The selection view now works. Functions can return a dataset.Selection object which will be stored in the selection list.

system/dataset.py

@@ -271,7 +271,7 @@ class GraphDataset(Dataset):
         return G
 
 Dataset._all_dims=set()
-        
+
 class ReverseDict(dict):
     """
     A dictionary which can lookup values by key, and keys by value.
@@ -319,7 +319,25 @@ def from_file(filepath):
             
     return out_data
     
-class Selection:
+class Selection(dict):
     """Handles selected identifiers along each dimension of a dataset"""
-    def __init__(self):
-        self.current_selection={}
+
+    def __init__(self, title='Unnamed Selecton'):
+        self.title = title
+        
+    def __getitem__(self, key):
+        if not self.has_key(key):
+            return None
+        return dict.__getitem__(self, key)
+
+    def dims(self):
+        return self.keys()
+        
+    def axis_len(self, axis):
+        if self._selection.has_key(axis):
+            return len(self._selection[axis])
+        return 0
+
+    def select(self, axis, labels):
+        self[axis] = labels
+