Merge pull request #4 from n0-computer/Frando/Err-macro

feat: add Err macro

Author: Frando

examples/simple.rs

@@ -1,6 +1,6 @@
 use std::io;
 
-use n0_error::{StackError, e, meta};
+use n0_error::{Err, StackError, e, meta};
 
 use self::error::CopyError;
 use crate::error::{InvalidArgsError, OperationError};
@@ -27,6 +27,11 @@ fn main() {
     print(err);
 }
 
+fn _some_fn() -> Result<(), CopyError> {
+    // Err! macro works like e! but wraps in Err
+    Err!(CopyError::Read, io::Error::other("yada"))
+}
+
 fn operation() -> Result<(), OperationError> {
     let res = copy();
     res?;
@@ -67,13 +72,6 @@ pub mod error {
         Copy { source: CopyError },
     }
 
-    #[macro_export]
-    macro_rules! CopyError {
-        ($variant:ident { $($rest:tt)* }) => {
-            e!(CopyError::$variant { $($rest)* })
-        };
-    }
-
     #[n0_error::add_meta]
     #[derive(n0_error::Error)]
     pub enum CopyError {

src/macros.rs

@@ -21,6 +21,16 @@ macro_rules! e {
     };
 }
 
+/// Constructs an error enum/struct value and wraps it in `Err(err)`.
+///
+/// See [`e`] for supported syntax.
+#[macro_export]
+macro_rules! Err {
+    ($($tt:tt)*) => {
+        Err(e!($($tt)*))
+    }
+}
+
 /// Propagates an error, adding formatted context.
 ///
 /// - `whatever!("msg")` returns `Err(format_err!(...))`.