Simplify deserializer macro setup

instant-xml-macros/src/de.rs

@@ -3,36 +3,7 @@ use quote::quote;
 
 use crate::{ContainerMeta, FieldMeta, Namespace};
 
-struct Tokens {
-    enum_: TokenStream,
-    consts: TokenStream,
-    names: TokenStream,
-    match_: TokenStream,
-}
-
-impl Default for Tokens {
-    fn default() -> Self {
-        Self {
-            enum_: TokenStream::new(),
-            consts: TokenStream::new(),
-            names: TokenStream::new(),
-            match_: TokenStream::new(),
-        }
-    }
-}
-
-pub struct Deserializer {
-    out: TokenStream,
-}
-
-impl quote::ToTokens for Deserializer {
-    fn to_tokens(&self, tokens: &mut TokenStream) {
-        tokens.extend(self.out.clone());
-    }
-}
-
-impl Deserializer {
-    pub fn new(input: &syn::DeriveInput) -> Deserializer {
+pub(crate) fn from_xml(input: &syn::DeriveInput) -> TokenStream {
     let ident = &input.ident;
     let container_meta = ContainerMeta::from_derive(input);
     let default_namespace = match &container_meta.ns.uri {
@@ -75,7 +46,7 @@ impl Deserializer {
                             false => &mut elements_tokens,
                         };
 
-                            Self::process_field(
+                        process_field(
                             field,
                             index,
                             &mut declare_values,
@@ -106,7 +77,7 @@ impl Deserializer {
     let attr_type_match = attributes_tokens.match_;
 
     let name = ident.to_string();
-        let out = quote!(
+    quote!(
         impl #xml_impl_generics FromXml<'xml> for #ident #ty_generics #where_clause {
             fn deserialize<'cx>(deserializer: &'cx mut ::instant_xml::Deserializer<'cx, 'xml>) -> Result<Self, ::instant_xml::Error> {
                 use ::instant_xml::de::{Deserializer, Id, Node};
@@ -176,13 +147,11 @@ impl Deserializer {
                 name: #name,
             });
         }
-        );
+    )
+}
 
-        Deserializer { out }
-    }
-
-    #[allow(clippy::too_many_arguments)]
-    fn process_field(
+#[allow(clippy::too_many_arguments)]
+fn process_field(
     field: &syn::Field,
     index: usize,
     declare_values: &mut TokenStream,
@@ -190,7 +159,7 @@ impl Deserializer {
     tokens: &mut Tokens,
     field_meta: FieldMeta,
     container_meta: &ContainerMeta,
-    ) {
+) {
     let field_var = field.ident.as_ref().unwrap();
     let field_var_str = field_var.to_string();
     let const_field_var_str = Ident::new(&field_var_str.to_uppercase(), Span::call_site());
@@ -261,6 +230,23 @@ impl Deserializer {
             None => <#no_lifetime_type>::missing_value()?,
         },
     ));
+}
+
+struct Tokens {
+    enum_: TokenStream,
+    consts: TokenStream,
+    names: TokenStream,
+    match_: TokenStream,
+}
+
+impl Default for Tokens {
+    fn default() -> Self {
+        Self {
+            enum_: TokenStream::new(),
+            consts: TokenStream::new(),
+            names: TokenStream::new(),
+            match_: TokenStream::new(),
+        }
     }
 }
 

instant-xml-macros/src/lib.rs

@@ -6,7 +6,7 @@ mod ser;
 use std::collections::BTreeMap;
 
 use proc_macro2::{Delimiter, Group, Ident, Literal, Punct, TokenStream, TokenTree};
-use quote::{quote, ToTokens};
+use quote::ToTokens;
 use syn::parse_macro_input;
 use syn::punctuated::Punctuated;
 use syn::token::Colon2;
@@ -20,12 +20,7 @@ pub fn to_xml(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
 #[proc_macro_derive(FromXml, attributes(xml))]
 pub fn from_xml(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
     let ast = parse_macro_input!(input as syn::DeriveInput);
-
-    let deserializer = de::Deserializer::new(&ast);
-
-    proc_macro::TokenStream::from(quote!(
-        #deserializer
-    ))
+    proc_macro::TokenStream::from(de::from_xml(&ast))
 }
 
 #[derive(Default)]