 |
by (rule impI) -- "implicit assumption step involved here"
|
|
570 |
\end{verbatim}
|
|
571 |
|
12670
|
572 |
From the {\LaTeX} viewpoint, ``\verb,--,'' acts like a markup
|
|
573 |
command, associated with the macro \verb,\isamarkupcmt, (taking a
|
|
574 |
single argument).
|
12659
|
575 |
|
12665
|
576 |
\medskip Text blocks are introduced by the commands \bfindex{text}
|
|
577 |
and \bfindex{txt}, for theory and proof contexts, respectively.
|
|
578 |
Each takes again a single $text$ argument, which is interpreted as a
|
|
579 |
free-form paragraph in {\LaTeX} (surrounded by some additional
|
12670
|
580 |
vertical space). This behavior may be changed by redefining the
|
|
581 |
{\LaTeX} environments of \verb,isamarkuptext, or
|
|
582 |
\verb,isamarkuptxt,, respectively (via \verb,\renewenvironment,) The
|
|
583 |
text style of the body is determined by \verb,\isastyletext, and
|
|
584 |
\verb,\isastyletxt,; the default setup uses a smaller font within
|
12746
|
585 |
proofs. This may be changed as follows:
|
|
586 |
|
|
587 |
\begin{verbatim}
|
|
588 |
\renewcommand{\isastyletxt}{\isastyletext}
|
|
589 |
\end{verbatim}
|
12659
|
590 |
|
|
591 |
\medskip The $text$ part of each of the various markup commands
|
12670
|
592 |
considered so far essentially inserts \emph{quoted material} into a
|
|
593 |
formal text, mainly for instruction of the reader. An
|
|
594 |
\bfindex{antiquotation} is again a formal object embedded into such
|
|
595 |
an informal portion. The interpretation of antiquotations is
|
|
596 |
limited to some well-formedness checks, with the result being pretty
|
12746
|
597 |
printed to the resulting document. Quoted text blocks together with
|
|
598 |
antiquotations provide very useful means to reference formal
|
|
599 |
entities, with good confidence in getting the technical details
|
|
600 |
right (especially syntax and types).
|
12659
|
601 |
|
12665
|
602 |
The general syntax of antiquotations is as follows:
|
12659
|
603 |
\texttt{{\at}{\ttlbrace}$name$ $arguments${\ttrbrace}}, or
|
|
604 |
\texttt{{\at}{\ttlbrace}$name$ [$options$] $arguments${\ttrbrace}}
|
12665
|
605 |
for a comma-separated list of options consisting of a $name$ or
|
12670
|
606 |
\texttt{$name$=$value$}. The syntax of $arguments$ depends on the
|
|
607 |
kind of antiquotation, it generally follows the same conventions for
|
|
608 |
types, terms, or theorems as in the formal part of a theory.
|
12645
|
609 |
|
12665
|
610 |
\medskip Here is an example of the quotation-antiquotation
|
12659
|
611 |
technique: @{term "%x y. x"} is a well-typed term.
|
|
612 |
|
12665
|
613 |
\medskip\noindent The above output has been produced as follows:
|
12659
|
614 |
\begin{ttbox}
|
|
615 |
text {\ttlbrace}*
|
12665
|
616 |
Here is an example of the quotation-antiquotation technique:
|
12659
|
617 |
{\at}{\ttlbrace}term "%x y. x"{\ttrbrace} is a well-typed term.
|
|
618 |
*{\ttrbrace}
|
|
619 |
\end{ttbox}
|
|
620 |
|
|
621 |
From the notational change of the ASCII character \verb,%, to the
|
|
622 |
symbol @{text \<lambda>} we see that the term really got printed by the
|
12670
|
623 |
system (after parsing and type-checking) --- document preparation
|
12665
|
624 |
enables symbolic output by default.
|
12659
|
625 |
|
12665
|
626 |
\medskip The next example includes an option to modify the
|
|
627 |
\verb,show_types, flag of Isabelle:
|
12659
|
628 |
\texttt{{\at}}\verb,{term [show_types] "%x y. x"}, produces @{term
|
12670
|
629 |
[show_types] "%x y. x"}. Type-inference has figured out the most
|
|
630 |
general typings in the present (theory) context. Note that term
|
|
631 |
fragments may acquire different typings due to constraints imposed
|
|
632 |
by previous text (say within a proof), e.g.\ due to the main goal
|
|
633 |
statement given beforehand.
|
12659
|
634 |
|
|
635 |
\medskip Several further kinds of antiquotations (and options) are
|
12665
|
636 |
available \cite{isabelle-sys}. Here are a few commonly used
|
12670
|
637 |
combinations:
|
12659
|
638 |
|
|
639 |
\medskip
|
12651
|
640 |
|
12659
|
641 |
\begin{tabular}{ll}
|
|
642 |
\texttt{\at}\verb,{typ,~$\tau$\verb,}, & print type $\tau$ \\
|
|
643 |
\texttt{\at}\verb,{term,~$t$\verb,}, & print term $t$ \\
|
|
644 |
\texttt{\at}\verb,{prop,~$\phi$\verb,}, & print proposition $\phi$ \\
|
12665
|
645 |
\texttt{\at}\verb,{prop [display],~$\phi$\verb,}, & print large proposition $\phi$ (with linebreaks) \\
|
12659
|
646 |
\texttt{\at}\verb,{prop [source],~$\phi$\verb,}, & check proposition $\phi$, print its input \\
|
|
647 |
\texttt{\at}\verb,{thm,~$a$\verb,}, & print fact $a$ \\
|
|
648 |
\texttt{\at}\verb,{thm,~$a$~\verb,[no_vars]}, & print fact $a$, fixing schematic variables \\
|
12746
|
649 |
\texttt{\at}\verb,{thm [source],~$a$\verb,}, & check availability of fact $a$, print its name \\
|
12659
|
650 |
\texttt{\at}\verb,{text,~$s$\verb,}, & print uninterpreted text $s$ \\
|
|
651 |
\end{tabular}
|
|
652 |
|
|
653 |
\medskip
|
|
654 |
|
12665
|
655 |
Note that \attrdx{no_vars} given above is \emph{not} an
|
|
656 |
antiquotation option, but an attribute of the theorem argument given
|
|
657 |
here. This might be useful with a diagnostic command like
|
|
658 |
\isakeyword{thm}, too.
|
12659
|
659 |
|
12665
|
660 |
\medskip The \texttt{\at}\verb,{text, $s$\verb,}, antiquotation is
|
12659
|
661 |
particularly interesting. Embedding uninterpreted text within an
|
12665
|
662 |
informal body might appear useless at first sight. Here the key
|
|
663 |
virtue is that the string $s$ is processed as Isabelle output,
|
|
664 |
interpreting Isabelle symbols appropriately.
|
12659
|
665 |
|
12665
|
666 |
For example, \texttt{\at}\verb,{text "\<forall>\<exists>"}, produces @{text
|
|
667 |
"\<forall>\<exists>"}, according to the standard interpretation of these symbol
|
|
668 |
(cf.\ \S\ref{sec:doc-prep-symbols}). Thus we achieve consistent
|
12659
|
669 |
mathematical notation in both the formal and informal parts of the
|
12665
|
670 |
document very easily. Manual {\LaTeX} code would leave more control
|
12681
|
671 |
over the typesetting, but is also slightly more tedious.
|
12645
|
672 |
*}
|
|
673 |
|
|
674 |
|
12674
|
675 |
subsection {* Interpretation of Symbols \label{sec:doc-prep-symbols} *}
|
12645
|
676 |
|
|
677 |
text {*
|
12665
|
678 |
As has been pointed out before (\S\ref{sec:syntax-symbols}),
|
12670
|
679 |
Isabelle symbols are the smallest syntactic entities --- a
|
12681
|
680 |
straightforward generalization of ASCII characters. While Isabelle
|
12665
|
681 |
does not impose any interpretation of the infinite collection of
|
12670
|
682 |
named symbols, {\LaTeX} documents show canonical glyphs for certain
|
|
683 |
standard symbols \cite[appendix~A]{isabelle-sys}.
|
12659
|
684 |
|
12665
|
685 |
The {\LaTeX} code produced from Isabelle text follows a relatively
|
12670
|
686 |
simple scheme. Users may wish to tune the final appearance by
|
|
687 |
redefining certain macros, say in \texttt{root.tex} of the document.
|
|
688 |
|
|
689 |
\begin{enumerate}
|
12659
|
690 |
|
12670
|
691 |
\item 7-bit ASCII characters: letters \texttt{A\dots Z} and
|
12746
|
692 |
\texttt{a\dots z} are output directly, digits are passed as an
|
12670
|
693 |
argument to the \verb,\isadigit, macro, other characters are
|
|
694 |
replaced by specifically named macros of the form
|
12665
|
695 |
\verb,\isacharXYZ,.
|
12659
|
696 |
|
12746
|
697 |
\item Named symbols: \verb,\,\verb,<,$XYZ$\verb,>, is turned into
|
|
698 |
\verb,{\isasym,$XYZ$\verb,},; note the additional braces.
|
12659
|
699 |
|
12746
|
700 |
\item Named control symbols: \verb,\,\verb,<^,$XYZ$\verb,>, is
|
|
701 |
turned into \verb,\isactrl,$XYZ$; subsequent symbols may act as
|
|
702 |
arguments if the corresponding macro is defined accordingly.
|
12670
|
703 |
|
12659
|
704 |
\end{enumerate}
|
12665
|
705 |
|
12670
|
706 |
Users may occasionally wish to give new {\LaTeX} interpretations of
|
|
707 |
named symbols; this merely requires an appropriate definition of
|
12746
|
708 |
\verb,\isasym,$XYZ$\verb,, for \verb,\,\verb,<,$XYZ$\verb,>, (see
|
|
709 |
\texttt{isabelle.sty} for working examples). Control symbols are
|
|
710 |
slightly more difficult to get right, though.
|
12665
|
711 |
|
|
712 |
\medskip The \verb,\isabellestyle, macro provides a high-level
|
|
713 |
interface to tune the general appearance of individual symbols. For
|
12670
|
714 |
example, \verb,\isabellestyle{it}, uses the italics text style to
|
|
715 |
mimic the general appearance of the {\LaTeX} math mode; double
|
12743
|
716 |
quotes are not printed at all. The resulting quality of typesetting
|
|
717 |
is quite good, so this should be the default style for work that
|
|
718 |
gets distributed to a broader audience.
|
12645
|
719 |
*}
|
|
720 |
|
|
721 |
|
12653
|
722 |
subsection {* Suppressing Output \label{sec:doc-prep-suppress} *}
|
12645
|
723 |
|
|
724 |
text {*
|
12670
|
725 |
By default, Isabelle's document system generates a {\LaTeX} source
|
12743
|
726 |
file for each theory that gets loaded while running the session.
|
|
727 |
The generated \texttt{session.tex} will include all of these in
|
|
728 |
order of appearance, which in turn gets included by the standard
|
|
729 |
\texttt{root.tex}. Certainly one may change the order or suppress
|
12746
|
730 |
unwanted theories by ignoring \texttt{session.tex} and load
|
|
731 |
individual files directly in \texttt{root.tex}. On the other hand,
|
|
732 |
such an arrangement requires additional maintenance whenever the
|
|
733 |
collection of theories changes.
|
12648
|
734 |
|
|
735 |
Alternatively, one may tune the theory loading process in
|
12653
|
736 |
\texttt{ROOT.ML} itself: traversal of the theory dependency graph
|
12670
|
737 |
may be fine-tuned by adding \verb,use_thy, invocations, although
|
|
738 |
topological sorting still has to be observed. Moreover, the ML
|
|
739 |
operator \verb,no_document, temporarily disables document generation
|
|
740 |
while executing a theory loader command; its usage is like this:
|
12648
|
741 |
|
|
742 |
\begin{verbatim}
|
12665
|
743 |
no_document use_thy "T";
|
12648
|
744 |
\end{verbatim}
|
12645
|
745 |
|
12681
|
746 |
\medskip Theory output may also be suppressed in smaller portions.
|
12670
|
747 |
For example, research articles, or slides usually do not include the
|
|
748 |
formal content in full. In order to delimit \bfindex{ignored
|
12653
|
749 |
material} special source comments
|
12648
|
750 |
\verb,(,\verb,*,\verb,<,\verb,*,\verb,), and
|
12653
|
751 |
\verb,(,\verb,*,\verb,>,\verb,*,\verb,), may be included in the
|
|
752 |
text. Only the document preparation system is affected, the formal
|
12746
|
753 |
checking of the theory is performed unchanged.
|
12648
|
754 |
|
12746
|
755 |
In the subsequent example we suppress the slightly formalistic
|
12653
|
756 |
\isakeyword{theory} + \isakeyword{end} surroundings a theory.
|
12648
|
757 |
|
|
758 |
\medskip
|
|
759 |
|
|
760 |
\begin{tabular}{l}
|
|
761 |
\verb,(,\verb,*,\verb,<,\verb,*,\verb,), \\
|
12665
|
762 |
\texttt{theory T = Main:} \\
|
12648
|
763 |
\verb,(,\verb,*,\verb,>,\verb,*,\verb,), \\
|
|
764 |
~~$\vdots$ \\
|
|
765 |
\verb,(,\verb,*,\verb,<,\verb,*,\verb,), \\
|
|
766 |
\texttt{end} \\
|
|
767 |
\verb,(,\verb,*,\verb,>,\verb,*,\verb,), \\
|
|
768 |
\end{tabular}
|
|
769 |
|
|
770 |
\medskip
|
|
771 |
|
12681
|
772 |
Text may be suppressed in a fine-grained manner. We may even drop
|
12746
|
773 |
vital parts of a proof, pretending that things have been simpler
|
|
774 |
than in reality. For example, this ``fully automatic'' proof is
|
|
775 |
actually a fake:
|
12651
|
776 |
*}
|
|
777 |
|
|
778 |
lemma "x \<noteq> (0::int) \<Longrightarrow> 0 < x * x"
|
|
779 |
by (auto(*<*)simp add: int_less_le(*>*))
|
|
780 |
|
|
781 |
text {*
|
|
782 |
\noindent Here the real source of the proof has been as follows:
|
|
783 |
|
|
784 |
\begin{verbatim}
|
|
785 |
by (auto(*<*)simp add: int_less_le(*>*))
|
12659
|
786 |
\end{verbatim}
|
|
787 |
%(*
|
12651
|
788 |
|
12681
|
789 |
\medskip Ignoring portions of printed text does demand some care by
|
12746
|
790 |
the writer. First of all, the user is responsible not to obfuscate
|
|
791 |
the underlying theory development in an unduly manner. It is fairly
|
|
792 |
easy to invalidate the visible text, e.g.\ by referencing
|
|
793 |
questionable formal items (strange definitions, arbitrary axioms
|
|
794 |
etc.) that have been hidden from sight beforehand.
|
12651
|
795 |
|
12746
|
796 |
Authentic reports of Isabelle/Isar theories, say as part of a
|
|
797 |
library, should refrain from suppressing parts of the text at all.
|
|
798 |
Other users may need the full information for their own derivative
|
|
799 |
work. If a particular formalization appears inadequate for general
|
|
800 |
public coverage, it is often more appropriate to think of a better
|
|
801 |
way in the first place.
|
12670
|
802 |
|
|
803 |
\medskip Some technical subtleties of the
|
12665
|
804 |
\verb,(,\verb,*,\verb,<,\verb,*,\verb,),~\verb,(,\verb,*,\verb,>,\verb,*,\verb,),
|
12670
|
805 |
elements need to be kept in mind, too --- the system performs little
|
|
806 |
sanity checks here. Arguments of markup commands and formal
|
12651
|
807 |
comments must not be hidden, otherwise presentation fails. Open and
|
|
808 |
close parentheses need to be inserted carefully; it is fairly easy
|
12653
|
809 |
to hide the wrong parts, especially after rearranging the sources.
|
12651
|
810 |
|
12629
|
811 |
*}
|
|
812 |
|
11647
|
813 |
(*<*)
|
|
814 |
end
|
|
815 |
(*>*)
|