feat: support flattened items and comma seperated arguments

README.md

@@ -57,7 +57,7 @@ Config::to_toml_example("example.toml");  // write example to a file
 let example = Config::toml_example();
 ```
 
-Toml example base on the doc string of each field
+Toml example base on the docstring of each field
 ```toml
 # Config is to arrange something or change the controls on a computer or other device
 # so that it can be used in a particular way
@@ -135,8 +135,7 @@ Please add `#[toml_example(nesting)]`, or `#[toml_example(nesting = prefix)]` on
   #[allow(dead_code)]
   struct Node {
       /// Services are running in the node
-      #[toml_example(nesting)]
-      #[toml_example(default = http)]
+      #[toml_example(default = http, nesting)]
       services: HashMap<String, Service>,
   }
 ```
@@ -149,43 +148,52 @@ Please add `#[toml_example(nesting)]`, or `#[toml_example(nesting = prefix)]` on
 port = 80
 
 ```
-If you want an optional field become a required field in example,
-place the `#[toml_example(require)]` on the field.
-If you want to skip some field you can use `#[toml_example(skip)]`,
-the `#[serde(skip)]`, `#[serde(skip_deserializing)]` also works.
+
+## Flattening
+Flattening means treating the fields of a nested struct as if they were defined directly in the wrapping struct.
 ```rust
-use toml_example::TomlExample;
 #[derive(TomlExample)]
-struct Config {
-    /// Config.a is an optional number
-    #[toml_example(require)]
-    a: Option<usize>,
-    /// Config.b is an optional string
-    #[toml_example(require)]
-    b: Option<String>,
-    #[toml_example(require)]
-    #[toml_example(default = "third")]
-    c: Option<String>,
-    #[toml_example(skip)]
-    d: usize,
+struct ItemWrapper {
+    #[toml_example(flatten, nesting)]
+    item: Item,
+}
+#[derive(TomlExample)]
+struct Item {
+    value: String,
 }
+
+assert_eq!(ItemWrapper::toml_example(), Item::toml_example());
 ```
-```toml
-# Config.a is an optional number
-a = 0
 
-# Config.b is an optional string
-b = ""
+This works with maps too!
 
-c = "third"
+```rust
+#[derive(TomlExample, Deserialize)]
+struct MainConfig {
+    #[serde(flatten)]
+    #[toml_example(nesting)]
+    nested: HashMap<String, ConfigItem>,
+}
+#[derive(TomlExample, Deserialize)]
+struct ConfigItem {
+    #[toml_example(default = false)]
+    enabled: bool,
+}
 
+let example = MainConfig::toml_example();
+assert!(toml::from_str::<MainConfig>(&example).is_ok());
+println!("{example}");
+```
+```toml
+[example]
+enabled = false
 ```
 
 ## Enum Field
 You can also use fieldless enums, but you have to annotate them with `#[toml_example(enum)]` or
 `#[toml_example(is_enum)]` if you mind the keyword highlight you likely get when writing "enum".
 When annotating a field with `#[toml_example(default)]` it will use the [Debug](core::fmt::Debug) implementation.
-However for non-TOML datatypes like enums, this does not work as the value needs to be treated as a string in TOML.
+However for non-TOML data types like enums, this does not work as the value needs to be treated as a string in TOML.
 The `#[toml_example(enum)]` attribute just adds the needed quotes around the [Debug](core::fmt::Debug) implementation
 and can be omitted if a custom [Debug](core::fmt::Debug) already includes those.
 
@@ -194,8 +202,7 @@ use toml_example::TomlExample;
 #[derive(TomlExample)]
 struct Config {
     /// Config.priority is an enum
-    #[toml_example(default)]
-    #[toml_example(enum)]
+    #[toml_example(enum, default)]
     priority: Priority,
 }
 #[derive(Debug, Default)]
@@ -211,6 +218,38 @@ priority = "Important"
 "#)
 ```
 
+## More
+If you want an optional field become a required field in example,
+place the `#[toml_example(require)]` on the field.
+If you want to skip some field you can use `#[toml_example(skip)]`,
+the `#[serde(skip)]`, `#[serde(skip_deserializing)]` also works.
+```rust
+use toml_example::TomlExample;
+#[derive(TomlExample)]
+struct Config {
+    /// Config.a is an optional number
+    #[toml_example(require)]
+    a: Option<usize>,
+    /// Config.b is an optional string
+    #[toml_example(require)]
+    b: Option<String>,
+    #[toml_example(require, default = "third")]
+    c: Option<String>,
+    #[toml_example(skip)]
+    d: usize,
+}
+```
+```toml
+# Config.a is an optional number
+a = 0
+
+# Config.b is an optional string
+b = ""
+
+c = "third"
+
+```
+
 [crates-badge]: https://img.shields.io/crates/v/toml-example.svg
 [crate-url]: https://crates.io/crates/toml-example
 [mit-badge]: https://img.shields.io/badge/license-MIT-blue.svg