src/Pure/General/graph_display.ML

prefer old graph browser in Isabelle/jEdit, which still produces better layout;
clarified print mode "active_graph": allow to switch "browser" vs. "graphview" uniformly;
tuned signature;

(*  Title:      Pure/General/graph_display.ML
    Author:     Makarius

Generic graph display, with browser and graphview backends.
*)

signature GRAPH_DISPLAY =
sig
  type node =
   {name: string, ID: string, dir: string, unfold: bool,
    path: string, parents: string list, content: Pretty.T list}
  type graph = node list
  val write_graph_browser: Path.T -> graph -> unit
  val browserN: string
  val graphviewN: string
  val active_graphN: string
  val display_graph: graph -> unit
end;

structure Graph_Display: GRAPH_DISPLAY =
struct

(* external graph representation *)

type node =
 {name: string, ID: string, dir: string, unfold: bool,
  path: string, parents: string list, content: Pretty.T list};

type graph = node list;


(* print modes *)

val browserN = "browser";
val graphviewN = "graphview";
val active_graphN = "active_graph";

fun is_browser () =
  (case find_first (fn m => m = browserN orelse m = graphviewN) (print_mode_value ()) of
    SOME m => m = browserN
  | NONE => true);


(* encode graph *)

fun encode_browser (graph: graph) =
  cat_lines (map (fn {name, ID, dir, unfold, path, parents, ...} =>
    "\"" ^ name ^ "\" \"" ^ ID ^ "\" \"" ^ dir ^ (if unfold then "\" + \"" else "\" \"") ^
    path ^ "\" > " ^ space_implode " " (map quote parents) ^ " ;") graph);

fun write_graph_browser path graph = File.write path (encode_browser graph);


val encode_content = YXML.parse_body o Pretty.symbolic_string_of o Pretty.chunks;

fun encode_graphview (graph: graph) =
  Graph.empty
  |> fold (fn {ID, name, content, ...} => Graph.new_node (ID, (name, content))) graph
  |> fold (fn {ID = a, parents = bs, ...} => fold (fn b => Graph.add_edge (b, a)) bs) graph
  |> let open XML.Encode in Graph.encode string (pair string encode_content) end;

fun write_graph_graphview path graph =
  File.write path (YXML.string_of_body (encode_graphview graph));


(* display graph *)

fun display_graph graph =
  if print_mode_active active_graphN then
    let
      val (markup, body) =
        if is_browser () then (Markup.browserN, encode_browser graph)
        else (Markup.graphviewN, YXML.string_of_body (encode_graphview graph));
      val ((bg1, bg2), en) =
        YXML.output_markup_elem (Active.make_markup markup {implicit = false, properties = []});
    in writeln ("See " ^ bg1 ^ body ^ bg2 ^ "graph" ^ en) end
  else
    let
      val (write, tool) =
        if is_browser () then (write_graph_browser, "browser")
        else (write_graph_graphview, "graphview");

      val _ = writeln "Displaying graph ...";
      val path = Isabelle_System.create_tmp_path "graph" "";
      val _ = write path graph;
      val _ = Isabelle_System.isabelle_tool tool ("-c " ^ File.shell_path path ^ " &");
    in () end;

end;