Enable using day aliases

Cargo.toml

@@ -8,4 +8,5 @@ edition = "2018"
 
 [dependencies]
 nom="^4"
-linked_hash_set="^0.1.4"
+linked_hash_set="^0.1.4"
+lazy_static = "1.4.0"

README.md

@@ -40,7 +40,7 @@ croon consists of two main parts:
 - CLI entry point
 - Library to parse cron expressions
 
-It has two external dependencies for development convenience: `nom` and `linked_hash_set`.
+It has two external dependencies for development convenience: `nom`, `linked_hash_set` and `lazy_static`.
 
 ### How it works
 

src/lib.rs

@@ -1,3 +1,6 @@
+#[macro_use]
+extern crate lazy_static;
+
 pub mod cron_table;
 mod error;
 mod expression;

src/parser.rs

@@ -1,3 +1,5 @@
+use std::collections::HashMap;
+
 use nom::{types::CompleteStr, *};
 
 use crate::{
@@ -17,28 +19,57 @@ impl Parser {
     }
 }
 
+lazy_static! {
+    static ref ALIAS_MAP: HashMap<&'static str, u32> = {
+        let mut m = HashMap::new();
+        m.insert("MON", 1);
+        m.insert("TUE", 2);
+        m.insert("WED", 3);
+        m.insert("THU", 4);
+        m.insert("FRI", 5);
+        m.insert("SAT", 6);
+        m.insert("SUN", 0);
+        m
+    };
+}
+
 named!(
   number<CompleteStr, u32>,
   map_res!(ws!(digit), |x: CompleteStr| x.0.parse())
 );
 
 named!(
   exact<CompleteStr, CronBaseExpression>,
-  do_parse!(n: number >> (CronBaseExpression::Exact(n)))
+  do_parse!(n: alt!(number | day) >> (CronBaseExpression::Exact(n)))
+);
+
+fn map_alias_to_number(alias: String) -> Result<u32, Error> {
+    if let Some(value) = ALIAS_MAP.get(&*alias) {
+        Ok(value.clone())
+    } else {
+        Err(Error)
+    }
+}
+
+named!(
+    day<CompleteStr, u32>,
+    do_parse!(
+        day: alt!(tag!("MON") | tag!("TUE") | tag!("WED") | tag!("THU") | tag!("FRI") | tag!("SAT") | tag!("SUN")) >> (map_alias_to_number(day.0.to_string()).unwrap())
+    )
 );
 
 named!(
   range<CompleteStr, CronBaseExpression>,
   complete!(do_parse!(
-      start: number >> tag!("-") >> end: number >> (CronBaseExpression::Range(start, end))
+      start: alt!(number | day) >> tag!("-") >> end: alt!(number| day) >> (CronBaseExpression::Range(start, end))
   ))
 );
 
 named!(all<CompleteStr, CronBaseExpression>, do_parse!(tag!("*") >> (CronBaseExpression::All)));
 
 named!(
   cron_base_expression<CompleteStr, CronBaseExpression>,
-  alt!(all | range | exact)
+  alt!(all | range | exact )
 );
 
 named!(
@@ -65,7 +96,7 @@ named!(
     command<CompleteStr, String>,
     do_parse!(
         multispace0 >>
-        command: take_while!(|c: char| c.is_alphanumeric() || c == '/' || c.is_whitespace()) >> (String::from(command.0))
+        command: take_while!(|c: char| c.is_alphanumeric() || c == '\'' || c == '/' || c.is_whitespace()) >> (String::from(command.0))
     )
 );
 
@@ -101,11 +132,26 @@ mod test {
         assert!(number(CompleteStr("AAA")).is_err());
     }
 
+    #[test]
+    fn test_valid_day() {
+        day(CompleteStr("MON")).unwrap();
+    }
+
+    #[test]
+    fn test_invalid_alias() {
+        assert!(day(CompleteStr("MoN")).is_err());
+    }
+
     #[test]
     fn test_valid_range() {
         range(CompleteStr("2-4")).unwrap();
     }
 
+    #[test]
+    fn test_valid_range_of_number_and_day() {
+        range(CompleteStr("MON-4")).unwrap();
+    }
+
     #[test]
     fn test_invalid_range() {
         assert!(range(CompleteStr("2-A")).is_err());
@@ -141,6 +187,11 @@ mod test {
         cron_expression_list(CompleteStr("4,2")).unwrap();
     }
 
+    #[test]
+    fn test_valid_alias_list() {
+        cron_expression_list(CompleteStr("MON,2")).unwrap();
+    }
+
     #[test]
     fn test_invalid_number_list() {
         assert!(cron_expression_list(CompleteStr("A,4,2")).is_err());