From 8004d6ee68bb0158f3e02568fdd697a3ab6ec1ae Mon Sep 17 00:00:00 2001
From: Quentin Boyer <quentin+dev@familleboyer.net>
Date: Wed, 27 Nov 2024 12:25:31 +0100
Subject: [PATCH] Switch from enum_dispatch to a custom macro

---
 Cargo.lock  | 20 +++++++-------------
 Cargo.toml  |  2 +-
 src/main.rs | 45 ++++++++++++++++++++++++++++++++++++---------
 3 files changed, 44 insertions(+), 23 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index c3dd9f9..8759325 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -169,25 +169,13 @@ version = "1.0.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5b63caa9aa9397e2d9480a9b13673856c78d8ac123288526c37d7839f2a86990"
 
-[[package]]
-name = "enum_dispatch"
-version = "0.3.13"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "aa18ce2bc66555b3218614519ac839ddb759a7d6720732f979ef8d13be147ecd"
-dependencies = [
- "once_cell",
- "proc-macro2",
- "quote",
- "syn",
-]
-
 [[package]]
 name = "euler"
 version = "0.1.0"
 dependencies = [
  "clap",
  "color-eyre",
- "enum_dispatch",
+ "paste",
 ]
 
 [[package]]
@@ -272,6 +260,12 @@ version = "3.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c1b04fb49957986fdce4d6ee7a65027d55d4b6d2265e5848bbb507b58ccfdb6f"
 
+[[package]]
+name = "paste"
+version = "1.0.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "57c0d7b74b563b49d38dae00a0c37d4d6de9b432382b2892f0574ddcae73fd0a"
+
 [[package]]
 name = "pin-project-lite"
 version = "0.2.15"
diff --git a/Cargo.toml b/Cargo.toml
index ccc1bbc..84a0d79 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -7,4 +7,4 @@ edition = "2021"
 [dependencies]
 clap = { version = "4.5.21", features = ["derive"] }
 color-eyre = "0.6.3"
-enum_dispatch = "0.3.13"
+paste = "1.0.15"
diff --git a/src/main.rs b/src/main.rs
index 516a33f..8214579 100644
--- a/src/main.rs
+++ b/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<()> {