# HG changeset patch
# User Thierry Bertin-Mahieux <bertinmt@iro.umontreal.ca>
# Date 1213893341 14400
# Node ID d580b3a369a4ed97f74bb35e1cf9097a0f067bc9
# Parent  47538a45b878dde531c29dd53bde47963530bb9f
dataset__call__() returns a FieldsSubsetDataSet, so still a subset of fields, but not cached any more. I added the function dataset.cached_fields_subset(self,*fieldnames) that returns the old version, cached, in case someone needs it. Current behaviour passes the tests.

diff -r 47538a45b878 -r d580b3a369a4 dataset.py
--- a/dataset.py	Tue Jun 17 17:12:43 2008 -0400
+++ b/dataset.py	Thu Jun 19 12:35:41 2008 -0400
@@ -436,6 +436,16 @@
         Return a dataset that sees only the fields whose name are specified.
         """
         assert self.hasFields(*fieldnames)
+        #return self.fields(*fieldnames).examples()
+        fieldnames_list = list(fieldnames)
+        return FieldsSubsetDataSet(self,fieldnames_list)
+
+    def cached_fields_subset(self,*fieldnames) :
+        """
+        Behaviour is supposed to be the same as __call__(*fieldnames), but the dataset returned is cached.
+        @see : dataset.__call__
+        """
+        assert self.hasFields(*fieldnames)
         return self.fields(*fieldnames).examples()
 
     def fields(self,*fieldnames):