1 files changed, 45 insertions, 0 deletions
diff --git a/syn/codegen/src/gen.rs b/syn/codegen/src/gen.rs
new file mode 100644
index 0000000..ef43182
--- /dev/null
+++ b/syn/codegen/src/gen.rs
@@ -0,0 +1,45 @@
+use inflections::Inflect;
+use proc_macro2::{Ident, Span, TokenStream};
+use quote::quote;
+use syn_codegen::{Data, Definitions, Features, Node};
+
+pub const TERMINAL_TYPES: &[&str] = &["Span", "Ident"];
+
+pub fn under_name(name: &str) -> Ident {
+    Ident::new(&name.to_snake_case(), Span::call_site())
+}
+
+pub fn traverse(
+    defs: &Definitions,
+    node: fn(&mut TokenStream, &mut TokenStream, &Node, &Definitions),
+) -> (TokenStream, TokenStream) {
+    let mut types = defs.types.clone();
+    for terminal in TERMINAL_TYPES {
+        types.push(Node {
+            ident: terminal.to_string(),
+            features: Features::default(),
+            data: Data::Private,
+            exhaustive: true,
+        });
+    }
+    types.sort_by(|a, b| a.ident.cmp(&b.ident));
+
+    let mut traits = TokenStream::new();
+    let mut impls = TokenStream::new();
+    for s in types {
+        if s.ident == "Reserved" {
+            continue;
+        }
+        let features = &s.features.any;
+        let features = match features.len() {
+            0 => quote!(),
+            1 => quote!(#[cfg(feature = #(#features)*)]),
+            _ => quote!(#[cfg(any(#(feature = #features),*))]),
+        };
+        traits.extend(features.clone());
+        impls.extend(features);
+        node(&mut traits, &mut impls, &s, defs);
+    }
+
+    (traits, impls)
+}