Add NFA#to_s

lib/imbecile/regex/nfa.rb

@@ -27,6 +27,40 @@ module Imbecile
         @end_state = State.new
       end
 
+      def to_s
+        rv = ""
+        states = {start_state => 0}
+        to_visit = [start_state]
+        state_id = lambda do |state|
+          unless states.include?(state)
+            states[state] = states.values.max + 1
+            to_visit << state
+          end
+          states[state]
+        end
+        visit = lambda do |state|
+          accepts_s = state.accepts ? " *" : ""
+          rv += "#{state_id[state]}#{accepts_s}:\n"
+          state.transitions.each do |range, dest_state|
+            if range.nil?
+              range_s = "nil"
+            else
+              range_s = range.first.chr
+              if range.size > 1
+                range_s += "-" + range.last.chr
+              end
+            end
+            accepts_s = dest_state.accepts ? " *" : ""
+            rv += "  #{range_s} => #{state_id[dest_state]}#{accepts_s}\n"
+          end
+        end
+        while to_visit.size > 0
+          visit[to_visit[0]]
+          to_visit.slice!(0)
+        end
+        rv
+      end
+
       class << self
 
         def empty