Merge pull request #173 from isovector/master

Add "week of year" expression

doc/arbtt.xml

@@ -298,6 +298,9 @@
       Expression <literal>day of week $date</literal> evaluates to an integer,
       from 1 to 7, corresponding to the day of week, Monday is 1, Sunday is 7.
       These expressions can be compared to integers.
+      Expression <literal>week of year $date</literal> evaluates to an integer,
+      from 0 to 53, corresponding to the week of year. January 1 falls in week 0.
+      These expressions can be compared to integers.
     </para>
 
     <para>
@@ -452,6 +455,7 @@
         <rhs> <quote>$idle</quote> </rhs>
         <rhs> <quote>day of week</quote> <nonterminal def="#g-date" /> </rhs>
         <rhs> <quote>day of month</quote> <nonterminal def="#g-date" /> </rhs>
+        <rhs> <quote>week of year</quote> <nonterminal def="#g-date" /> </rhs>
         <rhs> <quote>month</quote> <nonterminal def="#g-date" /> </rhs>
         <rhs> <quote>year</quote> <nonterminal def="#g-date" /> </rhs>
         <rhs> number literal </rhs>

src/Categorize.hs

@@ -222,6 +222,7 @@ parseCondExpr = buildExpressionParser [
                 [ Prefix (reservedOp lang "!" >> return checkNot) ],
                 [ Prefix (reserved lang "day of week" >> return evalDayOfWeek)
                 , Prefix (reserved lang "day of month" >> return evalDayOfMonth)
+                , Prefix (reserved lang "week of year" >> return evalWeekOfYear)
                 , Prefix (reserved lang "month" >> return evalMonth)
                 , Prefix (reserved lang "year" >> return evalYear)
                 , Prefix (reserved lang "format" >> return formatDate) ],
@@ -354,6 +355,15 @@ evalDayOfMonth cp = Left $ printf
   "Cannot apply day of month to an expression of type %s, only to $date."
   (cpType cp)
 
+-- Week of year is an integer in [0..53].
+evalWeekOfYear :: CondPrim -> Erring CondPrim
+evalWeekOfYear (CondDate df) = Right $ CondInteger $ \ctx ->
+  let tz = zonedTimeZone (cCurrentTime ctx) in
+  (toInteger . snd3 . toWeekDate . localDay . utcToLocalTime tz) `fmap` df ctx
+evalWeekOfYear cp = Left $ printf
+  "Cannot apply week of year to an expression of type %s, only to $date."
+  (cpType cp)
+
 -- Month is an integer in [1..12].
 evalMonth :: CondPrim -> Erring CondPrim
 evalMonth (CondDate df) = Right $ CondInteger $ \ctx ->