# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1412445917 -7200
# Node ID 953c5b53d8accca1d2d517a2e8c77843a86e989e
# Parent  ea1c7b3a92cc466fac0852f9a2072fd230204f60
Propagate context information through selectors for pattern iterators; prevent
the introduction of enumerations from datetime information that will
unnecessarily constrain patterns.

diff -r ea1c7b3a92cc -r 953c5b53d8ac vRecurrence.py
--- a/vRecurrence.py	Sat Oct 04 19:52:31 2014 +0200
+++ b/vRecurrence.py	Sat Oct 04 20:05:17 2014 +0200
@@ -167,10 +167,7 @@
         # Datetime value at wider resolution.
 
         if _pos < pos:
-            if have_q:
-                l.append(from_dt)
-            else:
-                context.append(from_dt.args["values"][0])
+            context.append(from_dt.args["values"][0])
             from_dt = get_next(iter_dt)
 
         # Qualifier at wider or same resolution as datetime value.
@@ -178,8 +175,8 @@
         else:
             if not have_q:
                 if isinstance(from_q, Enum) and pos > 0:
-                    repeat = Pattern(pos - 1, {"interval" : 1, "values" : [context[-1]]}, "REPEAT")
-                    repeat.context = tuple(context[:-1])
+                    repeat = Pattern(pos - 1, {"interval" : 1}, "REPEAT")
+                    repeat.context = tuple(context)
                     l.append(repeat)
                 else:
                     from_q.context = tuple(context)
@@ -193,7 +190,8 @@
             # Or combine the qualifier and value details.
 
             else:
-                l.append(combine_value_with_qualifier(from_dt, from_q))
+                context.append(from_dt.args["values"][0])
+                l.append(combine_context_with_qualifier(context, from_q))
                 from_dt = get_next(iter_dt)
 
             from_q = get_next(iter_q)
@@ -207,8 +205,8 @@
     while from_q:
         if not have_q:
             if isinstance(from_q, Enum) and pos > 0:
-                repeat = Pattern(pos - 1, {"interval" : 1, "values" : [context[-1]]}, "REPEAT")
-                repeat.context = tuple(context[:-1])
+                repeat = Pattern(pos - 1, {"interval" : 1}, "REPEAT")
+                repeat.context = tuple(context)
                 l.append(repeat)
             else:
                 from_q.context = tuple(context)
@@ -218,15 +216,15 @@
 
     return l
 
-def combine_value_with_qualifier(from_dt, from_q):
+def combine_context_with_qualifier(context, from_q):
 
     """
-    Combine value information supplied by 'from_dt' (a datetime) and 'from_q'
-    (a qualifier), imposing the datetime value information on any qualifiers.
+    Combine 'context' information (a datetime) and 'from_q' (a qualifier),
+    imposing the datetime value information on any qualifiers.
     """
 
-    if not from_q.args.has_key("values") and from_dt.args.has_key("values"):
-        from_q.args["values"] = from_dt.args["values"]
+    if not from_q.args.has_key("values"):
+        from_q.context = tuple(context)
     return from_q
 
 # Datetime arithmetic.
@@ -309,7 +307,7 @@
 
 class Pattern(Selector):
     def materialise_items(self, context, start, end, counter):
-        first = scale(self.args["values"][0], self.pos)
+        first = scale(self.context[self.pos], self.pos)
 
         # Define the step between items.