structure OutputTutorial =
struct

(* rebuilding the output function from ThyOutput in order to *)
(* enable the options [gray, linenos, index]                   *)

val gray = ref false
val linenos = ref false

fun output txt =
let
  val prts = map Pretty.str txt
in   
  prts
  |> (if ! ThyOutput.quotes then map Pretty.quote else I)
  |> (if ! ThyOutput.display then
    map (Output.output o Pretty.string_of o Pretty.indent (! ThyOutput.indent))
    #> space_implode "\\isasep\\isanewline%\n"
    #> (if ! linenos then (enclose "\\begin{linenos}%\n" "%\n\\end{linenos}") else I) 
    #> (if ! gray then (enclose "\\begin{graybox}%\n" "%\n\\end{graybox}") else I) 
    #> enclose "\\begin{isabelle}%\n" "%\n\\end{isabelle}"
  else
    map (Output.output o (if ! ThyOutput.break then Pretty.string_of else Pretty.str_of))
    #> space_implode "\\isasep\\isanewline%\n"
    #> enclose "\\isa{" "}")
end

datatype qstring =
  NoString
| Plain  of string
| Code   of string
| IStruc of string

datatype entry = 
   No_Entry
 | Default 
 | Explicit of string

val index = ref No_Entry

fun translate f = Symbol.explode #> map f #> implode;

val clean_string = translate
  (fn "_" => "\\_"
    | "#" => "\\#"
    | "<" => "\\isacharless"
    | ">" => "\\isachargreater"
    | "{" => "\\{"
    | "|" => "\\isacharbar"
    | "}" => "\\}"
    | "$" => "\\isachardollar"
    | "!" => "\\isacharbang"
    | "\<dash>" => "-"
    | c => c);

fun get_word str =
let 
  fun only_letters [] = true
    | only_letters (x::xs) = 
        if (Symbol.is_ascii_blank x) then false else only_letters xs
in
  if (only_letters (Symbol.explode str)) then (clean_string str)
  else error ("Underspecified index entry only for single words allowed! Error with " ^ quote str)
end  

fun get_qstring NoString = ""
  | get_qstring (Plain s) = get_word s
  | get_qstring (Code s) = let val w = get_word s in  (w ^ "@{\\tt\\slshape{}" ^ w ^ "}") end
  | get_qstring (IStruc s) =  "in {\\tt\\slshape{}" ^ (get_word s) ^ "}"

fun is_empty_qstr (Plain "") = true
  | is_empty_qstr (Code "") = true
  | is_empty_qstr _ = false

fun get_index_info {main = m, minor = n} = 
 (if n = NoString
  then "\\index{" ^ (get_qstring m) ^ "}"  
  else "\\indexdef{" ^ (get_qstring m) ^ "}{" ^ (get_qstring n) ^ "}")  
    
fun index_entry entry index_info  =
 case entry of
   No_Entry => I
 | Explicit s => prefix s
 | Default => prefix (get_index_info index_info)

fun output_indexed txt index_info =
 txt |> output
     |> index_entry (!index) index_info

fun boolean "" = true
  | boolean "true" = true
  | boolean "false" = false
  | boolean s = error ("Bad boolean value: " ^ quote s);

fun explicit "" = Default
  | explicit s  = Explicit s

val _ = ThyOutput.add_options
 [("gray", Library.setmp gray o boolean),
  ("linenos", Library.setmp linenos o boolean),
  ("index", Library.setmp index o explicit)]


end