# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1512325154 -3600
# Node ID d39a2232c73745df4def2baeb675d0288f868565
# Parent  9f507afaa71b50033578813197c83f62ba5220fc
Introduce datetime information between selectors where appropriate.
Added a function for obtaining the selector chain from a single root.

diff -r 9f507afaa71b -r d39a2232c737 tests/qualifiers.py
--- a/tests/qualifiers.py	Sun Dec 03 17:13:17 2017 +0100
+++ b/tests/qualifiers.py	Sun Dec 03 19:19:14 2017 +0100
@@ -39,6 +39,8 @@
 show(csel)
 
 s = get_selector(dt, sel)
+csel = get_selectors_from_selector(s)
+show(csel)
 
 l = s.materialise(dt, (2003, 12, 24))
 print len(l) == 7, 7, len(l)
@@ -63,6 +65,8 @@
 show(csel)
 
 s = get_selector(dt, sel)
+csel = get_selectors_from_selector(s)
+show(csel)
 
 l = s.materialise(dt, (2003, 12, 24, 0, 0, 0))
 print len(l) == 34, 34, len(l)
@@ -84,6 +88,8 @@
 show(csel)
 
 s = get_selector(dt, sel)
+csel = get_selectors_from_selector(s)
+show(csel)
 
 l = s.materialise(dt, (1997, 12, 24))
 print len(l) == 10, 10, len(l)
@@ -104,6 +110,8 @@
 show(csel)
 
 s = get_selector(dt, sel)
+csel = get_selectors_from_selector(s)
+show(csel)
 
 l = s.materialise(dt, (1997, 12, 24, 0, 0, 0))
 print len(l) == 113, 113, len(l)
@@ -124,6 +132,8 @@
 show(csel)
 
 s = get_selector(dt, sel)
+csel = get_selectors_from_selector(s)
+show(csel)
 
 l = s.materialise(dt, (1997, 12, 24, 0, 0, 0))
 print len(l) == 57, 57, len(l)
@@ -144,6 +154,8 @@
 show(csel)
 
 s = get_selector(dt, sel)
+csel = get_selectors_from_selector(s)
+show(csel)
 
 l = s.materialise(dt, (1997, 12, 24, 0, 0, 0))
 print len(l) == 17, 17, len(l)
@@ -165,6 +177,8 @@
 show(csel)
 
 s = get_selector(dt, sel)
+csel = get_selectors_from_selector(s)
+show(csel)
 
 l = s.materialise(dt, (1997, 12, 24, 0, 0, 0))
 print len(l) == 5, 5, len(l)
@@ -187,6 +201,8 @@
 show(csel)
 
 s = get_selector(dt, sel)
+csel = get_selectors_from_selector(s)
+show(csel)
 
 l = s.materialise(dt, (2000, 1, 31, 14, 0, 0))
 print len(l) == 93, 93, len(l)
@@ -208,6 +224,8 @@
 show(csel)
 
 s = get_selector(dt, sel)
+csel = get_selectors_from_selector(s)
+show(csel)
 
 l = s.materialise(dt, (2000, 1, 31, 14, 0, 0))
 print len(l) == 93, 93, len(l)
@@ -229,6 +247,8 @@
 show(csel)
 
 s = get_selector(dt, sel)
+csel = get_selectors_from_selector(s)
+show(csel)
 
 l = s.materialise(dt, (1997, 12, 24, 0, 0, 0))
 print len(l) == 10, 10, len(l)
@@ -249,6 +269,8 @@
 show(csel)
 
 s = get_selector(dt, sel)
+csel = get_selectors_from_selector(s)
+show(csel)
 
 l = s.materialise(dt, (1997, 12, 24, 0, 0, 0))
 print len(l) == 17, 17, len(l)
@@ -269,6 +291,8 @@
 show(csel)
 
 s = get_selector(dt, sel)
+csel = get_selectors_from_selector(s)
+show(csel)
 
 l = s.materialise(dt, (1997, 12, 24, 0, 0, 0))
 print len(l) == 17, 17, len(l)
@@ -289,6 +313,8 @@
 show(csel)
 
 s = get_selector(dt, sel)
+csel = get_selectors_from_selector(s)
+show(csel)
 
 l = s.materialise(dt, (1998, 2, 20, 0, 0, 0))
 print len(l) == 13, 13, len(l)
@@ -310,6 +336,8 @@
 show(csel)
 
 s = get_selector(dt, sel)
+csel = get_selectors_from_selector(s)
+show(csel)
 
 l = s.materialise(dt, (1997, 10, 7, 9, 0, 0))
 print len(l) == 10, 10, len(l)
@@ -332,6 +360,8 @@
 show(csel)
 
 s = get_selector(dt, sel)
+csel = get_selectors_from_selector(s)
+show(csel)
 
 l = s.materialise(dt, (1997, 12, 24, 0, 0, 0))
 print len(l) == 10, 10, len(l)
@@ -353,6 +383,8 @@
 show(csel)
 
 s = get_selector(dt, sel)
+csel = get_selectors_from_selector(s)
+show(csel)
 
 l = s.materialise(dt, (1997, 12, 24, 0, 0, 0))
 print len(l) == 25, 25, len(l)
@@ -375,6 +407,8 @@
 show(csel)
 
 s = get_selector(dt, sel)
+csel = get_selectors_from_selector(s)
+show(csel)
 
 l = s.materialise(dt, (1997, 12, 24, 0, 0, 0))
 print len(l) == 8, 8, len(l)
@@ -397,6 +431,8 @@
 show(csel)
 
 s = get_selector(dt, sel)
+csel = get_selectors_from_selector(s)
+show(csel)
 
 l = s.materialise(dt, (1998, 12, 24, 0, 0, 0))
 print len(l) == 10, 10, len(l)
@@ -418,6 +454,8 @@
 show(csel)
 
 s = get_selector(dt, sel)
+csel = get_selectors_from_selector(s)
+show(csel)
 
 l = s.materialise(dt, (1997, 12, 24, 0, 0, 0))
 print len(l) == 4, 4, len(l)
@@ -440,6 +478,8 @@
 show(csel)
 
 s = get_selector(dt, sel)
+csel = get_selectors_from_selector(s)
+show(csel)
 
 l = s.materialise(dt, (1998, 12, 24, 0, 0, 0))
 print len(l) == 10, 10, len(l)
@@ -462,6 +502,8 @@
 show(csel)
 
 s = get_selector(dt, sel)
+csel = get_selectors_from_selector(s)
+show(csel)
 
 l = s.materialise(dt, (1998, 12, 24, 0, 0, 0))
 print len(l) == 6, 6, len(l)
@@ -484,6 +526,8 @@
 show(csel)
 
 s = get_selector(dt, sel)
+csel = get_selectors_from_selector(s)
+show(csel)
 
 l = s.materialise(dt, (1998, 12, 24, 0, 0, 0))
 print len(l) == 6, 6, len(l)
@@ -506,6 +550,8 @@
 show(csel)
 
 s = get_selector(dt, sel)
+csel = get_selectors_from_selector(s)
+show(csel)
 
 l = s.materialise(dt, (1998, 12, 24, 0, 0, 0))
 print len(l) == 10, 10, len(l)
@@ -528,6 +574,8 @@
 show(csel)
 
 s = get_selector(dt, sel)
+csel = get_selectors_from_selector(s)
+show(csel)
 
 l = s.materialise(dt, (1998, 12, 24, 0, 0, 0))
 print len(l) == 10, 10, len(l)
@@ -550,6 +598,8 @@
 show(csel)
 
 s = get_selector(dt, sel)
+csel = get_selectors_from_selector(s)
+show(csel)
 
 l = s.materialise(dt, (1999, 12, 24, 0, 0, 0))
 print len(l) == 10, 10, len(l)
@@ -571,6 +621,8 @@
 show(csel)
 
 s = get_selector(dt, sel)
+csel = get_selectors_from_selector(s)
+show(csel)
 
 l = s.materialise(dt, (1998, 4, 1, 0, 0, 0))
 print len(l) == 18, 18, len(l)
@@ -593,6 +645,8 @@
 show(csel)
 
 s = get_selector(dt, sel)
+csel = get_selectors_from_selector(s)
+show(csel)
 
 l = s.materialise(dt, (2001, 12, 24, 0, 0, 0))
 print len(l) == 10, 10, len(l)
@@ -615,6 +669,8 @@
 show(csel)
 
 s = get_selector(dt, sel)
+csel = get_selectors_from_selector(s)
+show(csel)
 
 l = s.materialise(dt, (2003, 12, 24, 0, 0, 0))
 print len(l) == 10, 10, len(l)
@@ -637,6 +693,8 @@
 show(csel)
 
 s = get_selector(dt, sel)
+csel = get_selectors_from_selector(s)
+show(csel)
 
 l = s.materialise(dt, (2006, 2, 1, 0, 0, 0))
 print len(l) == 10, 10, len(l)
@@ -658,6 +716,8 @@
 show(csel)
 
 s = get_selector(dt, sel)
+csel = get_selectors_from_selector(s)
+show(csel)
 
 l = s.materialise(dt, (1999, 12, 24, 0, 0, 0))
 print len(l) == 3, 3, len(l)
@@ -681,6 +741,8 @@
 show(csel)
 
 s = get_selector(dt, sel)
+csel = get_selectors_from_selector(s)
+show(csel)
 
 l = s.materialise(dt, (1999, 12, 24, 0, 0, 0))
 print len(l) == 3, 3, len(l)
@@ -704,6 +766,8 @@
 show(csel)
 
 s = get_selector(dt, sel)
+csel = get_selectors_from_selector(s)
+show(csel)
 
 l = s.materialise(dt, (1999, 12, 24, 0, 0, 0))
 print len(l) == 11, 11, len(l)
@@ -726,6 +790,8 @@
 show(csel)
 
 s = get_selector(dt, sel)
+csel = get_selectors_from_selector(s)
+show(csel)
 
 l = s.materialise(dt, (1999, 12, 24, 0, 0, 0))
 print len(l) == 39, 39, len(l)
@@ -748,6 +814,8 @@
 show(csel)
 
 s = get_selector(dt, sel)
+csel = get_selectors_from_selector(s)
+show(csel)
 
 l = s.materialise(dt, (2000, 12, 24, 0, 0, 0))
 print len(l) == 6, 6, len(l)
@@ -770,6 +838,8 @@
 show(csel)
 
 s = get_selector(dt, sel)
+csel = get_selectors_from_selector(s)
+show(csel)
 
 l = s.materialise(dt, (1998, 6, 30, 0, 0, 0))
 print len(l) == 10, 10, len(l)
@@ -793,6 +863,8 @@
 show(csel)
 
 s = get_selector(dt, sel)
+csel = get_selectors_from_selector(s)
+show(csel)
 
 l = s.materialise(dt, (2004, 12, 24, 0, 0, 0))
 print len(l) == 3, 3, len(l)
@@ -816,6 +888,8 @@
 show(csel)
 
 s = get_selector(dt, sel)
+csel = get_selectors_from_selector(s)
+show(csel)
 
 l = s.materialise(dt, (1997, 12, 24, 0, 0, 0))
 print len(l) == 3, 3, len(l)
@@ -840,6 +914,8 @@
 show(csel)
 
 s = get_selector(dt, sel)
+csel = get_selectors_from_selector(s)
+show(csel)
 
 l = s.materialise(dt, (1998, 4, 1, 0, 0, 0))
 print len(l) == 7, 7, len(l)
@@ -858,6 +934,8 @@
 show(csel)
 
 s = get_selector(dt, sel)
+csel = get_selectors_from_selector(s)
+show(csel)
 
 l = s.materialise(dt, (2019, 1, 1))
 print len(l) == 37, 37, len(l)
@@ -875,6 +953,8 @@
 show(csel)
 
 s = get_selector(dt, sel)
+csel = get_selectors_from_selector(s)
+show(csel)
 
 l = s.materialise(dt, (2019, 1, 1))
 print len(l) == 32, 32, len(l)
@@ -892,6 +972,8 @@
 show(csel)
 
 s = get_selector(dt, sel)
+csel = get_selectors_from_selector(s)
+show(csel)
 
 l = s.materialise(dt, (2018, 1, 1))
 print len(l) == 18, 18, len(l)
diff -r 9f507afaa71b -r d39a2232c737 vRecurrence.py
--- a/vRecurrence.py	Sun Dec 03 17:13:17 2017 +0100
+++ b/vRecurrence.py	Sun Dec 03 19:19:14 2017 +0100
@@ -488,24 +488,32 @@
     from_dt = get_next(iter_dt)
     from_sel = get_next(iter_sel)
     have_sel = False
+    held_dt = []
 
     # Consume from both lists, merging entries.
 
-    while from_dt and from_sel:
-        _level = from_dt.level
+    while from_sel:
         level = from_sel.level
 
         # Datetime value at wider resolution.
 
-        if _level < level:
+        if from_dt and from_dt.level < level:
+            held_dt.append(from_dt)
             from_dt = get_next(iter_dt)
 
         # Qualifier at wider or same resolution as datetime value.
 
         else:
             if not have_sel:
-                add_initial_selector(from_sel, level, l)
-                have_sel = True
+                have_sel = add_initial_selector(from_sel, level, l)
+
+            # Introduce any held datetime values, if appropriate.
+
+            elif can_restrict_selector(from_sel):
+                for from_held_dt in held_dt:
+                    add_datetime_selector(from_held_dt, l)
+
+            held_dt = []
 
             # Add the qualifier to the combined list.
 
@@ -513,7 +521,7 @@
 
             # Datetime value at same resolution.
 
-            if _level == level:
+            if from_dt and from_dt.level == level:
                 from_dt = get_next(iter_dt)
 
             # Get the next qualifier.
@@ -523,45 +531,44 @@
     # Complete the list by adding remaining datetime enumerators.
 
     while from_dt:
-
-        # Ignore datetime values that conflict with day-level qualifiers.
-
-        if not l or from_dt.level != freq["DAILY"] or \
-           l[-1].level not in daylevels:
-
-            l.append(from_dt)
-
+        add_datetime_selector(from_dt, l)
         from_dt = get_next(iter_dt)
 
-    # Complete the list by adding remaining qualifiers.
+    return l
 
-    while from_sel:
-        if not have_sel:
-            add_initial_selector(from_sel, level, l)
-            have_sel = True
+def can_restrict_selector(from_sel):
 
-        # Add the qualifier to the combined list.
-
-        l.append(from_sel)
+    "Return whether 'from_sel' can be restricted using datetime information."
 
-        # Get the next qualifier.
-
-        from_sel = get_next(iter_sel)
-
-    return l
+    return not isinstance(from_sel, Pattern) and from_sel.qualifier != "BYDAY"
 
 def add_initial_selector(from_sel, level, l):
 
     """
-    Take the first selector 'from_sel' at the given resolution 'level', using it
-    to create an initial selector, adding it to the combined list 'l' if
-    required.
+    Take the selector 'from_sel' at the given resolution 'level', using it to
+    create an initial selector, adding it to the combined list 'l' if required.
+
+    Return whether a frequency selector has been introduced or if 'from_sel' is
+    such a selector.
     """
 
     if isinstance(from_sel, Enum) and level > 0:
         parent_level = enum_parent_levels[level]
         repeat = Pattern(parent_level, {"interval" : 1}, freq_levels[parent_level])
         l.append(repeat)
+        return True
+
+    return isinstance(from_sel, Pattern)
+
+def add_datetime_selector(from_dt, l):
+
+    """
+    Take the selector 'from_dt' and add it to the list 'l' if it does not
+    conflict with any day-level qualifiers already in 'l'.
+    """
+
+    if not l or from_dt.level != freq["DAILY"] or l[-1].level not in daylevels:
+        l.append(from_dt)
 
 def get_multiple(qualifier):
 
@@ -1531,4 +1538,13 @@
         rule = (rule or "").split(";")
     return make_selectors(get_qualifiers(rule))
 
+def get_selectors_from_selector(selector):
+
+    "Return the chain of selectors from 'selector', useful for debugging."
+
+    if selector.selecting:
+        return [selector] + get_selectors_from_selector(selector.selecting)
+    else:
+        return [selector]
+
 # vim: tabstop=4 expandtab shiftwidth=4