Support optional named route parameters.

src/main/scala/com/thinkminimo/step/StepKernel.scala

@@ -51,10 +51,16 @@ trait StepKernel
   protected implicit def string2RouteMatcher(path: String): RouteMatcher = {
     val pattern = """:\w+"""
     val names = new Regex(pattern) findAllIn path toList
-    val re = new Regex("^%s$" format path.replaceAll(pattern, "(.+?)"))
+    val re = new Regex("^%s$" format path.replaceAll(pattern, "([^/?]+)"))
     // By overriding toString, we can list the available routes in the default notFound handler.
     new RouteMatcher {
-      def apply() = re findFirstMatchIn requestPath map (x => Map(names zip (x.subgroups map { Seq(_) })  : _*))
+      def apply() = (re findFirstMatchIn requestPath)
+        .map { reMatch => names zip reMatch.subgroups }
+        .map { pairs =>
+          // filter out nulls (i.e., unset optional parameters) and build a multimap
+          Map(pairs flatMap { case (k, v) => if (v != null) Some(k, Seq(v)) else None } : _*)
+        }
+
       override def toString = path
     }
   }

src/test/scala/com/thinkminimo/step/RouteTest.scala

@@ -1,3 +1,6 @@
+/* 
+ * Most of these test cases are ported from http://github.com/sinatra/sinatra/tree master/test/routing_test.rb
+ */
 package com.thinkminimo.step
 
 import org.scalatest.matchers.ShouldMatchers
@@ -6,6 +9,10 @@ class RouteTestServlet extends Step {
   get(params.getOrElse("booleanTest", "false") == "true") {
     "matched boolean route"    
   }
+
+  get("/optional/?:foo?/?:bar?") {
+    (for (key <- List(":foo", ":bar") if params.isDefinedAt(key)) yield key+"="+params(key)).mkString(";")
+  }
 }
 
 class RouteTest extends StepSuite with ShouldMatchers {
@@ -16,4 +23,18 @@ class RouteTest extends StepSuite with ShouldMatchers {
       body should equal ("matched boolean route")
     }
   }
+
+  test("supports optional named params") {
+    get("/optional/hello/world") {
+      body should equal (":foo=hello;:bar=world")
+    }
+
+    get("/optional/hello") {
+      body should equal (":foo=hello")
+    }
+
+    get("/optional") {
+      body should equal ("")
+    }
+  }
 }