/// <summary>
/// Print the state machine as DOT notation suitable for drawing graphs.
/// This is a useful debug functionality!!
/// </summary>
/// <param name="automata">Automata to generate graph for</param>
/// <param name="input">Input to highlight the current state with</param>
/// <param name="graphName">Graph name as specified in notation</param>
/// <returns></returns>
internal static string AsDotNotation <TState>(this FiniteAutomata <TState> automata, string input, string graphName = "automata") where TState : FiniteAutomata <TState> .BaseState
{
// Draw the *FA as a directed graph with the state numbers in circles
// Use a double circle for accepting states
//
// digraph graphname {
// digraph G {
// [node shape="circle"]
// 1 [shape="doublecircle"]
// 1 -> 2 [label=a]
//}
StringBuilder sb = new StringBuilder();
sb.Append("digraph " + graphName + " {\n");
sb.Append("\t[node shape=\"circle\"]\n");
sb.Append("\tgraph [rankdir=\"LR\"]\n");
IEnumerable <TState> currentStates = Enumerable.Empty <TState>();
bool matchSuccessful = false;
if (!string.IsNullOrEmpty(input))
{
StimulateResult <TState> stimulateResult = automata.Stimulate(input);
matchSuccessful = (input == stimulateResult.Matched);
sb.AppendFormat("\tlabel=\"Matched: {0}\"\n", stimulateResult.Matched.Replace("\"", "\\\""));
sb.Append("\tlabelloc=top;\n");
sb.Append("\tlabeljust=center;\n");
currentStates = stimulateResult.ActiveStates;
}
foreach (Transition <TState> transition in automata.Transitions)
{
sb.Append(string.Format("\t{0} -> {1} [label=\"{2}\"]\n",
transition.From.StateNumber,
transition.To.StateNumber,
transition.TransitionLabel().Replace("\\", "\\\\").Replace("\"", "\\\"")));
}
foreach (TState state in automata.States.Where(f => f.AcceptState || currentStates.Contains(f)))
{
sb.AppendFormat("\t{0} [{1}{2}]\n",
state.StateNumber,
state.AcceptState ? "shape=\"doublecircle\"" : "",
currentStates.Contains(state) ?
string.Format(" fillcolor=\"{0}\" style=\"filled\"", matchSuccessful ? "green" : "red")
: "");
}
sb.Append("}");
return(sb.ToString());
}