Add Path#len and make #pairs more flexible

pangloss · Oct 23, 2012 · 234f55e · 234f55e
1 parent 5d8876a
commit 234f55e
Showing 1 changed file with 9 additions and 3 deletions.
diff --git a/lib/pacer/core/graph/path_route.rb b/lib/pacer/core/graph/path_route.rb
@@ -59,9 +59,15 @@ def tails(et = :vertex)
       end
     end
 
-    def pairs
-      map element_type: :path, route_name: 'pairs' do |path|
-        [path.first, path.last]
+    def pairs(head = 0, tail = -1)
+      map element_type: :path, route_name: "pairs[#{ head },#{ tail }]" do |path|
+        [path[head], path[tail]]
+      end
+    end
+
+    def len(n)
+      select do |path|
+        n === path.length
       end
     end