Switch from enum_dispatch to a custom macro

src/main.rs

@@ -1,9 +1,10 @@
+use std::fmt::Display;
+
 use clap::{Parser, Subcommand};
-use enum_dispatch::enum_dispatch;
 
 mod one;
 
-#[derive(Parser)]
+#[derive(Parser, Default)]
 struct GlobalArgs {}
 
 #[derive(Parser)]
@@ -14,16 +15,42 @@ struct Args {
     global: GlobalArgs,
 }
 
-#[enum_dispatch]
 trait Problem {
-    fn solve(self, args: GlobalArgs) -> color_eyre::Result<()>;
+    type Solution: Display;
+
+    fn solve(self, args: GlobalArgs) -> color_eyre::Result<Self::Solution>;
 }
 
-#[derive(Subcommand)]
-#[enum_dispatch(Problem)]
-enum Problems {
-    #[clap(name = "1")]
-    One(one::Args),
+macro_rules! problems {
+    ($($module:ident = $alias:tt),* $(,)?) => {
+        paste::paste! {
+            #[derive(Subcommand)]
+            enum Problems {
+            $(
+                #[clap(name = stringify!($alias))]
+                [<$module:camel>]($module::Args),
+            )*
+            }
+
+            impl Problems {
+                pub fn solve(self, args: GlobalArgs) -> color_eyre::Result<()> {
+                    match self {
+                    $(
+                        Self::[<$module:camel>](i) => {
+                            println!("Solution: {}", i.solve(args)?);
+                        }
+                    )*
+                    }
+                    Ok(())
+                }
+            }
+        }
+    };
+}
+
+problems! {
+    one = 1,
+    two = 2,
 }
 
 fn main() -> color_eyre::Result<()> {