diff --git a/crates/ra_tools/src/codegen.rs b/crates/ra_tools/src/codegen.rs
index 8b13789179..edb01aceb6 100644
--- a/crates/ra_tools/src/codegen.rs
+++ b/crates/ra_tools/src/codegen.rs
@@ -1 +1,7 @@
+use std::path::Path;
 
+use crate::{Mode, Result};
+
+pub fn generate_ast(grammar_src: &Path, dst: &Path, mode: Mode) -> Result<()> {
+    Ok(())
+}
diff --git a/crates/ra_tools/src/lib.rs b/crates/ra_tools/src/lib.rs
index 96290ecc45..2cbb07ebfb 100644
--- a/crates/ra_tools/src/lib.rs
+++ b/crates/ra_tools/src/lib.rs
@@ -13,6 +13,8 @@ use itertools::Itertools;
 
 pub use teraron::{Mode, Overwrite, Verify};
 
+pub use self::codegen::generate_ast;
+
 pub type Result<T> = std::result::Result<T, Box<dyn Error>>;
 
 pub const GRAMMAR: &str = "crates/ra_syntax/src/grammar.ron";