Update homework 1 and 2

src/irgen/mod.rs

@@ -0,0 +1,26 @@
+use core::fmt;
+
+use lang_c::ast::*;
+
+use crate::*;
+
+#[derive(Default)]
+pub struct Irgen {}
+
+#[derive(Debug, PartialEq)]
+pub struct IrgenError {}
+
+impl fmt::Display for IrgenError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "IrgenError")
+    }
+}
+
+impl Translate<TranslationUnit> for Irgen {
+    type Target = ir::TranslationUnit;
+    type Error = IrgenError;
+
+    fn translate(&mut self, _unit: &TranslationUnit) -> Result<Self::Target, Self::Error> {
+        todo!("homework 2")
+    }
+}