From f683bba4004cc07f9ac91d5d99a6bab76f335dba Mon Sep 17 00:00:00 2001
From: Laurenz <laurmaedje@gmail.com>
Date: Sat, 30 Mar 2019 16:42:52 +0100
Subject: =?UTF-8?q?Create=20error=5Ftype!=20macro=20=E2=9C=94?=
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---
 src/error.rs | 38 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)
 create mode 100644 src/error.rs

(limited to 'src/error.rs')

diff --git a/src/error.rs b/src/error.rs
new file mode 100644
index 00000000..cfdb1f0e
--- /dev/null
+++ b/src/error.rs
@@ -0,0 +1,38 @@
+/// Create an error type.
+macro_rules! error_type {
+    (
+        $var:ident: $err:ident,
+        $(res: $res:ident,)*
+        show: $f:ident => $show:expr,
+        $(source: $source:expr,)*
+        $(from: ($from:path, $conv:expr),)*
+    ) => {
+        $(type $res<T> = std::result::Result<T, $err>;)*
+
+        impl std::fmt::Display for $err {
+            fn fmt(&self, $f: &mut std::fmt::Formatter) -> std::fmt::Result {
+                let $var = self;
+                $show
+            }
+        }
+
+        impl std::fmt::Debug for $err {
+            fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+                std::fmt::Display::fmt(self, f)
+            }
+        }
+
+        impl std::error::Error for $err {
+            $(fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
+                let $var = self;
+                $source
+            })*
+        }
+
+        $(impl From<$from> for $err {
+            fn from($var: $from) -> $err {
+                $conv
+            }
+        })*
+    };
+}
-- 
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