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theory Antiquotes+
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imports "../Appendix"+
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begin+
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+
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section \<open>Useful Document Antiquotations\label{rec:docantiquotations}\<close>+
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+
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text \<open>+
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  {\bf Problem:} +
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  How to keep your ML-code inside a document synchronised with the actual code?\smallskip+
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+
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  {\bf Solution:} This can be achieved with document antiquotations.\smallskip+
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+
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  Document antiquotations can be used for ensuring consistent type-setting of+
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  various entities in a document. They can also be used for sophisticated+
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  \LaTeX-hacking. If you type on the Isabelle level+
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\<close>+
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+
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print_antiquotations+
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+
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text \<open>+
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  you obtain a list of all currently available document antiquotations and+
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  their options.  +
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+
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  Below we will give the code for two additional document+
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  antiquotations both of which are intended to typeset ML-code. The crucial point+
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  of these document antiquotations is that they not just print the ML-code, but also +
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  check whether it compiles. This will provide a sanity check for the code+
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  and also allows you to keep documents in sync with other code, for example+
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  Isabelle.+
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+
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  We first describe the antiquotation \<open>ML_checked\<close> with the syntax:+
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 +
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  @{text [display] \<open>@{ML_checked "a_piece_of_code"}\<close>}+
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+
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  The code is checked by sending the ML-expression @{text [quotes] "val _ =+
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  a_piece_of_code"} to the ML-compiler (i.e.~the function @{ML \<open>ML_Context.eval_source_in\<close>} in Line 7 below). The complete code of the+
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  document antiquotation is as follows:+
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+
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\<close>+
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ML \<open>Input.pos_of\<close>+
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ML%linenosgray\<open>fun ml_enclose bg en source =+
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  ML_Lex.read bg @ ML_Lex.read_source false source @ ML_Lex.read en;\<close>+
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+
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ML%linenosgray\<open>fun ml_val code_txt = (ml_enclose "val _ = " "" code_txt)+
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+
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fun output_ml ctxt code_txt =+
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let+
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  val _ = ML_Context.eval_in (SOME ctxt) ML_Compiler.flags (Input.pos_of code_txt) (ml_val code_txt)+
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in +
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   Pretty.str (Input.source_content code_txt)+
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end+
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+
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val ml_checked_setup = Thy_Output.antiquotation_pretty_source @{binding "ML_checked"} (Scan.lift Args.text_input) output_ml\<close>+
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+
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setup \<open>ml_checked_setup\<close>+
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+
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+
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text \<open>+
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  The parser @{ML \<open>(Scan.lift Args.name)\<close>} in Line 7 parses a string, in this+
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  case the code, and then calls the function @{ML output_ml}. As mentioned+
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  before, the parsed code is sent to the ML-compiler in Line 4 using the+
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  function @{ML ml_val}, which constructs the appropriate ML-expression, and+
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  using @{ML \<open>eval_in\<close> in ML_Context}, which calls the compiler.  If the code is+
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  ``approved'' by the compiler, then the output function @{ML \<open>output\<close> in+
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  Document_Antiquotation} in the next line pretty prints the code. This function expects+
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  that the code is a list of (pretty)strings where each string correspond to a+
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  line in the output. Therefore the use of @{ML \<open>(space_explode "\\n" txt)\<close>+
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  for txt} which produces such a list according to linebreaks.  There are a+
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  number of options for antiquotations that are observed by the function +
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  @{ML \<open>output\<close> in Document_Antiquotation} when printing the code (including \<open>[display]\<close> +
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  and \<open>[quotes]\<close>). The function @{ML \<open>antiquotation_raw\<close> in Thy_Output} in +
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  Line 7 sets up the new document antiquotation.+
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+
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  \begin{readmore}+
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  For more information about options of document antiquotations see \rsccite{sec:antiq}).+
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  \end{readmore}+
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+
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  Since we used the argument @{ML \<open>Position.none\<close>}, the compiler cannot give specific +
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  information about the line number, in case an error is detected. We +
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  can improve the code above slightly by writing +
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\<close>+
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(* FIXME: remove+
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ML%linenosgray{*fun output_ml ctxt (code_txt, pos) =+
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let+
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  val srcpos = {delimited = false, pos = pos, text = ml_val code_txt}+
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in+
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  (ML_Context.eval_source_in (SOME ctxt) ML_Compiler.flags srcpos;+
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   code_txt +
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   |> space_explode "\n"+
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   |> map Pretty.str+
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   |> Pretty.list "" ""+
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   |> Document_Antiquotation.output ctxt+
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   |> Latex.string)+
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end+
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+
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val ml_checked_setup2 = Thy_Output.antiquotation @{binding "ML_checked2"}+
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         (Scan.lift (Parse.position Args.name)) output_ml *}+
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+
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setup {* ml_checked_setup2 *}+
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*)+
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text \<open>+
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  where in Lines 1 and 2 the positional information is properly treated. The+
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  parser @{ML Parse.position} encodes the positional information in the +
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  result.+
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+
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  We can now write \<open>@{ML_checked2 "2 + 3"}\<close> in a document in order to+
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  obtain @{ML_checked "2 + 3"} and be sure that this code compiles until+
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  somebody changes the definition of addition.+
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+
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+
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  The second document antiquotation we describe extends the first by a pattern+
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  that specifies what the result of the ML-code should be and checks the+
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  consistency of the actual result with the given pattern. For this we are+
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  going to implement the document antiquotation:+
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+
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  +
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  @{text [display] \<open>@{ML_resp "a_piece_of_code" "a_pattern"}\<close>}+
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  +
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  To add some convenience and also to deal with large outputs, the user can+
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  give a partial specification by using ellipses. For example \<open>(\<dots>, \<dots>)\<close>+
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  for specifying a pair.  In order to check consistency between the pattern+
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  and the output of the code, we have to change the ML-expression that is sent +
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  to the compiler: in \<open>ML_checked2\<close> we sent the expression @{text [quotes]+
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  "val _ = a_piece_of_code"} to the compiler; now the wildcard \<open>_\<close>+
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  must be be replaced by the given pattern. However, we have to remove all+
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  ellipses from it and replace them by @{text [quotes] "_"}. The following +
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  function will do this:+
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\<close>+
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+
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ML%linenosgray\<open>fun ml_pat pat code =+
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  ML_Lex.read "val" @ ML_Lex.read_source false pat @ ML_Lex.read " = " @ ML_Lex.read_source false code\<close>+
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+
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(*+
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ML %grayML{*fun ml_pat code_txt pat =+
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let val pat' = +
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         implode (map (fn "\<dots>" => "_" | s => s) (Symbol.explode pat))+
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in +
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  ml_enclose ("val " ^ pat' ^ " = ") "" code_txt +
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end*}+
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*)+
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text \<open>+
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  Next we add a response indicator to the result using:+
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\<close>+
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+
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+
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ML %grayML\<open>fun add_resp pat = map (fn s => "> " ^ s) pat\<close>+
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+
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text \<open>+
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  The rest of the code of \<open>ML_resp\<close> is: +
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\<close>+
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+
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ML %linenosgray\<open>+
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fun output_ml_resp ctxt (code_txt, pat) =+
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let+
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  val _ = ML_Context.eval_in (SOME ctxt) ML_Compiler.flags (Input.pos_of code_txt) (ml_pat pat code_txt)+
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  val code = space_explode "\n" (Input.source_content code_txt)+
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  val resp = add_resp (space_explode "\n" (Input.source_content pat))+
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in +
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   Pretty.str (cat_lines (code @ resp))+
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end+
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+
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val ml_response_setup = Thy_Output.antiquotation_pretty_source @{binding "ML_resp"} (Scan.lift (Args.text_input -- Args.text_input)) output_ml_resp+
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+
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\<close>+
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+
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(*+
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ML %linenosgray{*fun output_ml_resp {context = ctxt, ...} ((code_txt, pat), pos) = +
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  (let+
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     val srcpos = {delimited = false, text = ml_pat (code_txt, pat), pos = pos}+
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   in+
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     ML_Context.eval_source_in (SOME ctxt) ML_Compiler.flags srcpos +
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   end;+
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   let +
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     val code_output = space_explode "\n" code_txt +
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     val resp_output = add_resp (space_explode "\n" pat)+
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   in +
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     Thy_Output.output ctxt (map Pretty.str (code_output @ resp_output)) +
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   end)+
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+
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+
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val ml_resp_setup = Thy_Output.antiquotation @{binding "ML_resp"} +
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          (Scan.lift (Parse.position (Args.text_input -- Args.text_input))) +
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             output_ml_resp*}+
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*)+
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setup \<open>ml_response_setup\<close>+
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+
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(* FIXME *)+
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text \<open>+
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  In comparison with \<open>ML_checked\<close>, we only changed the line about +
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  the compiler (Line~2), the lines about+
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  the output (Lines 4 to 7) and the parser in the setup (Line 11). Now +
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  you can write+
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 +
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  @{text [display] \<open>@{ML_resp [display] "true andalso false" "false"}\<close>}+
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+
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  to obtain+
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+
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  @{ML_resp [display] "true andalso false" "false"} +
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+
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  or +
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+
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  @{text [display] \<open>@{ML_resp [display] "let val i = 3 in (i * i, "foo") end" "(9, \<dots>)"}\<close>}+
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  +
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  to obtain+
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+
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  @{ML_resp [display] "let val i = 3 in (i * i, \"foo\") end" "(9, _)"} +
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+
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  In both cases, the check by the compiler ensures that code and result+
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  match. A limitation of this document antiquotation, however, is that the+
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  pattern can only be given for values that can be constructed. This excludes+
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  values that are abstract datatypes, like @{ML_type thm}s and @{ML_type cterm}s.+
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+
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\<close>+
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end+
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