added list len, front, and back

src/sym.rs

@@ -145,14 +145,15 @@ impl Args {
                 } else {
                     return Err("expected no args".to_string());
                 }
-            }
+            },
+
             Args::Infinite => {
                 if !args.is_empty() {
                     return Ok(());
                 } else {
                     return Err("expected args but none were provided".to_string());
                 }
-            }
+            },
 
             Args::Lazy(ref num) => {
                 let called_arg_count = args.len();
@@ -167,7 +168,7 @@ impl Args {
                 } else if let Ctr::None = *args.car {
                     return Err(format!("expected {} args. Got 0.", num,));
                 }
-            }
+            },
 
             Args::Strict(ref arg_types) => {
                 let mut idx: usize = 0;
@@ -202,7 +203,7 @@ impl Args {
                         return Err("too few arguments".to_string());
                     }
                 }
-            }
+            },
         }
 
         Ok(())