Add support for named months and wdays

README.md

@@ -69,7 +69,6 @@ Calculates the last 'n' occurrences of the cron job until a given end time.\
 
 ## Unsupported features
 
-- Named DOW and months (SUN-SAT, JAN-DEC)
 - Joining characters , - /
 - Predefined definitions (@yearly, @monthly, @weekly, @daily, @midnight, @hourly)
 

lib/cron_calc.rb

@@ -2,6 +2,7 @@
 
 require_relative 'cron_calc/version'
 require 'time'
+require 'debug'
 
 # The CronCalc is gem-wrapper module for the Parser class
 module CronCalc
@@ -22,7 +23,18 @@ class Parser
       hours: 0..23,
       days: 1..31,
       months: 1..12,
-      dows: 0..7
+      wdays: 0..6
+    }.freeze
+
+    WDAYS = {
+      'SUN' => '0', 'MON' => '1', 'TUE' => '2', 'WED' => '3',
+      'THU' => '4', 'FRI' => '5', 'SAT' => '6'
+    }.freeze
+
+    MONTHS = {
+      'JAN' => '1', 'FEB' => '2', 'MAR' => '3', 'APR' => '4',
+      'MAY' => '5', 'JUN' => '6', 'JUL' => '7', 'AUG' => '8',
+      'SEP' => '9', 'OCT' => '10', 'NOV' => '11', 'DEC' => '12'
     }.freeze
 
     def initialize(cron_string)
@@ -69,7 +81,7 @@ def last(count = 1, period_end = Time.now, max_years = 5)
 
     def occurrences(period, count = nil, reverse: false)
       time_combinations = generate_time_combinations(period, reverse).lazy
-      wdays = parse_cron_part(:dows)
+      wdays = parse_cron_part(:wdays)
 
       time_combinations.each_with_object([]) do |(year, month, day, hour, minute), occ|
         break occ if count && occ.length == count
@@ -94,8 +106,8 @@ def split_cron_string
         minutes: splitted[0],
         hours: splitted[1],
         days: splitted[2],
-        months: splitted[3],
-        dows: splitted[4]
+        months: normalize_with(splitted[3], MONTHS),
+        wdays: normalize_with(splitted[4], WDAYS)
       }
     end
 
@@ -123,9 +135,13 @@ def parse_cron_part(time_unit)
     end
     # rubocop:enable Metrics
 
+    def normalize_with(string, mapping)
+      mapping.inject(string) { |str, (k, v)| str.gsub(k, v) }
+    end
+
     def cron_string_valid?
       # rubocop:disable Layout/LineLength
-      regex = %r{\A(\*|([0-5]?\d)(,([0-5]?\d))*|(\*/\d+)|(\d+-\d+)) (\*|([01]?\d|2[0-3])(,([01]?\d|2[0-3]))*|(\*/\d+)|(\d+-\d+)) (\*|([12]?\d|3[01])(,([12]?\d|3[01]))*|(\*/\d+)|(\d+-\d+)) (\*|([1-9]|1[0-2])(,([1-9]|1[0-2]))*|(\*/\d+)|(\d+-\d+)) (\*|([0-6])(,([0-6]))*|(\*/[0-6]+)|([0-6]-[0-6]))\z}
+      regex = %r{\A(\*|([0-5]?\d)(,([0-5]?\d))*|(\*/\d+)|(\d+-\d+)) (\*|([01]?\d|2[0-3])(,([01]?\d|2[0-3]))*|(\*/\d+)|(\d+-\d+)) (\*|([12]?\d|3[01])(,([12]?\d|3[01]))*|(\*/\d+)|(\d+-\d+)) (\*|(JAN|FEB|MAR|APR|MAY|JUN|JUL|AUG|SEP|OCT|NOV|DEC|[1-9]|1[0-2])(,(JAN|FEB|MAR|APR|MAY|JUN|JUL|AUG|SEP|OCT|NOV|DEC|[1-9]|1[0-2])|-(JAN|FEB|MAR|APR|MAY|JUN|JUL|AUG|SEP|OCT|NOV|DEC))*|(\*/\d+)|(\d+-\d+)) (\*|(SUN|MON|TUE|WED|THU|FRI|SAT|[0-6])(,(SUN|MON|TUE|WED|THU|FRI|SAT|[0-6])|-(SUN|MON|TUE|WED|THU|FRI|SAT))*|(\*/[0-6]+)|([0-6]-[0-6]))\z}
       # rubocop:enable Layout/LineLength
       cron_string.match?(regex)
     end

spec/cron_calc_spec.rb

@@ -132,7 +132,7 @@
       end
     end
 
-    context 'when DOW excludes days of month' do
+    context 'when wdays excludes days of month' do
       let(:cron_string) { '5 5 14-22 * 0,6' }
       let(:period) { Time.new(2024, 1, 1, 0, 0)..Time.new(2024, 2, 1, 0, 0) }
 
@@ -144,6 +144,32 @@
                               ])
       end
     end
+
+    context 'when named months are used' do
+      let(:cron_string) { '5 5 5 JAN,FEB *' }
+      let(:period) { Time.new(2024, 1, 1, 0, 0)..Time.new(2024, 3, 31, 0, 0) }
+
+      it do
+        expect(subject).to eq([
+                                Time.new(2024, 1, 5, 5, 5),
+                                Time.new(2024, 2, 5, 5, 5)
+                              ])
+      end
+    end
+
+    context 'when named wdays are used' do
+      let(:cron_string) { '5 5 1-8 FEB TUE-THU' }
+      let(:period) { Time.new(2024, 1, 1, 0, 0)..Time.new(2024, 3, 31, 0, 0) }
+
+      it do
+        expect(subject).to eq([
+                                Time.new(2024, 2, 1, 5, 5),
+                                Time.new(2024, 2, 6, 5, 5),
+                                Time.new(2024, 2, 7, 5, 5),
+                                Time.new(2024, 2, 8, 5, 5)
+                              ])
+      end
+    end
   end
 
   describe '#next' do