# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1373839200 -7200
# Node ID deb6bdca9d1b242bd1c7b9ec5b6d2d3724313ee8
# Parent  9fc4e33b0b611865de674a5dd5b55091cf4da77b
Changed the specific recurrence grammar so that concrete datetimes are not
qualified by other specific recurrences.
Imposed resolution restrictions on the limits of repeating recurrences.

diff -r 9fc4e33b0b61 -r deb6bdca9d1b RecurrenceSupport.py
--- a/RecurrenceSupport.py	Sun Jul 14 21:11:12 2013 +0200
+++ b/RecurrenceSupport.py	Mon Jul 15 00:00:00 2013 +0200
@@ -11,19 +11,23 @@
 
   recurrence = <specific-recurrence> | <repeating-recurrence>
 
-  specific-recurrence = ( ( the <qualifier> <interval> ) | <concrete-datetime> )
+  specific-recurrence = ( the <qualifier> <interval> | <month-label> )
                         [ in <specific-recurrence> ]
+                        | <concrete-datetime>
 
   repeating-recurrence = every [ <qualifier> ] <interval>
                          [ from <specific-recurrence> ]
                          [ until <specific-recurrence> ]
 
-  concrete-datetime = <datetime> | <month> | <year>
+  concrete-datetime = <datetime> | <year>
 
 Constraints:
 
   repeating-recurrence: if <qualifier> is not "single":
                         from and/or until must be specified
+
+                        from and/or until <specific-recurrence> resolutions
+                        must be compatible with the repeating-recurrence
 """
 
 from DateSupport import weekday_labels, weekday_labels_verbose, month_labels, \
@@ -148,6 +152,12 @@
         else:
             return t
 
+    def have_one_of(self, tokens):
+        if self.end:
+            return False
+        t = self.tokens[-1]
+        return t in tokens
+
     def _next(self):
         t = self.iterator.next()
         self.tokens.append(t)
@@ -203,9 +213,11 @@
             self.until_datetime and ", until_datetime=%r" % self.until_datetime or "",
             self.qualified_by and ", qualified_by=%r" % self.qualified_by or "")
 
-    def select(self):
-
-        "Select occurrences using this object's criteria."
+    def get_resolution(self):
+        if self.qualified_by:
+            return self.qualified_by.get_resolution()
+        else:
+            return self.interval_level
 
 # Parsing functions.
 
@@ -237,7 +249,8 @@
     """
     Using the incoming 'words' and given the 'current' selector, parse a
     recurrence that can be either a repeating recurrence (starting with "every")
-    or a specific recurrence (starting with "the").
+    or a specific recurrence (starting with "the") or a concrete datetime
+    reference.
 
     The active selector is returned as a result of parsing the recurrence.
     """
@@ -247,10 +260,8 @@
         parseRepeatingRecurrence(words, current)
         words.want()
         return current
-    elif words.have("the"):
+    else:
         return parseSpecificRecurrence(words, current)
-    else:
-        return parseConcreteDateTime(words, current)
 
 def parseConcreteDateTime(words, current):
 
@@ -284,13 +295,6 @@
         words.want()
         return current
 
-    # Detect month labels.
-
-    elif word in month_labels:
-        current.add_datetime("month", intervals["month"], word)
-        words.want()
-        return current
-
     raise ParseError, words.tokens
 
 def parseSpecificRecurrence(words, current):
@@ -300,32 +304,45 @@
     return a specific recurrence.
     """
 
+    word = words.have()
+
+    # Detect month labels.
+
+    if word in month_labels:
+        current.add_details("the", word, month_labels.index(word) + 1, "month", intervals["month"])
+
     # Handle the qualifier and interval.
 
-    qualifier = words.next()
-    qualifier_level = isSpecificQualifier(qualifier)
-    if not qualifier_level:
-        raise ParseError, words.tokens
-    interval = words.next()
-    interval_level = intervals.get(interval)
-    if not interval_level:
-        raise ParseError, words.tokens
+    elif word == "the":
+        qualifier = words.next()
+        qualifier_level = isSpecificQualifier(qualifier)
+        if not qualifier_level:
+            raise ParseError, words.tokens
+        interval = words.next()
+        interval_level = intervals.get(interval)
+        if not interval_level:
+            raise ParseError, words.tokens
 
-    current.add_details("the", qualifier, qualifier_level, interval, interval_level)
+        current.add_details("the", qualifier, qualifier_level, interval, interval_level)
+
+        # Detect the intervals becoming smaller.
 
-    # Detect the intervals becoming smaller.
+        if current.qualified_by and current.interval_level < current.qualified_by.interval_level:
+            raise ParseError, words.tokens
 
-    if current.qualified_by and current.interval_level < current.qualified_by.interval_level:
-        raise ParseError, words.tokens
+        # Define selectors that are being qualified by the above qualifier and
+        # interval, returning the least specific selector.
 
-    # Define selectors that are being qualified by the above qualifier and
-    # interval, returning the least specific selector.
+        words.want()
+        if words.have("in"):
+            current = Selector(current)
+            words.want()
+            current = parseSpecificRecurrence(words, current)
 
-    words.want()
-    if words.have("in"):
-        current = Selector(current)
-        words.need("the")
-        current = parseSpecificRecurrence(words, current)
+    # Handle concrete datetime details.
+
+    else:
+        current = parseConcreteDateTime(words, current)
 
     return current
 
@@ -384,21 +401,27 @@
     from_datetime = until_datetime = None
 
     if words.have("from"):
+        words.want()
         from_datetime = Selector()
-        words.next()
-        if words.have("the"):
-            from_datetime = parseSpecificRecurrence(words, from_datetime)
-        else:
-            from_datetime = parseConcreteDateTime(words, from_datetime)
+        from_datetime = parseSpecificRecurrence(words, from_datetime)
+
+        # Detect the limit interval differing from the selector.
+
+        if current.interval_level != from_datetime.get_resolution():
+            raise ParseError, words.tokens
+
         current.set_from(from_datetime)
 
     if words.have("until"):
+        words.want()
         until_datetime = Selector()
-        words.next()
-        if words.have("the"):
-            until_datetime = parseSpecificRecurrence(words, until_datetime)
-        else:
-            until_datetime = parseConcreteDateTime(words, until_datetime)
+        until_datetime = parseSpecificRecurrence(words, until_datetime)
+
+        # Detect the limit interval differing from the selector.
+
+        if current.interval_level != until_datetime.get_resolution():
+            raise ParseError, words.tokens
+
         current.set_until(until_datetime)
 
     # Where the selector refers to a interval repeating at a frequency greater
diff -r 9fc4e33b0b61 -r deb6bdca9d1b tests/test_recurrence.py
--- a/tests/test_recurrence.py	Sun Jul 14 21:11:12 2013 +0200
+++ b/tests/test_recurrence.py	Mon Jul 15 00:00:00 2013 +0200
@@ -7,50 +7,98 @@
 s = "every single day of 2013"
 print s
 print "->", getRecurrence(s)
+
 s = "every Tuesday of 2013"
 print s
 print "->", getRecurrence(s)
+
 s = "every Wednesday of every March"
 print s
 print "->", getRecurrence(s)
-s = "every single day of every other February from 2013"
+
+s = "every single day of every other February from 2013-02"
 print s
 print "->", getRecurrence(s)
-s = "every single day of every other February from 2013-02-01"
-print s
-print "->", getRecurrence(s)
+
 s = "every other day from 2013-02-01"
 print s
 print "->", getRecurrence(s)
-s = "every single day of the second month"
+
+s = "every single day of the second month of 2013"
 print s
 print "->", getRecurrence(s)
+
+s = "every single day of the second month in 2013"
+print s
+print "->", getRecurrence(s)
+
 s = "every single day of the second month of every year"
 print s
 print "->", getRecurrence(s)
+
 s = "every other day from the first day of every other month from the third month of every year"
 print s
 print "->", getRecurrence(s)
-s = "the second day of every other month from the first month"
+
+s = "the second day of every other month from the first month of 2012"
 print s
 print "->", getRecurrence(s)
+
 s = "the second hour in the second day in the second month of every year"
 print s
 print "->", getRecurrence(s)
+
 s = "every day from the second day until the 10th day of every other month until the fifth month"
 print s
 print "->", getRecurrence(s)
+
 s = "every day from the 10th day in the second month until the 10th day in the 10th month of every third month from the first month"
 print s
 print "->", getRecurrence(s)
-s = "every day of every third month from the 10th day in the second month until the 10th day in the 10th month"
-print s
-print "->", getRecurrence(s)
 
 # Bad recurrences.
 
 print
 
+# Incomplete specification.
+
+s = "every single day of the second month"
+print s
+try:
+    print "->", getRecurrence(s)
+except ParseError, exc:
+    print exc
+
+s = "the second day of every other month from the first month"
+print s
+try:
+    print "->", getRecurrence(s)
+except ParseError, exc:
+    print exc
+
+# Limits do not match recurrence.
+
+s = "every single day of every other February from 2013"
+print s
+try:
+    print "->", getRecurrence(s)
+except ParseError, exc:
+    print exc
+
+s = "every single day of every other February from 2013-02-01"
+print s
+try:
+    print "->", getRecurrence(s)
+except ParseError, exc:
+    print exc
+
+s = "every day of every third month from the 10th day in the second month until the 10th day in the 10th month"
+print s
+try:
+    print "->", getRecurrence(s)
+except ParseError, exc:
+    print exc
+
 # No start or end points.
 
 s = "every other day of every other month"