feat: return option from solution parts

this allows to print _not solved_ for solution parts that haven't been solved yet.

adjust `solve` macro to handle one solution part rather than both.
this allows for easier debugging of real input.

src/bin/scaffold.rs

@@ -4,16 +4,18 @@ use std::{
     process,
 };
 
-const MODULE_TEMPLATE: &str = r###"pub fn part_one(input: &str) -> u32 {
-    0
+const MODULE_TEMPLATE: &str = r###"pub fn part_one(input: &str) -> Option<u32> {
+    None
 }
 
-pub fn part_two(input: &str) -> u32 {
-    0
+pub fn part_two(input: &str) -> Option<u32> {
+    None
 }
 
 fn main() {
-    aoc::solve!(&aoc::read_file("inputs", DAY), part_one, part_two)
+    let input = &aoc::read_file("inputs", DAY);
+    aoc::solve!(1, part_one, input);
+    aoc::solve!(2, part_two, input);
 }
 
 #[cfg(test)]
@@ -24,14 +26,14 @@ mod tests {
     fn test_part_one() {
         use aoc::read_file;
         let input = read_file("examples", DAY);
-        assert_eq!(part_one(&input), 0);
+        assert_eq!(part_one(&input), None);
     }
 
     #[test]
     fn test_part_two() {
         use aoc::read_file;
         let input = read_file("examples", DAY);
-        assert_eq!(part_two(&input), 0);
+        assert_eq!(part_two(&input), None);
     }
 }
 "###;

src/lib.rs

@@ -11,28 +11,30 @@ pub const ANSI_RESET: &str = "\x1b[0m";
 
 #[macro_export]
 macro_rules! solve {
-    ($input:expr, $part_one:ident, $part_two:ident) => {{
+    ($part:expr, $solver:ident, $input:expr) => {{
         use aoc::{ANSI_BOLD, ANSI_ITALIC, ANSI_RESET};
         use std::fmt::Display;
         use std::time::Instant;
 
-        fn print_result<T: Display>(func: impl FnOnce(&str) -> T, input: &str) {
+        fn print_result<T: Display>(func: impl FnOnce(&str) -> Option<T>, input: &str) {
             let timer = Instant::now();
             let result = func(input);
             let elapsed = timer.elapsed();
-            println!(
-                "{} {}(elapsed: {:.2?}){}",
-                result, ANSI_ITALIC, elapsed, ANSI_RESET
-            );
+            match result {
+                Some(result) => {
+                    println!(
+                        "{} {}(elapsed: {:.2?}){}",
+                        result, ANSI_ITALIC, elapsed, ANSI_RESET
+                    );
+                },
+                None => {
+                    println!("not solved.")
+                }
+            }
         }
 
-        println!("🎄 {}Part 1{} 🎄", ANSI_BOLD, ANSI_RESET);
-        println!("");
-        print_result($part_one, $input);
-        println!("");
-        println!("🎄 {}Part 2{} 🎄", ANSI_BOLD, ANSI_RESET);
-        println!("");
-        print_result($part_two, $input);
+        println!("🎄 {}Part {}{} 🎄", ANSI_BOLD, $part, ANSI_RESET);
+        print_result($solver, $input);
     }};
 }
 

src/main.rs

@@ -18,7 +18,7 @@ fn main() {
             let output = String::from_utf8(cmd.stdout).unwrap();
             let is_empty = output.is_empty();
 
-            println!("{}", if is_empty { "Not solved." } else { &output });
+            println!("{}", if is_empty { "Not solved." } else { &output.trim() });
 
             if is_empty {
                 0_f64