fixed convenience scheduling (#47)

* Update README.md

Added missing stream insertion operator to example.   Also, header files for chrono and thread as well as a missing namespace for literals added.

---------

Co-authored-by: Per Malmberg <PerMalmberg@users.noreply.github.com>

README.md

@@ -6,10 +6,16 @@ A C++ scheduling library using cron formatting.
 Libcron offers an easy to use API to add callbacks with corresponding cron-formatted strings:
 
 ```
+#include <libcron/Cron.h>
+#include <libcron/CronData.h>
+#include <chrono>
+#include <thread>
+using namespace std::chrono_literals;
+
 libcron::Cron cron;
 
 cron.add_schedule("Hello from Cron", "* * * * * ?", [=](auto&) {
-	std::cout << "Hello from libcron!" std::endl;
+	std::cout << "Hello from libcron!" << std::endl;
 });
 ```
 
@@ -19,7 +25,7 @@ To trigger the execution of callbacks, one must call `libcron::Cron::tick` at le
 while(true)
 {
 	cron.tick();
-	std::this_thread::sleep_for(500mS);
+	std::this_thread::sleep_for(500ms);
 }
 ```
 
@@ -188,23 +194,28 @@ the '?'-character to ensure that it is not possible to specify a statement which
 |Expression | Meaning
 | --- | --- |
 | * * * * * ? | Every second
+| 0 * * * * ? | Every minute
 | 0 0 12 * * MON-FRI | Every Weekday at noon
 | 0 0 12 1/2 * ?	| Every 2 days, starting on the 1st at noon
 | 0 0 */12 ? * * | Every twelve hours
 | @hourly | Every hour
 
+Note that the expression formatting has a part for seconds and the day of week. 
+For the day of week part, a question mark ? is utilized. This format
+may not be parsed by all online crontab calculators or expression generators.
+
 ## Convenience scheduling
 
 These special time specification tokens which replace the 5 initial time and date fields, and are prefixed with the '@' character, are supported:
 
 |Token|Meaning
 | --- | --- |
-| @yearly | Run once a year, ie.  "0 0 1 1 *".
+| @yearly | Run once a year, ie.  "0 0 0 1 1 *".
-| @annually | Run once a year, ie.  "0 0 1 1 *".
+| @annually | Run once a year, ie.  "0 0 0 1 1 *"".
-| @monthly | Run once a month, ie. "0 0 1 * *".
+| @monthly | Run once a month, ie. "0 0 0 1 * *".
-| @weekly | Run once a week, ie.  "0 0 * * 0".
+| @weekly | Run once a week, ie.  "0 0 0 * * 0".
-| @daily | Run once a day, ie.   "0 0 * * *".
+| @daily | Run once a day, ie.   "0 0 0 * * ?".
-| @hourly | Run once an hour, ie. "0 * * * *".
+| @hourly | Run once an hour, ie. "0 0 * * * ?".
 	
 # Randomization
 

libcron/src/CronData.cpp

@@ -39,12 +39,12 @@ namespace libcron
     {
         // First, check for "convenience scheduling" using @yearly, @annually,
         // @monthly, @weekly, @daily or @hourly.
-        std::string tmp = std::regex_replace(cron_expression, std::regex("@yearly"), "0 0 1 1 *");
+        std::string tmp = std::regex_replace(cron_expression, std::regex("@yearly"), "0 0 0 1 1 *");
-        tmp = std::regex_replace(tmp, std::regex("@annually"), "0 0 1 1 *");
+        tmp = std::regex_replace(tmp, std::regex("@annually"), "0 0 0 1 1 *");
-        tmp = std::regex_replace(tmp, std::regex("@monthly"), "0 0 1 * *");
+        tmp = std::regex_replace(tmp, std::regex("@monthly"), "0 0 0 1 * *");
-        tmp = std::regex_replace(tmp, std::regex("@weekly"), "0 0 * * 0");
+        tmp = std::regex_replace(tmp, std::regex("@weekly"), "0 0 0 * * 0");
-        tmp = std::regex_replace(tmp, std::regex("@daily"), "0 0 * * *");
+        tmp = std::regex_replace(tmp, std::regex("@daily"), "0 0 0 * * ?");
-        const std::string expression = std::regex_replace(tmp, std::regex("@hourly"), "0 * * * *");
+        const std::string expression = std::regex_replace(tmp, std::regex("@hourly"), "0 0 * * * ?");
 
         // Second, split on white-space. We expect six parts.
         std::regex split{ R"#(^\s*(.*?)\s+(.*?)\s+(.*?)\s+(.*?)\s+(.*?)\s+(.*?)\s*$)#",

test/CronDataTest.cpp

@@ -237,4 +237,13 @@ SCENARIO("Replacing text with numbers")
         std::string s = "JAN-DEC";
         REQUIRE(CronData::replace_string_name_with_numeric<libcron::Months>(s) == "1-12");
     }
+}
+
+SCENARIO("Parsing @ expressions works") {
+    REQUIRE(CronData::create("@yearly").is_valid());
+    REQUIRE(CronData::create("@annually").is_valid());
+    REQUIRE(CronData::create("@monthly").is_valid());
+    REQUIRE(CronData::create("@weekly").is_valid());
+    REQUIRE(CronData::create("@daily").is_valid());
+    REQUIRE(CronData::create("@hourly").is_valid());
 }

test/CronScheduleTest.cpp

@@ -184,6 +184,15 @@ SCENARIO("Examples from README.md")
                          DT(2018_y / 03 / 1, hours{12}, minutes{13}, seconds{48})
                  }));
 
+    REQUIRE(test("0 * * * * ?", DT(2018_y / 03 / 1, hours{ 12 }, minutes{ 0 }, seconds{ 10 }),
+        {
+                DT(2018_y / 03 / 1, hours{12}, minutes{1}, seconds{0}),
+                DT(2018_y / 03 / 1, hours{12}, minutes{2}, seconds{0}),
+                DT(2018_y / 03 / 1, hours{12}, minutes{3}, seconds{0}),
+                DT(2018_y / 03 / 1, hours{12}, minutes{4}, seconds{0})
+        }));
+
+
     REQUIRE(test("0 0 12 * * MON-FRI", DT(2018_y / 03 / 10, hours{12}, minutes{13}, seconds{45}),
                  {
                          DT(2018_y / 03 / 12, hours{12}),
@@ -212,4 +221,4 @@ SCENARIO("Examples from README.md")
 SCENARIO("Unable to calculate time point")
 {
     REQUIRE_FALSE(test( "0 0 * 31 FEB *", DT(2021_y / 1 / 1), DT(2022_y / 1 / 1)));
-}
+}