diff --git a/src/code_generator/generate.c b/src/code_generator/generate.c
new file mode 100644
index 00000000..8be71475
--- /dev/null
+++ b/src/code_generator/generate.c
@@ -0,0 +1,24 @@
+#include "code_generator/generate.h"
+#include <assert.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include "ast/ast_impl.h"
+
+void generate_code(AstRef ast) {
+  assert(ast);
+  switch (ast->tag) {
+    default:
+      error("Unimplemented: %d\n", ast->tag);
+      break;
+  }
+}
+
+void error(const char* message, ...) {
+  va_list args;
+  va_start(args, message);
+  vfprintf(stderr, message, args);
+  va_end(args);
+  fprintf(stderr, "\n");
+  exit(EXIT_FAILURE);
+}
diff --git a/src/code_generator/generate.h b/src/code_generator/generate.h
new file mode 100644
index 00000000..e9cde182
--- /dev/null
+++ b/src/code_generator/generate.h
@@ -0,0 +1,9 @@
+#ifndef KMC_C90_COMPILER_CODE_GENERATOR_GENERATE_H
+#define KMC_C90_COMPILER_CODE_GENERATOR_GENERATE_H
+
+#include "ast.h"
+
+void generate_code(AstRef ast);
+void error(const char* message, ...);
+
+#endif  /* KMC_C90_COMPILER_CODE_GENERATOR_GENERATE_H */