diff --git a/Cargo.lock b/Cargo.lock
index a98bc7d..e4434eb 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -36,12 +36,78 @@ dependencies = [
  "yansi",
 ]
 
+[[package]]
+name = "async-trait"
+version = "0.1.83"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "721cae7de5c34fbb2acd27e21e6d2cf7b886dce0c27388d46c4e6c47ea4318dd"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "autocfg"
 version = "1.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ace50bade8e6234aa140d9a2f552bbee1db4d353f69b8217bc503490fc1a9f26"
 
+[[package]]
+name = "axum"
+version = "0.7.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "edca88bc138befd0323b20752846e6587272d3b03b0343c8ea28a6f819e6e71f"
+dependencies = [
+ "async-trait",
+ "axum-core",
+ "bytes",
+ "futures-util",
+ "http",
+ "http-body",
+ "http-body-util",
+ "hyper",
+ "hyper-util",
+ "itoa",
+ "matchit",
+ "memchr",
+ "mime",
+ "percent-encoding",
+ "pin-project-lite",
+ "rustversion",
+ "serde",
+ "serde_json",
+ "serde_path_to_error",
+ "serde_urlencoded",
+ "sync_wrapper 1.0.2",
+ "tokio",
+ "tower",
+ "tower-layer",
+ "tower-service",
+ "tracing",
+]
+
+[[package]]
+name = "axum-core"
+version = "0.4.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "09f2bd6146b97ae3359fa0cc6d6b376d9539582c7b4220f041a33ec24c226199"
+dependencies = [
+ "async-trait",
+ "bytes",
+ "futures-util",
+ "http",
+ "http-body",
+ "http-body-util",
+ "mime",
+ "pin-project-lite",
+ "rustversion",
+ "sync_wrapper 1.0.2",
+ "tower-layer",
+ "tower-service",
+ "tracing",
+]
+
 [[package]]
 name = "backtrace"
 version = "0.3.71"
@@ -84,6 +150,12 @@ version = "1.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1fd0f2584146f6f2ef48085050886acf353beff7305ebd1ae69500e27c67f64b"
 
+[[package]]
+name = "bytes"
+version = "1.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "325918d6fe32f23b19878fe4b34794ae41fc19ddbe53b10571a4874d44ffd39b"
+
 [[package]]
 name = "cc"
 version = "1.2.2"
@@ -110,6 +182,7 @@ dependencies = [
  "color-eyre",
  "eyre",
  "insta",
+ "pathdiff",
  "proptest",
  "tracing",
  "tracing-error",
@@ -224,6 +297,48 @@ version = "1.0.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3f9eec918d3f24069decb9af1554cad7c880e2da24a9afd88aca000531ab82c1"
 
+[[package]]
+name = "form_urlencoded"
+version = "1.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e13624c2627564efccf4934284bdd98cbaa14e79b0b5a141218e507b3a823456"
+dependencies = [
+ "percent-encoding",
+]
+
+[[package]]
+name = "futures-channel"
+version = "0.3.31"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2dff15bf788c671c1934e366d07e30c1814a8ef514e1af724a602e8a2fbe1b10"
+dependencies = [
+ "futures-core",
+]
+
+[[package]]
+name = "futures-core"
+version = "0.3.31"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "05f29059c0c2090612e8d742178b0580d2dc940c837851ad723096f87af6663e"
+
+[[package]]
+name = "futures-task"
+version = "0.3.31"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f90f7dce0722e95104fcb095585910c0977252f286e354b5e3bd38902cd99988"
+
+[[package]]
+name = "futures-util"
+version = "0.3.31"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9fa08315bb612088cc391249efdc3bc77536f16c91f6cf495e6fbe85b20a4a81"
+dependencies = [
+ "futures-core",
+ "futures-task",
+ "pin-project-lite",
+ "pin-utils",
+]
+
 [[package]]
 name = "generator"
 version = "0.8.3"
@@ -254,6 +369,87 @@ version = "0.28.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4271d37baee1b8c7e4b708028c57d816cf9d2434acb33a549475f78c181f6253"
 
+[[package]]
+name = "http"
+version = "1.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f16ca2af56261c99fba8bac40a10251ce8188205a4c448fbb745a2e4daa76fea"
+dependencies = [
+ "bytes",
+ "fnv",
+ "itoa",
+]
+
+[[package]]
+name = "http-body"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1efedce1fb8e6913f23e0c92de8e62cd5b772a67e7b3946df930a62566c93184"
+dependencies = [
+ "bytes",
+ "http",
+]
+
+[[package]]
+name = "http-body-util"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "793429d76616a256bcb62c2a2ec2bed781c8307e797e2598c50010f2bee2544f"
+dependencies = [
+ "bytes",
+ "futures-util",
+ "http",
+ "http-body",
+ "pin-project-lite",
+]
+
+[[package]]
+name = "httparse"
+version = "1.9.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7d71d3574edd2771538b901e6549113b4006ece66150fb69c0fb6d9a2adae946"
+
+[[package]]
+name = "httpdate"
+version = "1.0.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "df3b46402a9d5adb4c86a0cf463f42e19994e3ee891101b1841f30a545cb49a9"
+
+[[package]]
+name = "hyper"
+version = "1.5.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "97818827ef4f364230e16705d4706e2897df2bb60617d6ca15d598025a3c481f"
+dependencies = [
+ "bytes",
+ "futures-channel",
+ "futures-util",
+ "http",
+ "http-body",
+ "httparse",
+ "httpdate",
+ "itoa",
+ "pin-project-lite",
+ "smallvec",
+ "tokio",
+]
+
+[[package]]
+name = "hyper-util"
+version = "0.1.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "df2dcfbe0677734ab2f3ffa7fa7bfd4706bfdc1ef393f2ee30184aed67e631b4"
+dependencies = [
+ "bytes",
+ "futures-util",
+ "http",
+ "http-body",
+ "hyper",
+ "pin-project-lite",
+ "tokio",
+ "tower-service",
+]
+
 [[package]]
 name = "indenter"
 version = "0.3.3"
@@ -283,6 +479,12 @@ dependencies = [
  "parking_lot",
 ]
 
+[[package]]
+name = "itoa"
+version = "1.0.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d75a2a4b1b190afb6f5425f10f6a8f959d2ea0b9c2b1d79553551850539e4674"
+
 [[package]]
 name = "lazy_static"
 version = "1.5.0"
@@ -351,12 +553,24 @@ dependencies = [
  "regex-automata 0.1.10",
 ]
 
+[[package]]
+name = "matchit"
+version = "0.7.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0e7465ac9959cc2b1404e8e2367b43684a6d13790fe23056cc8c6c5a6b7bcb94"
+
 [[package]]
 name = "memchr"
 version = "2.7.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "78ca9ab1a0babb1e7d5695e3530886289c18cf2f87ec19a575a0abdce112e3a3"
 
+[[package]]
+name = "mime"
+version = "0.3.17"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6877bb514081ee2a7ff5ef9de3281f14a4dd4bceac4c09388074a6b5df8a139a"
+
 [[package]]
 name = "minimal-lexical"
 version = "0.2.1"
@@ -372,6 +586,17 @@ dependencies = [
  "adler",
 ]
 
+[[package]]
+name = "mio"
+version = "1.0.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2886843bf800fba2e3377cff24abf6379b4c4d5c6681eaf9ea5b0d15090450bd"
+dependencies = [
+ "libc",
+ "wasi",
+ "windows-sys 0.52.0",
+]
+
 [[package]]
 name = "nom"
 version = "7.1.3"
@@ -455,12 +680,30 @@ dependencies = [
  "windows-targets",
 ]
 
+[[package]]
+name = "pathdiff"
+version = "0.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "df94ce210e5bc13cb6651479fa48d14f601d9858cfe0467f43ae157023b938d3"
+
+[[package]]
+name = "percent-encoding"
+version = "2.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e3148f5046208a5d56bcfc03053e3ca6334e51da8dfb19b6cdc8b306fae3283e"
+
 [[package]]
 name = "pin-project-lite"
 version = "0.2.15"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "915a1e146535de9163f3987b8944ed8cf49a18bb0056bcebcdcece385cece4ff"
 
+[[package]]
+name = "pin-utils"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8b870d8c151b6f2fb93e84a13146138f05d02ed11c7e7c54f8826aaaf7c9f184"
+
 [[package]]
 name = "ppv-lite86"
 version = "0.2.20"
@@ -643,6 +886,12 @@ dependencies = [
  "wait-timeout",
 ]
 
+[[package]]
+name = "ryu"
+version = "1.0.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f3cb5ba0dc43242ce17de99c180e96db90b235b8a9fdc9543c96d2209116bd9f"
+
 [[package]]
 name = "scoped-tls"
 version = "1.0.1"
@@ -655,6 +904,60 @@ version = "1.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "94143f37725109f92c262ed2cf5e59bce7498c01bcc1502d7b9afe439a4e9f49"
 
+[[package]]
+name = "serde"
+version = "1.0.215"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6513c1ad0b11a9376da888e3e0baa0077f1aed55c17f50e7b2397136129fb88f"
+dependencies = [
+ "serde_derive",
+]
+
+[[package]]
+name = "serde_derive"
+version = "1.0.215"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ad1e866f866923f252f05c889987993144fb74e722403468a4ebd70c3cd756c0"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "serde_json"
+version = "1.0.133"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c7fceb2473b9166b2294ef05efcb65a3db80803f0b03ef86a5fc88a2b85ee377"
+dependencies = [
+ "itoa",
+ "memchr",
+ "ryu",
+ "serde",
+]
+
+[[package]]
+name = "serde_path_to_error"
+version = "0.1.16"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "af99884400da37c88f5e9146b7f1fd0fbcae8f6eec4e9da38b67d05486f814a6"
+dependencies = [
+ "itoa",
+ "serde",
+]
+
+[[package]]
+name = "serde_urlencoded"
+version = "0.7.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d3491c14715ca2294c4d6a88f15e84739788c1d030eed8c110436aafdaa2f3fd"
+dependencies = [
+ "form_urlencoded",
+ "itoa",
+ "ryu",
+ "serde",
+]
+
 [[package]]
 name = "sharded-slab"
 version = "0.1.7"
@@ -670,18 +973,48 @@ version = "1.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0fda2ff0d084019ba4d7c6f371c95d8fd75ce3524c3cb8fb653a3023f6323e64"
 
+[[package]]
+name = "signal-hook-registry"
+version = "1.4.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a9e9e0b4211b72e7b8b6e85c807d36c212bdb33ea8587f7569562a84df5465b1"
+dependencies = [
+ "libc",
+]
+
 [[package]]
 name = "similar"
 version = "2.6.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1de1d4f81173b03af4c0cbed3c898f6bff5b870e4a7f5d6f4057d62a7a4b686e"
 
+[[package]]
+name = "small_to_console"
+version = "0.1.0"
+dependencies = [
+ "axum",
+ "cogs",
+ "cogs_runtime",
+ "rand",
+ "tokio",
+]
+
 [[package]]
 name = "smallvec"
 version = "1.13.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3c5e1a9a646d36c3599cd173a41282daf47c44583ad367b8e6837255952e5c67"
 
+[[package]]
+name = "socket2"
+version = "0.5.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c970269d99b64e60ec3bd6ad27270092a5394c4e309314b18ae3fe575695fbe8"
+dependencies = [
+ "libc",
+ "windows-sys 0.52.0",
+]
+
 [[package]]
 name = "syn"
 version = "2.0.90"
@@ -693,6 +1026,18 @@ dependencies = [
  "unicode-ident",
 ]
 
+[[package]]
+name = "sync_wrapper"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2047c6ded9c721764247e62cd3b03c09ffc529b2ba5b10ec482ae507a4a70160"
+
+[[package]]
+name = "sync_wrapper"
+version = "1.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0bf256ce5efdfa370213c1dabab5935a12e49f2c58d15e9eac2870d3b4f27263"
+
 [[package]]
 name = "tempfile"
 version = "3.14.0"
@@ -716,12 +1061,70 @@ dependencies = [
  "once_cell",
 ]
 
+[[package]]
+name = "tokio"
+version = "1.42.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5cec9b21b0450273377fc97bd4c33a8acffc8c996c987a7c5b319a0083707551"
+dependencies = [
+ "backtrace",
+ "bytes",
+ "libc",
+ "mio",
+ "parking_lot",
+ "pin-project-lite",
+ "signal-hook-registry",
+ "socket2",
+ "tokio-macros",
+ "windows-sys 0.52.0",
+]
+
+[[package]]
+name = "tokio-macros"
+version = "2.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "693d596312e88961bc67d7f1f97af8a70227d9f90c31bba5806eec004978d752"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "tower"
+version = "0.5.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2873938d487c3cfb9aed7546dc9f2711d867c9f90c46b889989a2cb84eba6b4f"
+dependencies = [
+ "futures-core",
+ "futures-util",
+ "pin-project-lite",
+ "sync_wrapper 0.1.2",
+ "tokio",
+ "tower-layer",
+ "tower-service",
+ "tracing",
+]
+
+[[package]]
+name = "tower-layer"
+version = "0.3.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "121c2a6cda46980bb0fcd1647ffaf6cd3fc79a013de288782836f6df9c48780e"
+
+[[package]]
+name = "tower-service"
+version = "0.3.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8df9b6e13f2d32c91b9bd719c00d1958837bc7dec474d94952798cc8e69eeec3"
+
 [[package]]
 name = "tracing"
 version = "0.1.41"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "784e0ac535deb450455cbfa28a6f0df145ea1bb7ae51b821cf5e7927fdcfbdd0"
 dependencies = [
+ "log",
  "pin-project-lite",
  "tracing-attributes",
  "tracing-core",
diff --git a/Cargo.toml b/Cargo.toml
index fee0d5e..cddd7a9 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -4,7 +4,7 @@ members = [
   "crates/codegen",
   "crates/parser",
   "integrations/axum"
-]
+, "examples/small_to_console"]
 resolver = "2"
 
 [workspace.dependencies]
@@ -12,9 +12,11 @@ eyre = "0.6"
 tracing = "0.1"
 
 # crates/
+cogs = { path = "." }
 cogs_ast = { path = "crates/ast" }
 cogs_codegen = { path = "crates/codegen" }
 cogs_parser = { path = "crates/parser" }
+cogs_runtime = { path = "crates/runtime" }
 
 [package]
 name = "cogs"
@@ -37,6 +39,7 @@ cogs_parser.workspace = true
 proptest = "1.5.0"
 insta = "1.41.1"
 ariadne = "0.5.0"
+pathdiff = "0.2.3"
 
 # Test optimization
 [profile.dev.package]
diff --git a/crates/codegen/src/ir.rs b/crates/codegen/src/ir.rs
index cb0f537..294498a 100644
--- a/crates/codegen/src/ir.rs
+++ b/crates/codegen/src/ir.rs
@@ -102,7 +102,7 @@ impl Expression {
             ast::Element::Html(_html) => {
                 panic!("ast::Element::Html should not be used as attribute value")
             } // this is the only case where expression is used so we can mention that in the panic message
-            ast::Element::Block(_block) => {
+            ast::Element::Block(block) => {
                 todo!("code blocks are not supported as attribute values until Expression is implemented in the parser")
             }
         }
diff --git a/crates/codegen/src/lib.rs b/crates/codegen/src/lib.rs
index 3063ba9..71f8207 100644
--- a/crates/codegen/src/lib.rs
+++ b/crates/codegen/src/lib.rs
@@ -16,8 +16,7 @@ pub fn generate(ast: &ast::Component) -> eyre::Result<String> {
         trees: Vec::new(),
         intern_str: StrInterner::new(),
     };
-    let mut elements = ast.elements.iter();
-    for element in elements {
+    for element in ast.elements.iter() {
         generator
             .trees
             .push(Tree::from_ast(element, &generator.intern_str));
diff --git a/crates/runtime/src/lib.rs b/crates/runtime/src/lib.rs
index 0e713cc..513c2f9 100644
--- a/crates/runtime/src/lib.rs
+++ b/crates/runtime/src/lib.rs
@@ -5,7 +5,10 @@ pub trait Component {
     type Props;
     type Error;
 
-    fn render<'a>(&'a self, props: Self::Props) -> impl Future<Output = Result<String, Self::Error>> + Send + 'a;
+    fn render<'a>(
+        &'a self,
+        props: Self::Props,
+    ) -> impl Future<Output = Result<String, Self::Error>> + Send + 'a;
 }
 
 pub trait Render {
@@ -41,3 +44,15 @@ impl<T: Render> Render for Box<T> {
         (**self).render()
     }
 }
+
+#[macro_export]
+macro_rules! cogs_mod {
+    ($(#[$attr:meta])* $vis:vis $modname:ident) => {
+        $crate::cogs_mod!($(#[$attr])* $vis $modname, concat!("/", stringify!($modname), ".rs"));
+    };
+
+    ($(#[$attr:meta])* $vis:vis $modname:ident, $source:expr) => {
+        #[rustfmt::skip]
+        $(#[$attr])* $vis mod $modname { include!(concat!(env!("OUT_DIR"), $source)); }
+    };
+}
diff --git a/examples/small_to_console/Cargo.toml b/examples/small_to_console/Cargo.toml
new file mode 100644
index 0000000..5c96fbb
--- /dev/null
+++ b/examples/small_to_console/Cargo.toml
@@ -0,0 +1,13 @@
+[package]
+name = "small_to_console"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+cogs_runtime.workspace = true
+axum = "0.7"
+tokio = { version = "1", features = ["full"] }
+rand = "0.8.5"
+
+[build-dependencies]
+cogs.workspace = true
diff --git a/examples/small_to_console/build.rs b/examples/small_to_console/build.rs
new file mode 100644
index 0000000..84f06a9
--- /dev/null
+++ b/examples/small_to_console/build.rs
@@ -0,0 +1,3 @@
+fn main() {
+    cogs::build(std::env::current_dir().unwrap().join("cogs")).unwrap();
+}
diff --git a/examples/small_to_console/cogs/index.cog b/examples/small_to_console/cogs/index.cog
new file mode 100644
index 0000000..16bdd79
--- /dev/null
+++ b/examples/small_to_console/cogs/index.cog
@@ -0,0 +1,20 @@
+{ let random: u32 = rand::random(); }
+<html>
+  <head>
+    <title>cogs - small_to_console</title>
+  </head>
+  <body>
+    <h1>Hello World!</h1>
+    <p>This is an example of using <code style="margin: 0 1rem;">cogs::build</code> to generate a small html file.</p>
+
+    <p>The random number is: <h1>{random}</h1></p>
+
+    <footer>
+      <h4>Uses:</h4>
+      <ul>
+        <li><a href="https://github.com/filterunfiltered/cogs">cogs</a></li>
+        <li><a href="https://docs.rs/axum">axum</a></li>
+      </ul>
+    </footer>
+  </body>
+</html>
diff --git a/examples/small_to_console/src/main.rs b/examples/small_to_console/src/main.rs
new file mode 100644
index 0000000..d4fcc21
--- /dev/null
+++ b/examples/small_to_console/src/main.rs
@@ -0,0 +1,15 @@
+use axum::{response::Html, routing::get, Router};
+
+cogs_runtime::cogs_mod!(index);
+use cogs_runtime::Component;
+
+async fn index() -> Html<String> {
+    Html(index::Cog.render(()).await.unwrap())
+}
+
+#[tokio::main]
+async fn main() {
+    let app = Router::new().route("/", get(index));
+    let listener = tokio::net::TcpListener::bind("0.0.0.0:3000").await.unwrap();
+    axum::serve(listener, app).await.unwrap();
+}
diff --git a/src/lib.rs b/src/lib.rs
index 0c5230b..9089560 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -2,8 +2,10 @@ mod diagnostics;
 #[cfg(test)]
 mod tests;
 
+use std::path::Path;
+
 use tracing::level_filters::LevelFilter;
-use tracing_subscriber::{layer::SubscriberExt, util::SubscriberInitExt};
+use tracing_subscriber::layer::SubscriberExt;
 
 #[doc(hidden)]
 pub fn parse_cog(input: String, file: &str) -> eyre::Result<cogs_ast::Component> {
@@ -61,3 +63,41 @@ pub fn init_tracing() -> eyre::Result<()> {
 
     Ok(())
 }
+
+pub fn build(dir: impl AsRef<Path>) -> eyre::Result<()> {
+    let dir = dir.as_ref();
+    let out_dir = std::env::var_os("OUT_DIR").unwrap();
+
+    for entry in dir.read_dir()? {
+        let entry = entry?;
+        let path = entry.path();
+        if path.is_dir() {
+            build(&path)?;
+        } else if path.extension().map_or(false, |ext| ext == "cog") {
+            let _span = tracing::debug_span!("build cog", path = %path.display());
+            let contents = std::fs::read_to_string(&path)?;
+            let readable_path = if let Some(diffed) = std::env::current_dir()
+                .ok()
+                .and_then(|cwd| pathdiff::diff_paths(&path, &cwd))
+            {
+                diffed.display().to_string()
+            } else {
+                path.display().to_string()
+            };
+            let ast = parse_cog(contents, &readable_path)?;
+            tracing::debug!(?ast, "parsed");
+            let code = cogs_codegen::generate(&ast)?;
+            tracing::trace!(?code, "generated");
+            std::fs::write(
+                Path::new(&out_dir).join(
+                    pathdiff::diff_paths(&path, dir)
+                        .expect("path is not relative to dir for some reason")
+                        .with_extension("rs"),
+                ),
+                code,
+            )?;
+        }
+    }
+
+    Ok(())
+}