diff --git a/Cargo.toml b/Cargo.toml
index 40a9121..f372dd0 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "rematch"
-version = "0.3.0"
+version = "0.3.1"
 authors = ["Avril <flanchan@cumallover.me>"]
 edition = "2024"
 
diff --git a/src/main.rs b/src/main.rs
index 3fccdf6..ec25428 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -3,6 +3,52 @@
 mod re;
 mod text;
 
+/// Run an expression on an named value with a result type `Result<T, U>`.
+/// Where `T` and `U` have *the same API surface* for the duration of the provided expression.
+///
+/// # Example
+/// If there is a value `let mut value: Result<T, U>`, where `T: Write` & `U: BufWrite`;
+/// the expression `value.flush()` is valid for both `T` and `U`.
+/// Therefore, it can be simplified to be called as so: `unwrap_either(mut value => value.flush())`.
+///
+/// # Reference capture vs. `move` capture.
+/// Note that by default, the identified value is **moved** *into* the expression.
+/// The type of reference can be controlled by appending `ref`, `mut`, or `ref mut` to the ident.
+///
+/// Identifier capture table:
+/// - **none** ~default~ - Capture by move, value is immutable in expression.
+/// - `mut` - Capture by move, value is mutable in expression.
+/// - `ref` - Capture by ref, value is immutable (`&value`) in expression.
+/// - `ref mut` - Capture by mutable ref, value is mutable (`&mut value`) in expression. (__NOTE__: `value` must be defined as mutable to take a mutable reference of it.)
+///
+/// Essentially the same rules as any `match` branch pattern.
+macro_rules! unwrap_either {
+    ($res:ident => $($rest:tt)+) => {
+        match $res {
+	    Ok(ref mut $res) => $($rest)+,
+	    Err(ref mut $res) => $($rest)+,
+	}
+    };
+    (ref mut $res:ident => $($rest:tt)+) => {
+        match $res {
+	    Ok(ref mut $res) => $($rest)+,
+	    Err(ref mut $res) => $($rest)+,
+	}
+    };
+    (ref $res:ident => $($rest:tt)+) => {
+        match $res {
+	    Ok(ref $res) => $($rest)+,
+	    Err(ref $res) => $($rest)+,
+	}
+    };
+    (mut $res:ident => $($rest:tt)+) => {
+        match $res {
+	    Ok(mut $res) => $($rest)+,
+	    Err(mut $res) => $($rest)+,
+	}
+    };
+}
+
 use color_eyre::{
     eyre::{
         self,
@@ -99,9 +145,9 @@ fn main() -> eyre::Result<()>
 	use std::io::Write;
 	let mut stdout = std::io::stdout();
 	
-	if &text[..] == "-" {
+	let stdout = if &text[..] == "-" {
+	    let mut stdout = std::io::BufWriter::new(stdout.lock());
 	    text::stdin_lines(|text| -> eyre::Result<bool> {
-		let mut stdout = stdout.lock();
 		match re.exec(&text)? {
 		    Some(g) /*if g.len() > group*/ => // NOTE: This check branch has now been moved into `print_groups()`
 			print_groups(&mut stdout, &g, &groups)?, //println!("{}", &g[group]),
@@ -109,14 +155,18 @@ fn main() -> eyre::Result<()>
 		}
 		Ok(true)
 	    })?;
+
+            Some(stdout)
 	} else {
 
 	    match re.exec(&text)? {
 		Some(g) /*if g.len() > group*/ => print_groups(&mut stdout, &g[..], &groups)?,//println!("{}", &g.nth(group).unwrap().map(|x| x.as_ref()).unwrap_or("")),
 		_ => (),
 	    }
-	}
-	stdout.flush().unwrap();
+
+            None
+	}.ok_or_else(move || stdout);
+	unwrap_either!(mut stdout => stdout.flush()).unwrap();
     }
     Ok(())
 }