contrib/nitcc: improve Automaton::to_dot

Signed-off-by: Alexandre Terrasa <alexandre@moz-code.org>

diff --git a/contrib/nitcc/src/autom.nit b/contrib/nitcc/src/autom.nit
index c9aa3e4..65ddf32 100644 (file)
--- a/contrib/nitcc/src/autom.nit
+++ b/contrib/nitcc/src/autom.nit
@@ -467,7 +467,9 @@ class Automaton
        end
 
        # Produce a graphviz string from the automatom
-       fun to_dot: String
+       #
+       # Set `merge_transitions = false` to generate one edge by transition (default true).
+       fun to_dot(merge_transitions: nullable Bool): Writable
        do
                var names = new HashMap[State, String]
                var ni = 0
@@ -477,22 +479,24 @@ class Automaton
                end
 
                var f = new Buffer
-                f.append("digraph g \{\n")
+               f.append("digraph g \{\n")
+               f.append("rankdir=LR;")
 
+               var state_nb = 0
                for s in states do
-                       f.append("s{names[s]}[shape=oval")
+                       f.append("s{names[s]}[shape=circle")
                        #f.write("label=\"\",")
                        if accept.has(s) then
-                               f.append(",color=blue")
+                               f.append(",shape=doublecircle")
                        end
                        if tags.has_key(s) then
                                f.append(",label=\"")
                                for token in tags[s] do
-                                       f.append("{token.name.escape_to_c}\\n")
+                                       f.append("{token.name.escape_to_dot}\\n")
                                end
                                f.append("\"")
                        else
-                               f.append(",label=\"\"")
+                               f.append(",label=\"{state_nb}\"")
                        end
                        f.append("];\n")
                        var outs = new HashMap[State, Array[nullable TSymbol]]
@@ -511,19 +515,26 @@ class Automaton
                        for s2, a in outs do
                                var labe = ""
                                for c in a do
+                                       if merge_transitions == false then labe = ""
                                        if not labe.is_empty then labe += "\n"
                                        if c == null then
-                                               labe += "''"
+                                               labe += "ε"
                                        else
                                                labe += c.to_s
                                        end
+                                       if merge_transitions == false then
+                                               f.append("s{names[s]}->s{names[s2]} [label=\"{labe.escape_to_dot}\"];\n")
+                                       end
+                               end
+                               if merge_transitions == null or merge_transitions == true then
+                                       f.append("s{names[s]}->s{names[s2]} [label=\"{labe.escape_to_c}\"];\n")
                                end
-                               f.append("s{names[s]}->s{names[s2]} [label=\"{labe.escape_to_c}\"];\n")
                        end
+                       state_nb += 1
                end
                f.append("empty->s{names[start]}; empty[label=\"\",shape=none];\n")
                f.append("\}\n")
-               return f.write_to_string
+               return f
        end
 
        # Transform a NFA to a DFA.