diff --git a/hbasm/src/lib.rs b/hbasm/src/lib.rs
index c73feff..6c9125f 100644
--- a/hbasm/src/lib.rs
+++ b/hbasm/src/lib.rs
@@ -1,3 +1,4 @@
+use std::fmt::{Display, Formatter};
 use {
     logos::{Lexer, Logos, Span},
     std::{ops::Range, str::FromStr},
@@ -58,6 +59,14 @@ pub struct Error {
     span: Span,
 }
 
+impl Display for Error {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        write!(f, "Error {:?} at {:?}", self.kind, self.span)
+    }
+}
+
+impl std::error::Error for Error {}
+
 macro_rules! expect_matches {
     ($self:expr, $($pat:pat),* $(,)?) => {$(
         let $pat = $self.next()?
diff --git a/hbasm/src/main.rs b/hbasm/src/main.rs
index 171cfe2..bdb6a7a 100644
--- a/hbasm/src/main.rs
+++ b/hbasm/src/main.rs
@@ -1,3 +1,14 @@
-fn main() {
-    // TODO
+use std::{
+    error::Error,
+    io::{stdin, stdout, Read, Write},
+};
+
+fn main() -> Result<(), Box<dyn Error>> {
+    let mut code = String::new();
+    stdin().read_to_string(&mut code)?;
+
+    let mut buf = vec![];
+    hbasm::assembly(&code, &mut buf)?;
+    stdout().write_all(&buf)?;
+    Ok(())
 }