clock: add weeks-numbering option for configurable CW calculation

The iso8601 flag previously controlled both the calendar grid layout
and the week number format as a coupled boolean. This adds a new
weeks-numbering option (iso/monday/sunday) that explicitly overrides
just the week number calculation method, independent of iso8601 and
locale settings. Existing behaviour is fully preserved when the option
is not set.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

include/modules/clock.hpp

@@ -12,6 +12,7 @@ const std::string kOrdPlaceholder{"ordinal_date"};
 
 enum class CldMode { MONTH, YEAR };
 enum class WS { LEFT, RIGHT, HIDDEN };
+enum class WeekNumbering { LOCALE, ISO, MONDAY, SUNDAY };
 
 class Clock final : public ALabel {
  public:
@@ -50,7 +51,8 @@ class Clock final : public ALabel {
   std::string cldMonCached_;           // calendar Month mode. Cached calendar
   date::day cldBaseDay_{0};      // calendar Cached day. Is used when today is changing(midnight)
   std::string cldText_{""};      // calendar text to print
-  bool iso8601Calendar_{false};  // whether the calendar is in ISO8601
+  bool iso8601Calendar_{false};          // whether the calendar is in ISO8601
+  WeekNumbering weekNumbering_{WeekNumbering::LOCALE};  // week number calculation method
   CldMode cldMode_{CldMode::MONTH};
   auto get_calendar(const date::year_month_day& today, const date::year_month_day& ymd,
                     const date::time_zone* tz) -> const std::string;

man/waybar-clock.5.scd

@@ -138,6 +138,13 @@ View all valid format options in *strftime(3)* or have a look https://en.cpprefe
 :[ When enabled, the calendar follows the ISO 8601 standard: weeks begin on
    Monday, and the first week of the year is numbered 1. The default week format is
    '{:%V}'.
+|[ *weeks-numbering*
+:[ string
+:[
+:[ Override the week number calculation method, independent of *iso8601* and
+   locale settings. Possible values: *iso* (ISO 8601, {:%V}), *monday*
+   (Monday-based, {:%W}), *sunday* (Sunday-based, {:%U}). When not set, the
+   method is derived from *iso8601* or the locale.
 
 3. Addressed by *clock: calendar: format*
 [- *Option*
@@ -155,8 +162,9 @@ View all valid format options in *strftime(3)* or have a look https://en.cpprefe
 |[ *weeks*
 :[ string
 :[ *{:%U}*
-:[ Format is applied to week numbers. When weekday format is not provided then
-   is used default format: '{:%W}' when week starts with Monday, '{:%U}' otherwise
+:[ Format is applied to week numbers. The *{}* placeholder is replaced with the
+   format determined by *weeks-numbering* (if set), otherwise by *iso8601* or the
+   locale: '{:%V}' for ISO 8601, '{:%W}' when week starts with Monday, '{:%U}' otherwise
 |[ *weekdays*
 :[ string
 :[

src/modules/clock.cpp

@@ -81,6 +81,20 @@ waybar::modules::Clock::Clock(const std::string& id, const Json::Value& config)
       iso8601Calendar_ = config_[kCldPlaceholder]["iso8601"].asBool();
     }
 
+    if (config_[kCldPlaceholder]["weeks-numbering"].isString()) {
+      const std::string wn{config_[kCldPlaceholder]["weeks-numbering"].asString()};
+      const std::map<std::string, WeekNumbering> wnModes{{"iso", WeekNumbering::ISO},
+                                                         {"monday", WeekNumbering::MONDAY},
+                                                         {"sunday", WeekNumbering::SUNDAY}};
+      if (wnModes.find(wn) != wnModes.end())
+        weekNumbering_ = wnModes.at(wn);
+      else
+        spdlog::warn(
+            "Clock calendar configuration weeks-numbering \"{}\" is not recognized. "
+            "Locale default is used instead",
+            wn);
+    }
+
     if (config_[kCldPlaceholder]["weeks-pos"].isString()) {
       if (config_[kCldPlaceholder]["weeks-pos"].asString() == "left") cldWPos_ = WS::LEFT;
       if (config_[kCldPlaceholder]["weeks-pos"].asString() == "right") cldWPos_ = WS::RIGHT;
@@ -104,18 +118,27 @@ waybar::modules::Clock::Clock(const std::string& id, const Json::Value& config)
       cldBaseDay_ = year_month_day{floor<days>(local_time)}.day();
     } else
       fmtMap_.insert({3, "{}"});
+    const auto weekFmt = [this]() -> std::string {
+      switch (weekNumbering_) {
+        case WeekNumbering::ISO:
+          return "{:%V}";
+        case WeekNumbering::MONDAY:
+          return "{:%W}";
+        case WeekNumbering::SUNDAY:
+          return "{:%U}";
+        default:
+          return iso8601Calendar_ ? "{:%V}"
+                                  : ((first_day_of_week() == Monday) ? "{:%W}" : "{:%U}");
+      }
+    }();
     if (config_[kCldPlaceholder]["format"]["weeks"].isString() && cldWPos_ != WS::HIDDEN) {
-      const auto defaultFmt =
-          iso8601Calendar_ ? "{:%V}" : ((first_day_of_week() == Monday) ? "{:%W}" : "{:%U}");
       fmtMap_.insert({4, std::regex_replace(config_[kCldPlaceholder]["format"]["weeks"].asString(),
-                                            std::regex("\\{\\}"), defaultFmt)});
+                                            std::regex("\\{\\}"), weekFmt)});
       Glib::ustring tmp{std::regex_replace(fmtMap_[4], std::regex("</?[^>]+>|\\{.*\\}"), "")};
       cldWnLen_ += tmp.size();
     } else {
       if (cldWPos_ != WS::HIDDEN) {
-        const auto defaultFmt =
-            iso8601Calendar_ ? "{:%V}" : ((first_day_of_week() == Monday) ? "{:%W}" : "{:%U}");
-        fmtMap_.insert({4, defaultFmt});
+        fmtMap_.insert({4, weekFmt});
       } else {
         cldWnLen_ = 0;
       }