Slightly nicer day parsing.

2016/src/main.rs

@@ -14,16 +14,19 @@ pub mod day16;
 pub mod day23;
 pub mod day24;
 
-fn get_impl(day: i32) -> Box<common::Solution> {
-    match day {
-        1 => { Box::new(day1::Day1::new()) }
-        12 => { Box::new(day12::Day12::new()) }
-        15 => { Box::new(day15::Day15::new()) }
-        16 => { Box::new(day16::Day16::new()) }
-        23 => { Box::new(day23::Day23::new()) }
-        24 => { Box::new(day24::Day24::new()) }
-        _ => {
-            panic!("Unimplemented day {}", day)
+fn get_impl(day: &str) -> Box<common::Solution> {
+    match day.parse() {
+        Ok(1) => { Box::new(day1::Day1::new()) }
+        Ok(12) => { Box::new(day12::Day12::new()) }
+        Ok(15) => { Box::new(day15::Day15::new()) }
+        Ok(16) => { Box::new(day16::Day16::new()) }
+        Ok(23) => { Box::new(day23::Day23::new()) }
+        Ok(24) => { Box::new(day24::Day24::new()) }
+        Ok(val) => {
+            panic!("Unimplemented day {}", val)
+        },
+        Err(_) => {
+            panic!("Invalid day");
         }
     }
 }
@@ -48,9 +51,7 @@ fn main() {
              .takes_value(true))
         .get_matches();
 
-    let day: i32 = (&matches.value_of("day").unwrap()).parse()
-        .expect("Invalid int");
-    let mut implementation = get_impl(day);
+    let mut implementation = get_impl(&matches.value_of("day").unwrap());
     let mut data: Box<io::Read> = match matches.value_of("input") {
         Some(filename) => { Box::new(fs::File::open(filename).unwrap()) }
         None => { Box::new(io::stdin()) }
@@ -72,7 +73,7 @@ mod tests {
         // Verify that we can load all days
         let last_implemented = 1;
         for d in 1..(last_implemented + 1) {
-            get_impl(d);
+            get_impl(&format!("{}", d));
         }
     }
 }