implement some new propagation strategies

build.sbt

@@ -1,7 +1,7 @@
 lazy val commonSettings = Seq(
   name                  := "ostrich",
   organization          := "uuverifiers",
-  version               := "1.3.5",
+  version               := "1.4pre",
 //
   homepage              := Some(url("https://github.com/uuverifiers/ostrich")),
   licenses              := Seq("BSD-3-Clause" -> url("https://opensource.org/licenses/BSD-3-Clause")),
@@ -49,9 +49,9 @@ lazy val commonSettings = Seq(
                              )
                           ),
 //
-  scalaVersion          := "2.11.12",
-  crossScalaVersions    := Seq("2.11.12", "2.12.17"),
+  scalaVersion          := "2.13.14",
   scalacOptions         += "-deprecation",
+  scalacOptions         += "-Wunused",
   fork in run           := true,
   cancelable in Global  := true,
 //

ostrich

@@ -21,7 +21,7 @@ ostrichParams=""
 
 for p; do
     case "$p" in
-        [+-]eager | [+-]forward | -length=* | [+-]minimizeAutomata | [+-]parikh | -regexTranslator=*)
+        [+-]eager | [+-]forward | -length=* | [+-]minimizeAutomata | [+-]parikh  | -regexTranslator=* | [+-]backwardOnly | [+-]forwardOnly | [+-]forwardBackward)
             if [ x"$ostrichParams" = x"" ]; then
                 ostrichParams=$p
             else

src/main/scala/ostrich/ECMARegexParser.scala

@@ -39,12 +39,18 @@ import ecma2020regex._
 import ecma2020regex.Absyn._
 import ecma2020regex.Absyn.{Quantifier => ECMAQuantifier}
 
-import scala.collection.JavaConversions.{asScalaBuffer, asScalaIterator}
+import scala.collection.JavaConverters.asScala
 
 object ECMARegexParser {
 
   val OctalEscape = """[0-7]{1,3}""".r
 
+  implicit def impToScalaList[A](l : java.util.List[A]) : Seq[A] =
+    asScala(l).toSeq
+
+  implicit def impToScalaIterator[A](l : java.util.Iterator[A]) : Iterator[A] =
+    asScala(l)
+
   val UnsupportedFlag = """[^ius]""".r
 
 }