add function to quad tree to turn items into strings (for later saving to file)

fcore/parser/space-dfa.sml

@@ -0,0 +1,34 @@
+structure SpaceDfa =
+struct
+  val dead = 0
+  val start = 1
+  val final = 2
+
+  fun makeDead _ = 0
+
+  fun makeStart i =
+    let
+      val chr = Char.chr i
+    in
+      if Char.isSpace chr
+      then final
+      else dead
+    end
+
+  val deadTable = Vector.tabulate (255, makeDead)
+  val startTable = Vector.tabulate (255, makeStart)
+  val finalTable = startTable
+
+  val tables = #[deadTable, startTable, finalTable]
+
+  fun isFinal state = 
+    state = final
+
+  fun next (state, chr) =
+    let
+      val table = Vector.sub (tables, state)
+      val idx = Char.ord chr
+    in
+      Vector.sub (table, idx)
+    end
+end