Add commas and dots

src/lexer.rs

         Matcher::new(r#"^[a-z][a-zA-Z_\-]*"#, TokenType::Identfiier),
         Matcher::new(r#"^[0-9]+"#, TokenType::Number),
         Matcher::new(r#"^\*"#, TokenType::Star),
+        Matcher::new(r#"^,"#, TokenType::Comma),
+        Matcher::new(r#"^\."#, TokenType::Dot),
     ];
 }
 
         assert_eq!(scan("*").unwrap(), vec![Token::new(TokenType::Star, "*")])
     }
 
+    #[test]
+    fn it_scans_a_comma() {
+        assert_eq!(scan(",").unwrap(), vec![Token::new(TokenType::Comma, ",")])
+    }
+
+    #[test]
+    fn it_scans_a_dot() {
+        assert_eq!(scan(".").unwrap(), vec![Token::new(TokenType::Dot, ".")])
+    }
+
     #[test]
     fn it_scans_a_whole_expression() {
         assert_eq!(

src/token.rs

 
 #[derive(Clone, Copy, Debug, PartialEq)]
 pub enum TokenType {
+    Comma,
+    Dot,
     From,
     Identfiier,
     Number,
             f,
             "{}",
             match self {
+                TokenType::Comma => "Comma",
+                TokenType::Dot => "Dot",
                 TokenType::Identfiier => "Identifier",
                 TokenType::Number => "Number",
                 TokenType::Star => "Star",