
diff -r 2775062fd3a9 -r 2f4684e2ea95 doc-src/Codegen/Thy/document/Further.tex
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/doc-src/Codegen/Thy/document/Further.tex	Tue Mar 03 11:00:51 2009 +0100
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+%
+\begin{isabellebody}%
+\def\isabellecontext{Further}%
+%
+\isadelimtheory
+%
+\endisadelimtheory
+%
+\isatagtheory
+\isacommand{theory}\isamarkupfalse%
+\ Further\isanewline
+\isakeyword{imports}\ Setup\isanewline
+\isakeyword{begin}%
+\endisatagtheory
+{\isafoldtheory}%
+%
+\isadelimtheory
+%
+\endisadelimtheory
+%
+\isamarkupsection{Further issues \label{sec:further}%
+}
+\isamarkuptrue%
+%
+\isamarkupsubsection{Further reading%
+}
+\isamarkuptrue%
+%
+\begin{isamarkuptext}%
+Do dive deeper into the issue of code generation, you should visit
+  the Isabelle/Isar Reference Manual \cite{isabelle-isar-ref} which
+  contains exhaustive syntax diagrams.%
+\end{isamarkuptext}%
+\isamarkuptrue%
+%
+\isamarkupsubsection{Modules%
+}
+\isamarkuptrue%
+%
+\begin{isamarkuptext}%
+When invoking the \hyperlink{command.export-code}{\mbox{\isa{\isacommand{export{\isacharunderscore}code}}}} command it is possible to leave
+  out the \hyperlink{keyword.module-name}{\mbox{\isa{\isakeyword{module{\isacharunderscore}name}}}} part;  then code is distributed over
+  different modules, where the module name space roughly is induced
+  by the \isa{Isabelle} theory name space.
+
+  Then sometimes the awkward situation occurs that dependencies between
+  definitions introduce cyclic dependencies between modules, which in the
+  \isa{Haskell} world leaves you to the mercy of the \isa{Haskell} implementation
+  you are using,  while for \isa{SML}/\isa{OCaml} code generation is not possible.
+
+  A solution is to declare module names explicitly.
+  Let use assume the three cyclically dependent
+  modules are named \emph{A}, \emph{B} and \emph{C}.
+  Then, by stating%
+\end{isamarkuptext}%
+\isamarkuptrue%
+%
+\isadelimquote
+%
+\endisadelimquote
+%
+\isatagquote
+\isacommand{code{\isacharunderscore}modulename}\isamarkupfalse%
+\ SML\isanewline
+\ \ A\ ABC\isanewline
+\ \ B\ ABC\isanewline
+\ \ C\ ABC%
+\endisatagquote
+{\isafoldquote}%
+%
+\isadelimquote
+%
+\endisadelimquote
+%
+\begin{isamarkuptext}%
+we explicitly map all those modules on \emph{ABC},
+  resulting in an ad-hoc merge of this three modules
+  at serialisation time.%
+\end{isamarkuptext}%
+\isamarkuptrue%
+%
+\isamarkupsubsection{Evaluation oracle%
+}
+\isamarkuptrue%
+%
+\begin{isamarkuptext}%
+Code generation may also be used to \emph{evaluate} expressions
+  (using \isa{SML} as target language of course).
+  For instance, the \hyperlink{command.value}{\mbox{\isa{\isacommand{value}}}} allows to reduce an expression to a
+  normal form with respect to the underlying code equations:%
+\end{isamarkuptext}%
+\isamarkuptrue%
+%
+\isadelimquote
+%
+\endisadelimquote
+%
+\isatagquote
+\isacommand{value}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isadigit{4}}{\isadigit{2}}\ {\isacharslash}\ {\isacharparenleft}{\isadigit{1}}{\isadigit{2}}\ {\isacharcolon}{\isacharcolon}\ rat{\isacharparenright}{\isachardoublequoteclose}%
+\endisatagquote
+{\isafoldquote}%
+%
+\isadelimquote
+%
+\endisadelimquote
+%
+\begin{isamarkuptext}%
+\noindent will display \isa{{\isadigit{7}}\ {\isacharslash}\ {\isadigit{2}}}.
+
+  The \hyperlink{method.eval}{\mbox{\isa{eval}}} method tries to reduce a goal by code generation to \isa{True}
+  and solves it in that case, but fails otherwise:%
+\end{isamarkuptext}%
+\isamarkuptrue%
+%
+\isadelimquote
+%
+\endisadelimquote
+%
+\isatagquote
+\isacommand{lemma}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isadigit{4}}{\isadigit{2}}\ {\isacharslash}\ {\isacharparenleft}{\isadigit{1}}{\isadigit{2}}\ {\isacharcolon}{\isacharcolon}\ rat{\isacharparenright}\ {\isacharequal}\ {\isadigit{7}}\ {\isacharslash}\ {\isadigit{2}}{\isachardoublequoteclose}\isanewline
+\ \ \isacommand{by}\isamarkupfalse%
+\ eval%
+\endisatagquote
+{\isafoldquote}%
+%
+\isadelimquote
+%
+\endisadelimquote
+%
+\begin{isamarkuptext}%
+\noindent The soundness of the \hyperlink{method.eval}{\mbox{\isa{eval}}} method depends crucially 
+  on the correctness of the code generator;  this is one of the reasons
+  why you should not use adaption (see \secref{sec:adaption}) frivolously.%
+\end{isamarkuptext}%
+\isamarkuptrue%
+%
+\isamarkupsubsection{Code antiquotation%
+}
+\isamarkuptrue%
+%
+\begin{isamarkuptext}%
+In scenarios involving techniques like reflection it is quite common
+  that code generated from a theory forms the basis for implementing
+  a proof procedure in \isa{SML}.  To facilitate interfacing of generated code
+  with system code, the code generator provides a \isa{code} antiquotation:%
+\end{isamarkuptext}%
+\isamarkuptrue%
+%
+\isadelimquote
+%
+\endisadelimquote
+%
+\isatagquote
+\isacommand{datatype}\isamarkupfalse%
+\ form\ {\isacharequal}\ T\ {\isacharbar}\ F\ {\isacharbar}\ And\ form\ form\ {\isacharbar}\ Or\ form\ form\isanewline
+\isanewline
+\isacommand{ML}\isamarkupfalse%
+\ {\isacharverbatimopen}\isanewline
+\ \ fun\ eval{\isacharunderscore}form\ %
+\isaantiq
+code\ T%
+\endisaantiq
+\ {\isacharequal}\ true\isanewline
+\ \ \ \ {\isacharbar}\ eval{\isacharunderscore}form\ %
+\isaantiq
+code\ F%
+\endisaantiq
+\ {\isacharequal}\ false\isanewline
+\ \ \ \ {\isacharbar}\ eval{\isacharunderscore}form\ {\isacharparenleft}%
+\isaantiq
+code\ And%
+\endisaantiq
+\ {\isacharparenleft}p{\isacharcomma}\ q{\isacharparenright}{\isacharparenright}\ {\isacharequal}\isanewline
+\ \ \ \ \ \ \ \ eval{\isacharunderscore}form\ p\ andalso\ eval{\isacharunderscore}form\ q\isanewline
+\ \ \ \ {\isacharbar}\ eval{\isacharunderscore}form\ {\isacharparenleft}%
+\isaantiq
+code\ Or%
+\endisaantiq
+\ {\isacharparenleft}p{\isacharcomma}\ q{\isacharparenright}{\isacharparenright}\ {\isacharequal}\isanewline
+\ \ \ \ \ \ \ \ eval{\isacharunderscore}form\ p\ orelse\ eval{\isacharunderscore}form\ q{\isacharsemicolon}\isanewline
+{\isacharverbatimclose}%
+\endisatagquote
+{\isafoldquote}%
+%
+\isadelimquote
+%
+\endisadelimquote
+%
+\begin{isamarkuptext}%
+\noindent \isa{code} takes as argument the name of a constant;  after the
+  whole \isa{SML} is read, the necessary code is generated transparently
+  and the corresponding constant names are inserted.  This technique also
+  allows to use pattern matching on constructors stemming from compiled
+  \isa{datatypes}.
+
+  For a less simplistic example, theory \hyperlink{theory.Ferrack}{\mbox{\isa{Ferrack}}} is
+  a good reference.%
+\end{isamarkuptext}%
+\isamarkuptrue%
+%
+\isamarkupsubsection{Imperative data structures%
+}
+\isamarkuptrue%
+%
+\begin{isamarkuptext}%
+If you consider imperative data structures as inevitable for a specific
+  application, you should consider
+  \emph{Imperative Functional Programming with Isabelle/HOL}
+  (\cite{bulwahn-et-al:2008:imperative});
+  the framework described there is available in theory \hyperlink{theory.Imperative-HOL}{\mbox{\isa{Imperative{\isacharunderscore}HOL}}}.%
+\end{isamarkuptext}%
+\isamarkuptrue%
+%
+\isadelimtheory
+%
+\endisadelimtheory
+%
+\isatagtheory
+\isacommand{end}\isamarkupfalse%
+%
+\endisatagtheory
+{\isafoldtheory}%
+%
+\isadelimtheory
+%
+\endisadelimtheory
+\isanewline
+\end{isabellebody}%
+%%% Local Variables:
+%%% mode: latex
+%%% TeX-master: "root"
+%%% End:




