diff --git a/python/web/library/fileformat.py b/python/web/library/fileformat.py
index 400e227..b189217 100644
--- a/python/web/library/fileformat.py
+++ b/python/web/library/fileformat.py
@@ -9,7 +9,7 @@ fields = {
     'book':
         [('isbn', 's'), ('title', 's'), ('category', 's'),
          ('subtitle', 's'), ('persons', 'd'), ('publisher', 's'),
-         ('published_year', 's'), ('edition', 's'), ('num_pages', 's'),
+         ('published_year', 'i'), ('edition', 'i'), ('num_pages', 'i'),
          ('series', 's'), ('description', 's'), # TODO picture, thumbnail
          ('references', 'd')],
     'person':
@@ -57,6 +57,11 @@ class CommitFormatSyntaxError(Exception):
 def read_field_value_str(val):
     return '\n'.join(map(lambda x: x.strip(), val.split('\n'))).strip()
 
+def read_field_value_int(val):
+    if val.strip() == '':
+        return None
+    return int(val.strip())
+
 def read_field_value_dict(val):
     d = {}
     for line in val.strip().split('\n'):
@@ -71,7 +76,13 @@ def read_field_value_list(val):
     return val.strip().split(' ')
 
 def read_action(text):
+    '''
+    Parse text as an action, returning a dictionary.
+    '''
     lines = text.split('\n')
+    print 'reading action'
+    print 'lines:'
+    print lines
     d = {}
     lastfield = None
     for line in lines:
@@ -85,9 +96,14 @@ def read_action(text):
             field, value = line.split(':', 1)
             d[field] = value.strip()
             lastfield = field
+
     if 'action' not in d:
         raise CommitFormatSyntaxError('Missing \'action\' field')
     action = d['action']
+
+    print 'dict:'
+    print d
+
     for field in action_fields[action]['required']:
         if field not in d:
             raise CommitFormatSyntaxError('Missing required field \'%s\' in \'%s\' action' % (field, action))
@@ -96,12 +112,18 @@ def read_action(text):
     for field, ftype in fields[data_type]:
         if field in d:
             reader = { 's': read_field_value_str,
+                       'i': read_field_value_int,
                        'd': read_field_value_dict,
                        'l': read_field_value_list }[ftype]
             result[field] = reader(d[field])
     return result
 
 def read_actionlist(text):
+    '''
+    Parse text as a list of actions.
+
+    The result is a list of dictionaries.
+    '''
     return map(lambda x: read_action(x.strip()),
                text.split('\n\n'))
 
@@ -144,6 +166,7 @@ def write_action(d):
     for field, ftype in fields[data_type]:
         if field in d:
             value_writer = {'s': write_field_value_str,
+                            'i': write_field_value_str,
                             'd': write_field_value_dict,
                             'l': write_field_value_list}[ftype]
             lines += field + ':' + value_writer(d[field])