feat: add compile cli

src/bin/compile.rs

@@ -0,0 +1,30 @@
+use std::process::exit;
+
+use itertools::Itertools;
+
+use nixjit::compile::compile;
+use nixjit::error::Error;
+use nixjit::error::Result;
+use nixjit::ir::downgrade;
+
+fn main() -> Result<()> {
+    let mut args = std::env::args();
+    if args.len() != 2 {
+        eprintln!("Usage: {} expr", args.next().unwrap());
+        exit(1);
+    }
+    args.next();
+    let expr = args.next().unwrap();
+    let root = rnix::Root::parse(&expr);
+    if !root.errors().is_empty() {
+        return Err(Error::ParseError(
+            root.errors().iter().map(|err| err.to_string()).join(";"),
+        ));
+    }
+    let expr = root.tree().expr().unwrap();
+    let downgraded = downgrade(expr)?;
+    let prog = compile(downgraded);
+    println!("{:?}", prog);
+
+    Ok(())
+}