feat(router): add support for custom url matchers

Closes #12442
Closes #12772

modules/@angular/router/src/shared.ts

@@ -6,6 +6,11 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
+
+import {Route, UrlMatchResult} from './config';
+import {UrlSegment, UrlSegmentGroup} from './url_tree';
+
+
 /**
  * @whatItDoes Name of the primary outlet.
  *
@@ -30,3 +35,35 @@ export class NavigationCancelingError extends Error {
   }
   toString(): string { return this.message; }
 }
+
+export function defaultUrlMatcher(
+    segments: UrlSegment[], segmentGroup: UrlSegmentGroup, route: Route): UrlMatchResult {
+  const path = route.path;
+  const parts = path.split('/');
+  const posParams: {[key: string]: UrlSegment} = {};
+  const consumed: UrlSegment[] = [];
+
+  let currentIndex = 0;
+
+  for (let i = 0; i < parts.length; ++i) {
+    if (currentIndex >= segments.length) return null;
+    const current = segments[currentIndex];
+
+    const p = parts[i];
+    const isPosParam = p.startsWith(':');
+
+    if (!isPosParam && p !== current.path) return null;
+    if (isPosParam) {
+      posParams[p.substring(1)] = current;
+    }
+    consumed.push(current);
+    currentIndex++;
+  }
+
+  if (route.pathMatch === 'full' &&
+      (segmentGroup.hasChildren() || currentIndex < segments.length)) {
+    return null;
+  } else {
+    return {consumed, posParams};
+  }
+}