[svn] r6302: nemerle/trunk/lib/rlist.n

[d]

Log:
Add Last, @+ and Item.

Author: d
Date: Wed May 17 22:49:29 2006
New Revision: 6302

Modified:
   nemerle/trunk/lib/rlist.n

Modified: nemerle/trunk/lib/rlist.n
==============================================================================
--- nemerle/trunk/lib/rlist.n	(original)
+++ nemerle/trunk/lib/rlist.n	Wed May 17 22:49:29 2006
@@ -301,6 +301,32 @@
       Tail (this)
     }
 
+    /** Returns the last element of the RList [xs].
+        Time complexity: O (log (|xs|)).
+        <param name="xs">
+          The RList, which last element is going to be returned. 
+        </param>
+        <returns> 
+          The last element of [xs].
+        </returns>
+     */
+    public static Last (xs : RList ['a]) : 'a {
+      | Zero (ps) => RList [Pair ['a]].Last (ps).snd; 
+      | One (x, Nil) => x
+      | One (_, ps) => RList [Pair ['a]].Last (ps).snd;
+      | Nil => throw System.ArgumentException ("RList.Last called for empty RList")
+    }
+
+    /** Returns the last element of the RList [this].
+        Time complexity: O (log (|this|)).
+        <returns> 
+          The last element of [this].
+        </returns>
+     */
+    public Last () : 'a {
+      Last (this)
+    }
+
     /* An auxillary function used by the Length property. 
        Time complexity: O (log (|xs|)).
      */
@@ -562,6 +588,24 @@
       Append (this, ys)
     }   
 
+    /** Returns an a new RList composed by appending [ys]
+        at the end of [xs].
+        Time complexity: roughly O (|xs| * log (|ys| + |xs|)).
+        An alias for Append.
+        <param name="xs">
+          The RList, which elements come first in the resulting RList.
+        </param>
+        <param name="ys">
+          The RList, which elements come second in the resulting RList.
+        </param>
+        <returns>
+          An RList composed by appending [ys] at the end of [xs]. 
+        </returns>
+     */
+    public static @+ (xs : RList ['a], ys : RList ['a]) : RList ['a] {
+      Append (xs, ys)
+    }   
+
     /** Returns an RList composed of the elements of list [xs].
         Use RList (xs, |xs|) if |xs| is known.
         Time complexity: O (|xs|).
@@ -679,6 +723,10 @@
         | Nil => {}
       }
     }
+
+    public Item [index : int] : 'a {
+      get { Nth (this, index) } 
+    }
   }
 }