Function cron_parser::parse_field

pub fn parse_field(
    field: &str, 
    min: u32, 
    max: u32
) -> Result<BTreeSet<u32>, ParseError>

parse_field Allowed special characters:

• * any value
• , value list separator
• - range of values
• / step values

minutes min: 0, max: 59
hours   min: 0, max: 23
days    min: 1, max: 31
month   min: 1, max: 12
dow     min: 0, max: 6 or min: Sun, max Sat

Day of week (dow):
   Sun = 0
   Mon = 1
   Tue = 2
   Wed = 3
   Thu = 4
   Fri = 5
   Sat = 6

The field column can have a * or a list of elements separated by commas. An element is either a number in the ranges or two numbers in the range separated by a hyphen, slashes can be combined with ranges to specify step values

Example

use cron_parser::parse_field;
use std::collections::BTreeSet;

fn main() {
     // every 3 months
     assert_eq!(parse_field("*/3", 1, 12).unwrap(),
     BTreeSet::<u32>::from([1,4,7,10].iter().cloned().collect()));

     // day 31
     assert_eq!(parse_field("31", 1, 31).unwrap(),
     BTreeSet::<u32>::from([31].iter().cloned().collect()));

     // every minute from 40 through 50
     assert_eq!(parse_field("40-50", 0, 59).unwrap(),
     BTreeSet::<u32>::from([40,41,42,43,44,45,46,47,48,49,50].iter().cloned().collect()));

     // at hour 3,15,23
     assert_eq!(parse_field("15,3,23", 0, 23).unwrap(),
     BTreeSet::<u32>::from([3,15,23].iter().cloned().collect()));
}