Add example for libafl_derive::Display

libafl_derive/src/lib.rs

@@ -77,16 +77,44 @@ pub fn libafl_serdeany_derive(input: TokenStream) -> TokenStream {
 /// Options: Some => inner type display None => "".
 /// Vec: inner type display space separated concatenation.
 /// Generics and other more or less exotic stuff are not supported.
+///
+/// # Examples
+///
+/// ```rust
+/// use libafl_derive;
+///
+/// #[derive(libafl_derive::Display)]
+/// struct MyStruct {
+///     foo: String,
+///     bar: Option<u32>,
+/// }
+/// ```
+///
+/// The above code will expand to:
+///
+/// ```rust
+/// struct MyStruct {
+///     foo: String,
+///     bar: Option<u32>,
+/// }
+///
+/// impl core::fmt::Display for MyStruct {
+///     fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+///         f.write_fmt(format_args!(" {0}", self.foo))?;
+///         if let Some(opt) = &self.bar {
+///             f.write_fmt(format_args!(" {0}", opt))?;
+///         }
+///         Ok(())
+///     }
+/// }
+/// ```
 #[proc_macro_derive(Display)]
 pub fn libafl_display(input: TokenStream) -> TokenStream {
     let DeriveInput { ident, data, .. } = parse_macro_input!(input as DeriveInput);
 
     if let Struct(s) = data {
         if let Named(fields) = s.fields {
-            let fields_fmt = fields
-                .named
-                .iter()
-                .map(libafl_display_field_by_type);
+            let fields_fmt = fields.named.iter().map(libafl_display_field_by_type);
 
             return quote! {
                 impl core::fmt::Display for #ident {