revset: added operations to duck type baseset

Added more operations which are not lazy but only used so far to duck type
baseset.

Their implementations will be changed in future patches.

mercurial/revset.py

@@ -2100,5 +2100,26 b' class lazyset(object):'
         l = baseset([r for r in self])
         return l + baseset(x)
 
+    def __len__(self):
+        # Basic implementation to be changed in future patches.
+        l = baseset([r for r in self])
+        return len(l)
+
+    def __getitem__(self, x):
+        # Basic implementation to be changed in future patches.
+        l = baseset([r for r in self])
+        return l[x]
+
+    def sort(self, reverse=False):
+        # Basic implementation to be changed in future patches.
+        self._subset = baseset(self._subset)
+        self._subset.sort(reverse=reverse)
+
+    def reverse(self):
+        self._subset.reverse()
+
+    def set(self):
+        return set([r for r in self])
+
 # tell hggettext to extract docstrings from these functions:
 i18nfunctions = symbols.values()