updated docstring of get_reader_from_filename

src/pypore/io/__init__.py

@@ -1,5 +1,23 @@
-
+# TODO implement tests for this!
 def get_reader_from_filename(filename):
+    """
+    Returns an instance of an implementation of :py:class:`pypore.io.abstract_reader.AbstractReader` based on the
+    extension of filename.
+
+    :param string filename: Filename to get the reader for.
+    :returns: An open reader of an implementation of :py:class:`pypore.io.abstract_reader.AbstractReader` based on the\
+             extension of filename, for the following extensions.
+
+        - '.h5' extension: returns an instance of :py:class:`pypore.io.data_file_reader.DataFileReader`.
+        - '.log' extension: returns :py:class:`pypore.io.chimera_reader.ChimeraReader`.
+
+        If the file extension is not in the above list, None is returned.
+
+    :raise: Exception - this method opens a reader, which could throw an exception.
+
+    >>> reader = get_reader_from_filename('test.h5') # Returns an open DataFileReader
+    >>> data = reader.get_all_data()
+    """
 
     # TODO implement for other file types
 
@@ -10,17 +28,11 @@ def get_reader_from_filename(filename):
     elif '.log' in filename:
         from chimera_reader import ChimeraReader as ReaderClass
     else:
-        print "error"
-        return "No default reader available for file extension of {0}".format(filename)
-
-    try:
-        reader = ReaderClass(filename)
-        return reader
-    except Exception, e:
-        print e
-        return e.message
-
+        raise ValueError(
+            "No default match for the extension of {0}. Default extensions include '.h5', '.log'.".format(filename))
 
+    reader = ReaderClass(filename)
+    return reader
 
     # elif '.hkd' in filename:
     #     return open_heka_file(filename, decimate)