Emit fields as a json map of name to type

codegen/Cargo.toml

@@ -9,6 +9,7 @@ publish = false # this is an internal crate which should never be published
 syn = { path = "..", features = ["full", "extra-traits"] }
 quote = "0.6"
 failure = "0.1"
+indexmap = { version = "1.0", features = ["serde-1"] }
 inflections = "1.1"
 proc-macro2 = "0.4"
 rustfmt-nightly = { git = "https://github.com/rust-lang-nursery/rustfmt" }

codegen/src/gen.rs

@@ -11,6 +11,7 @@
 //! 3. The path to `syn` is hardcoded.
 
 use crate::types;
+use indexmap::IndexMap;
 use proc_macro2::TokenStream;
 
 use std::fs::File;
@@ -516,21 +517,21 @@ mod codegen {
             types::Node::Struct(ref v) => {
                 let mut fold_fields = TokenStream::new();
 
-                for field in v.fields() {
-                    let id = Ident::new(field.ident(), Span::call_site());
+                for (field, ty) in v.fields() {
+                    let id = Ident::new(field, Span::call_site());
                     let ref_toks = Owned(quote!(_i.#id));
-                    let visit_field = visit(field.ty(), v.features(), defs, Visit, &ref_toks)
+                    let visit_field = visit(ty, v.features(), defs, Visit, &ref_toks)
                         .unwrap_or_else(|| noop_visit(Visit, &ref_toks));
                     visit_impl.append_all(quote! {
                         #visit_field;
                     });
                     let visit_mut_field =
-                        visit(field.ty(), v.features(), defs, VisitMut, &ref_toks)
+                        visit(ty, v.features(), defs, VisitMut, &ref_toks)
                             .unwrap_or_else(|| noop_visit(VisitMut, &ref_toks));
                     visit_mut_impl.append_all(quote! {
                         #visit_mut_field;
                     });
-                    let fold = visit(field.ty(), v.features(), defs, Fold, &ref_toks)
+                    let fold = visit(ty, v.features(), defs, Fold, &ref_toks)
                         .unwrap_or_else(|| noop_visit(Fold, &ref_toks));
 
                     fold_fields.append_all(quote! {
@@ -645,7 +646,7 @@ pub fn generate(defs: &types::Definitions) {
         defs.insert(types::Node::Struct(types::Struct::new(
                     tt.to_string(),
                     types::Features::default(),
-                    vec![],
+                    IndexMap::new(),
                     true)
         ));
     }

codegen/src/main.rs

@@ -13,6 +13,7 @@
 #![recursion_limit = "128"]
 #![allow(clippy::needless_pass_by_value)]
 
+extern crate indexmap;
 extern crate inflections;
 extern crate proc_macro2;
 #[macro_use]

codegen/src/parse.rs

@@ -1,5 +1,6 @@
 use crate::types;
 
+use indexmap::IndexMap;
 use syn::{Data, DataStruct, DeriveInput, Ident, Item};
 
 use std::collections::BTreeMap;
@@ -107,13 +108,13 @@ fn introspect_struct(
                     all_fields_pub = false;
                 }
 
-                types::Field::new(
+                (
                     field.ident.as_ref().unwrap().to_string(),
                     introspect_type(&field.ty, items, tokens),
                 )
             })
             .collect(),
-        syn::Fields::Unit => vec![],
+        syn::Fields::Unit => IndexMap::new(),
         _ => panic!("Struct representation not supported"),
     };
 

codegen/src/types.rs

@@ -1,3 +1,5 @@
+use indexmap::IndexMap;
+
 use std::collections::BTreeMap;
 use std::ops;
 
@@ -18,7 +20,7 @@ pub enum Node {
 pub struct Struct {
     ident: String,
     features: Features,
-    fields: Vec<Field>,
+    fields: IndexMap<String, Type>,
     all_fields_pub: bool,
 }
 
@@ -35,13 +37,6 @@ pub struct Variant {
     fields: Vec<Type>,
 }
 
-#[derive(Debug, Clone, Serialize)]
-pub struct Field {
-    ident: String,
-    #[serde(rename = "type")]
-    ty: Type,
-}
-
 #[derive(Debug, Clone, Serialize)]
 #[serde(rename_all = "lowercase")]
 pub enum Type {
@@ -107,7 +102,7 @@ impl Struct {
     pub fn new(
         ident: String,
         features: Features,
-        fields: Vec<Field>,
+        fields: IndexMap<String, Type>,
         all_fields_pub: bool,
     ) -> Struct {
         Struct {
@@ -122,7 +117,7 @@ impl Struct {
         &self.features
     }
 
-    pub fn fields(&self) -> &[Field] {
+    pub fn fields(&self) -> &IndexMap<String, Type> {
         &self.fields
     }
 
@@ -159,20 +154,6 @@ impl Variant {
     }
 }
 
-impl Field {
-    pub fn new(ident: String, ty: Type) -> Field {
-        Field { ident, ty }
-    }
-
-    pub fn ident(&self) -> &str {
-        &self.ident
-    }
-
-    pub fn ty(&self) -> &Type {
-        &self.ty
-    }
-}
-
 impl Punctuated {
     pub fn new(element: Type, punct: String) -> Self {
         Punctuated { element: Box::new(element), punct }