Add a annotation field to Field and with_annotation() fn

src/lib.rs

@@ -137,6 +137,9 @@ pub struct Field {
 
     /// Field documentation
     documentation: String,
+
+    /// Field annotation
+    annotation: String,
 }
 
 /// Defines an associated type.
@@ -1097,6 +1100,7 @@ impl Field {
             name: name.into(),
             ty: ty.into(),
             documentation: String::new(),
+            annotation: String::new(),
         }
     }
 
@@ -1106,6 +1110,11 @@ impl Field {
         self
     }
 
+    /// Set field's annotation.
+    pub fn with_annotation(&mut self, annotation: &str) -> &mut Self {
+        self.annotation = annotation.into();
+        self
+    }
 }
 
 // ===== impl Fields =====
@@ -1133,6 +1142,7 @@ impl Fields {
             name: name.to_string(),
             ty: ty.into(),
             documentation: String::new(),
+            annotation: String::new(),
         })
     }
 
@@ -1162,6 +1172,9 @@ impl Fields {
                         if !f.documentation.is_empty() {
                             write!(fmt, "/// {}\n", f.documentation)?;
                         }
+                        if !f.annotation.is_empty() {
+                            write!(fmt, "{}\n", f.annotation)?;
+                        }
                         write!(fmt, "{}: ", f.name)?;
                         f.ty.fmt(fmt)?;
                         write!(fmt, ",\n")?;
@@ -1238,6 +1251,7 @@ impl Impl {
             name: name.to_string(),
             ty: ty.into(),
             documentation: String::new(),
+            annotation: String::new(),
         });
 
         self
@@ -1382,7 +1396,11 @@ impl Function {
         self.args.push(Field {
             name: name.to_string(),
             ty: ty.into(),
+            // While a `Field` is used here, both `documentation`
+            // and `annotation` does not make sense for function arguments.
+            // Simply use empty strings.
             documentation: String::new(),
+            annotation: String::new(),
         });
 
         self

tests/codegen.rs

@@ -47,18 +47,33 @@ fn single_struct_documented_field() {
     let mut scope = Scope::new();
 
     let doc = "Field's documentation";
+    let anot = r#"#[serde(rename = "bar")]"#;
 
     let mut struct_ = Struct::new("Foo");
 
     let mut field1 = Field::new("one", "usize");
     field1.with_documentation(doc);
+    struct_.push_field(field1);
+
+    let mut field2 = Field::new("two", "usize");
+    field2.with_annotation(anot);
+    struct_.push_field(field2);
+
+    let mut field3 = Field::new("three", "usize");
+    field3.with_documentation(doc).with_annotation(anot);
+    struct_.push_field(field3);
 
     scope.push_struct(struct_);
 
     let expect = r#"
 struct Foo {
     /// Field's documentation
     one: usize,
+    #[serde(rename = "bar")]
+    two: usize,
+    /// Field's documentation
+    #[serde(rename = "bar")]
+    three: usize,
 }"#;
 
     assert_eq!(scope.to_string(), &expect[1..]);