test(examples): add examples

examples/basic.rs

@@ -0,0 +1,29 @@
+use serde::Deserialize;
+use serde_inline_default::serde_inline_default;
+use serde_json::json;
+
+#[serde_inline_default]
+#[derive(Deserialize)]
+struct Basic {
+    // if using `String` you have to call `.to_string()`
+    #[serde_inline_default("0.0.0.0".to_string())]
+    host: String,
+    // works without specifying the integer type at the end of the value (8080u16)
+    #[serde_inline_default(8080)]
+    port: u16,
+    // expressions are working too
+    #[serde_inline_default(serde_json::json!({}))]
+    random_third_party_type: serde_json::Value,
+}
+
+fn main() -> Result<(), serde_json::Error> {
+    // creating a empty json object to use the default value of all fields
+    let json_object = json!({});
+    let basic: Basic = serde_json::from_value(json_object)?;
+
+    assert_eq!(basic.host, "0.0.0.0".to_string());
+    assert_eq!(basic.port, 8080);
+    assert_eq!(basic.random_third_party_type, json!({}));
+
+    Ok(())
+}

examples/macro_rules.rs

@@ -0,0 +1,39 @@
+use serde_json::json;
+macro_rules! simple_macro {
+    (struct $name:ident { $($field:ident: $type:ty $(= $default:expr)?),*$(,)? }) => {
+        #[serde_inline_default::serde_inline_default]
+        #[derive(serde::Deserialize)]
+        struct $name {
+            $(
+                $(
+                    #[serde_inline_default($default)]
+                )?
+                $field: $type
+            ),*
+        }
+    }
+}
+
+fn main() -> Result<(), serde_json::Error> {
+    // `username` and `password` must be set when deserializing as no default value is defined for
+    // them. `secret` not as we're defining a default value for it
+    simple_macro! {
+        struct Example {
+            username: String,
+            password: String,
+            secret: String = "verysecretsecret".to_string()
+        }
+    }
+
+    let json_object = json!({
+        "username": "testuser",
+        "password": "testpassword"
+    });
+
+    let example: Example = serde_json::from_value(json_object)?;
+    assert_eq!(example.username, "testuser");
+    assert_eq!(example.password, "testpassword");
+    assert_eq!(example.secret, "verysecretsecret");
+
+    Ok(())
+}