# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1508534396 -7200
# Node ID 6975cdaac4a4c54debc18038ea94d3781f5330b5
# Parent  102a5f873a8b3c53faf2796770ec886c5b4ee730
Simplify the interface of the rule periods computation function.

diff -r 102a5f873a8b -r 6975cdaac4a4 imiptools/data.py
--- a/imiptools/data.py	Fri Oct 20 22:52:13 2017 +0200
+++ b/imiptools/data.py	Fri Oct 20 23:19:56 2017 +0200
@@ -1107,11 +1107,11 @@
 
     return RecurringPeriod(start, end, tzid, "RRULE", attr)
 
-def get_rule_periods(rrule, start, duration, attr, tzid, end, inclusive=False):
+def get_rule_periods(rrule, main_period, tzid, end, inclusive=False):
 
     """
-    Return periods for the given 'rrule', employing the 'start', 'duration',
-    datetime 'attr' and 'tzid'.
+    Return periods for the given 'rrule', employing the 'main_period' and
+    'tzid'.
 
     The specified 'end' datetime indicates the end of the window for which
     periods shall be computed.
@@ -1120,6 +1120,10 @@
     will be included.
     """
 
+    start = main_period.get_start()
+    attr = main_period.get_start_attr()
+    duration = main_period.get_duration()
+
     parameters = rrule and get_parameters(rrule)
     selector = get_rule(start, rrule)
 
@@ -1167,9 +1171,6 @@
 
     main_period = obj.get_main_period(tzid)
 
-    dtstart = main_period.get_start()
-    dtstart_attr = main_period.get_start_attr()
-
     # Attempt to get time zone details from the object, using the supplied zone
     # only as a fallback.
 
@@ -1191,9 +1192,8 @@
         selection_period = Period(start, None)
         periods = []
 
-        for period in get_rule_periods(rrule, dtstart,
-            main_period.get_duration(), dtstart_attr, obj_tzid or tzid, end,
-            inclusive):
+        for period in get_rule_periods(rrule, main_period, obj_tzid or tzid,
+                                       end, inclusive):
 
             # Filter out periods before the start.