From db19a553c716f4e8f311f7f40d331d2ff82f6624 Mon Sep 17 00:00:00 2001
From: William Venner <william@venner.io>
Date: Sat, 22 Jan 2022 19:12:47 +0000
Subject: [PATCH] Add DisplayLuaError trait for specialized error messages

---
 gmod/src/lua/returns.rs | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/gmod/src/lua/returns.rs b/gmod/src/lua/returns.rs
index 8bfed8c..f211052 100644
--- a/gmod/src/lua/returns.rs
+++ b/gmod/src/lua/returns.rs
@@ -1,4 +1,4 @@
-use std::num::NonZeroI32;
+use std::{num::NonZeroI32, borrow::Cow};
 
 #[repr(transparent)]
 pub struct ValuesReturned(pub i32);
@@ -44,12 +44,21 @@ impl From<Option<NonZeroI32>> for ValuesReturned {
 	}
 }
 
-impl<E: std::fmt::Debug> From<Result<i32, E>> for ValuesReturned {
+pub trait DisplayLuaError {
+	fn display_lua_error<'a>(&'a self) -> Cow<'a, str>;
+}
+impl<E: std::fmt::Debug> DisplayLuaError for E {
+	#[inline(always)]
+	fn display_lua_error<'a>(&'a self) -> Cow<'a, str> {
+		Cow::Owned(format!("{:?}", self))
+	}
+}
+impl<E: DisplayLuaError> From<Result<i32, E>> for ValuesReturned {
 	#[inline(always)]
 	fn from(res: Result<i32, E>) -> ValuesReturned {
 		match res {
 			Ok(vals) => ValuesReturned(vals),
-			Err(err) => unsafe { super::state().error(&format!("{:?}", err)) }
+			Err(err) => unsafe { super::state().error(err.display_lua_error().as_ref()) }
 		}
 	}
 }
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