diff --git a/hblang/src/lib.rs b/hblang/src/lib.rs
index 44ed514..0538449 100644
--- a/hblang/src/lib.rs
+++ b/hblang/src/lib.rs
@@ -553,6 +553,63 @@ pub fn run_test(
     panic!("test failed");
 }
 
+#[derive(Default)]
+pub struct Options {
+    pub fmt:         bool,
+    pub fmt_current: bool,
+}
+
+pub fn run_compiler(
+    root_file: &str,
+    options: Options,
+    out: &mut impl std::io::Write,
+) -> io::Result<()> {
+    let parsed = parse_from_fs(1, root_file)?;
+
+    fn format_to_stdout(ast: parser::Ast) -> std::io::Result<()> {
+        let source = std::fs::read_to_string(&*ast.path)?;
+        parser::with_fmt_source(&source, || {
+            for expr in ast.exprs() {
+                use std::io::Write;
+                writeln!(std::io::stdout(), "{expr}")?;
+            }
+            std::io::Result::Ok(())
+        })
+    }
+
+    fn format_ast(ast: parser::Ast) -> std::io::Result<()> {
+        let source = std::fs::read_to_string(&*ast.path)?;
+        let mut output = Vec::new();
+        parser::with_fmt_source(&source, || {
+            for expr in ast.exprs() {
+                use std::io::Write;
+                writeln!(output, "{expr}")?;
+            }
+            std::io::Result::Ok(())
+        })?;
+
+        std::fs::write(&*ast.path, output)?;
+
+        Ok(())
+    }
+
+    if options.fmt {
+        for parsed in parsed {
+            format_ast(parsed)?;
+        }
+    } else if options.fmt_current {
+        format_to_stdout(parsed.into_iter().next().unwrap())?;
+    } else {
+        let mut codegen = codegen::Codegen::default();
+        codegen.files = parsed;
+
+        codegen.generate();
+        codegen.dump(out)?;
+    }
+
+    Ok(())
+}
+
 #[cfg(test)]
 mod test {
     use std::sync::Arc;
diff --git a/hblang/src/main.rs b/hblang/src/main.rs
index 3771633..d4f06bf 100644
--- a/hblang/src/main.rs
+++ b/hblang/src/main.rs
@@ -1,7 +1,6 @@
 fn main() -> std::io::Result<()> {
     let args = std::env::args().collect::<Vec<_>>();
     let args = args.iter().map(String::as_str).collect::<Vec<_>>();
-    let root = args.get(1).copied().unwrap_or("main.hb");
 
     if args.contains(&"--help") || args.contains(&"-h") {
         println!("Usage: hbc [OPTIONS...] <FILE>");
@@ -9,48 +8,12 @@ fn main() -> std::io::Result<()> {
         return Err(std::io::ErrorKind::Other.into());
     }
 
-    let parsed = hblang::parse_from_fs(1, root)?;
-
-    fn format_to_stdout(ast: hblang::parser::Ast) -> std::io::Result<()> {
-        let source = std::fs::read_to_string(&*ast.path)?;
-        hblang::parser::with_fmt_source(&source, || {
-            for expr in ast.exprs() {
-                use std::io::Write;
-                writeln!(std::io::stdout(), "{expr}")?;
-            }
-            std::io::Result::Ok(())
-        })
-    }
-
-    fn format_ast(ast: hblang::parser::Ast) -> std::io::Result<()> {
-        let source = std::fs::read_to_string(&*ast.path)?;
-        let mut output = Vec::new();
-        hblang::parser::with_fmt_source(&source, || {
-            for expr in ast.exprs() {
-                use std::io::Write;
-                writeln!(output, "{expr}")?;
-            }
-            std::io::Result::Ok(())
-        })?;
-
-        std::fs::write(&*ast.path, output)?;
-
-        Ok(())
-    }
-
-    if args.contains(&"--fmt") {
-        for parsed in parsed {
-            format_ast(parsed)?;
-        }
-    } else if args.contains(&"--fmt-current") {
-        format_to_stdout(parsed.into_iter().next().unwrap())?;
-    } else {
-        let mut codegen = hblang::codegen::Codegen::default();
-        codegen.files = parsed;
-
-        codegen.generate();
-        codegen.dump(&mut std::io::stdout())?;
-    }
-
-    Ok(())
+    hblang::run_compiler(
+        args.get(1).copied().unwrap_or("main.hb"),
+        hblang::Options {
+            fmt:         args.contains(&"--fmt"),
+            fmt_current: args.contains(&"--fmt-current"),
+        },
+        &mut std::io::stdout(),
+    )
 }