Support iso-year-week-day in calendar_leap_year()

DESCRIPTION

@@ -22,7 +22,7 @@ Depends:
 Imports:
     cli (>= 3.6.1),
     rlang (>= 1.1.0),
-    tzdb (>= 0.3.0),
+    tzdb (>= 0.3.0.9000),
     vctrs (>= 0.6.1)
 Suggests: 
     covr,
@@ -35,7 +35,7 @@ Suggests:
     withr
 LinkingTo: 
     cpp11 (>= 0.4.3),
-    tzdb (>= 0.3.0)
+    tzdb (>= 0.3.0.9000)
 VignetteBuilder: 
     knitr
 Config/Needs/website:
@@ -46,3 +46,5 @@ Encoding: UTF-8
 LazyData: true
 Roxygen: list(markdown = TRUE)
 RoxygenNote: 7.2.3
+Remotes:
+    r-lib/tzdb

NAMESPACE

@@ -209,6 +209,7 @@ S3method(calendar_is_valid_precision,clock_year_month_weekday)
 S3method(calendar_is_valid_precision,clock_year_quarter_day)
 S3method(calendar_is_valid_precision,clock_year_week_day)
 S3method(calendar_leap_year,clock_calendar)
+S3method(calendar_leap_year,clock_iso_year_week_day)
 S3method(calendar_leap_year,clock_year_day)
 S3method(calendar_leap_year,clock_year_month_day)
 S3method(calendar_leap_year,clock_year_month_weekday)

NEWS.md

@@ -8,7 +8,8 @@
   the Epidemiological calendar used by the US CDC guidelines (similar to what
   is supported by `lubridate::epiweek()` and `lubridate::epiyear()`) (#110).
 
-* `calendar_leap_year()` now supports the year-quarter-day calendar (#332).
+* `calendar_leap_year()` now supports the year-quarter-day and iso-year-week-day
+  calendars (#332, #333).
 
 * Documented clock's current stance on leap seconds in the FAQ vignette (clock
   ignores them like POSIXct) (#309).

R/calendar.R

@@ -72,16 +72,20 @@ cast_calendar_to_calendar <- function(x, to, ...) {
 #'
 #' - [year_month_weekday()]: February has a weekday that occurs 5 times.
 #'
-#' - [year_week_day()]: There are 53 weeks in the year.
+#' - [year_week_day()]: There are 53 weeks in the year, resulting in 371
+#'   days in the year.
 #'
-#' - [year_day()]: There are 366 days in the year.
+#' - [iso_year_week_day()]: There are 53 weeks in the year, resulting in 371
+#'   days in the year.
 #'
 #' - [year_quarter_day()]: One of the quarters has 1 more day than normal (the
 #'   quarter with an extra day depends on the `start` used, but will always be
 #'   the same for a particular `start`). This aligns with Gregorian leap years
 #'   for all `start`s except February, in which case the leap year is always 1
 #'   year after the Gregorian leap year.
 #'
+#' - [year_day()]: There are 366 days in the year.
+#'
 #' @param x `[calendar]`
 #'
 #'   A calendar type to detect leap years in.

R/cpp11.R

@@ -316,6 +316,10 @@ iso_year_week_day_minus_iso_year_week_day_cpp <- function(x, y, precision_int) {
   .Call(`_clock_iso_year_week_day_minus_iso_year_week_day_cpp`, x, y, precision_int)
 }
 
+iso_year_week_day_leap_year_cpp <- function(year) {
+  .Call(`_clock_iso_year_week_day_leap_year_cpp`, year)
+}
+
 clock_get_year_max <- function() {
   .Call(`_clock_clock_get_year_max`)
 }

R/iso-year-week-day.R

@@ -786,6 +786,14 @@ as.character.clock_iso_year_week_day <- function(x, ...) {
 
 # ------------------------------------------------------------------------------
 
+#' @export
+calendar_leap_year.clock_iso_year_week_day <- function(x) {
+  year <- get_year(x)
+  iso_year_week_day_leap_year_cpp(year)
+}
+
+# ------------------------------------------------------------------------------
+
 #' Grouping: iso-year-week-day
 #'
 #' @description

src/cpp11.cpp

@@ -558,6 +558,13 @@ extern "C" SEXP _clock_iso_year_week_day_minus_iso_year_week_day_cpp(SEXP x, SEX
     return cpp11::as_sexp(iso_year_week_day_minus_iso_year_week_day_cpp(cpp11::as_cpp<cpp11::decay_t<cpp11::list_of<cpp11::integers>>>(x), cpp11::as_cpp<cpp11::decay_t<cpp11::list_of<cpp11::integers>>>(y), cpp11::as_cpp<cpp11::decay_t<const cpp11::integers&>>(precision_int)));
   END_CPP11
 }
+// iso-year-week-day.cpp
+cpp11::writable::logicals iso_year_week_day_leap_year_cpp(const cpp11::integers& year);
+extern "C" SEXP _clock_iso_year_week_day_leap_year_cpp(SEXP year) {
+  BEGIN_CPP11
+    return cpp11::as_sexp(iso_year_week_day_leap_year_cpp(cpp11::as_cpp<cpp11::decay_t<const cpp11::integers&>>(year)));
+  END_CPP11
+}
 // limits.cpp
 int clock_get_year_max();
 extern "C" SEXP _clock_clock_get_year_max() {
@@ -1018,6 +1025,7 @@ static const R_CallMethodDef CallEntries[] = {
     {"_clock_invalid_resolve_year_month_weekday_cpp",               (DL_FUNC) &_clock_invalid_resolve_year_month_weekday_cpp,                3},
     {"_clock_invalid_resolve_year_quarter_day_cpp",                 (DL_FUNC) &_clock_invalid_resolve_year_quarter_day_cpp,                  4},
     {"_clock_invalid_resolve_year_week_day_cpp",                    (DL_FUNC) &_clock_invalid_resolve_year_week_day_cpp,                     4},
+    {"_clock_iso_year_week_day_leap_year_cpp",                      (DL_FUNC) &_clock_iso_year_week_day_leap_year_cpp,                       1},
     {"_clock_iso_year_week_day_minus_iso_year_week_day_cpp",        (DL_FUNC) &_clock_iso_year_week_day_minus_iso_year_week_day_cpp,         3},
     {"_clock_iso_year_week_day_plus_duration_cpp",                  (DL_FUNC) &_clock_iso_year_week_day_plus_duration_cpp,                   4},
     {"_clock_iso_year_week_day_restore",                            (DL_FUNC) &_clock_iso_year_week_day_restore,                             2},

src/iso-year-week-day.cpp

@@ -414,3 +414,24 @@ iso_year_week_day_minus_iso_year_week_day_cpp(cpp11::list_of<cpp11::integers> x,
 
   never_reached("iso_year_week_day_minus_iso_year_week_day_cpp");
 }
+
+// -----------------------------------------------------------------------------
+
+[[cpp11::register]]
+cpp11::writable::logicals
+iso_year_week_day_leap_year_cpp(const cpp11::integers& year) {
+  const r_ssize size = year.size();
+  cpp11::writable::logicals out(size);
+
+  for (r_ssize i = 0; i < size; ++i) {
+    const int elt = year[i];
+
+    if (elt == r_int_na) {
+      out[i] = r_lgl_na;
+    } else {
+      out[i] = iso_week::year{elt}.is_leap();
+    }
+  }
+
+  return out;
+}

tests/testthat/test-iso-year-week-day.R

@@ -386,6 +386,27 @@ test_that("can compute week end", {
   expect_identical(calendar_end(x, "week"), expect)
 })
 
+# ------------------------------------------------------------------------------
+# calendar_leap_year()
+
+test_that("can detect leap years", {
+  # Exactly 71 leap weeks for any 400 year cycle
+  start <- 1900L
+
+  while (start < 2000L) {
+    # `- 1L` to have exactly 400 years considered in the range since both
+    # `start` and `end` are included by `seq()`
+    end <- start + 400L - 1L
+    x <- iso_year_week_day(seq(start, end))
+    expect_identical(sum(calendar_leap_year(x)), 71L)
+    start <- start + 1L
+  }
+})
+
+test_that("`NA` propagates", {
+  expect_identical(calendar_leap_year(iso_year_week_day(NA)), NA)
+})
+
 # ------------------------------------------------------------------------------
 # calendar_count_between()