docs: update docs.

serde_valid/README.md

@@ -198,7 +198,36 @@ let s = SampleStruct { val: 1 };
 assert!(s.validate().is_ok());
 ```
 
-## Rules
+## Multi Fields Validation
+### Custom Validation
+Now, you can use `#[validate(custom)]` for multi fields validation.
+
+```rust
+use serde_json::json;
+use serde_valid::Validate;
+
+fn sample_validation(val1: i32, val2: &str) -> Result<(), serde_valid::validation::Error> {
+    Ok(())
+}
+
+#[derive(Validate)]
+struct SampleStruct {
+    #[validate(custom(|s| sample_validation(s.val1, &s.val2)))]
+    val1: i32,
+    val2: String,
+}
+
+let s = SampleStruct {
+    val1: 1,
+    val2: "val2".to_owned(),
+};
+
+assert!(s.validate().is_ok());
+```
+
+### Rules
+
+**Warning**: this feature is deprecated. Please use `#[validate(custom)]` instead.
 
 If you want to check multi fields validation, can use `#[rule]`.
 

serde_valid/src/lib.rs

@@ -180,7 +180,56 @@
 //! assert!(s.validate().is_ok());
 //! ```
 //!
-//! ## Rules
+//! And you can also use closure.
+//!
+//! ```rust
+//! use serde_valid::Validate;
+//!
+//! fn user_validation(_val: &i32, param1: bool) -> Result<(), serde_valid::validation::Error> {
+//!     Ok(())
+//! }
+//!
+//! #[derive(Validate)]
+//! struct SampleStruct {
+//!     #[validate(custom(|v| user_validation(v, true)))]
+//!     val: i32,
+//! }
+//!
+//! let s = SampleStruct { val: 1 };
+//!
+//! assert!(s.validate().is_ok());
+//! ```
+//!
+//! ## Multi Fields Validation
+//! ### Custom Validation
+//! Now, you can use `#[validate(custom)]` for multi fields validation.
+//!
+//! ```rust
+//! use serde_json::json;
+//! use serde_valid::Validate;
+//!
+//! fn sample_validation(val1: i32, val2: &str) -> Result<(), serde_valid::validation::Error> {
+//!     Ok(())
+//! }
+//!
+//! #[derive(Validate)]
+//! struct SampleStruct {
+//!     #[validate(custom(|s| sample_validation(s.val1, &s.val2)))]
+//!     val1: i32,
+//!     val2: String,
+//! }
+//!
+//! let s = SampleStruct {
+//!     val1: 1,
+//!     val2: "val2".to_owned(),
+//! };
+//!
+//! assert!(s.validate().is_ok());
+//! ```
+//!
+//! ### Rules
+//!
+//! **Warning**: this feature is deprecated. Please use `#[validate(custom)]` instead.
 //!
 //! If you want to check multi fields validation, can use `#[rule]`.
 //!
@@ -237,6 +286,48 @@
 //! assert!(s.validate().is_ok());
 //! ```
 //!
+//! And you can also use closure.
+//!
+//! ```rust
+//! use serde_json::json;
+//! use serde_valid::Validate;
+//!
+//! fn sample_rule(_val1: &i32, _val2: &str) -> Result<(), serde_valid::validation::Error> {
+//!     Ok(())
+//! }
+//!
+//! #[derive(Validate)]
+//! #[rule(|val1, val2| sample_rule(val2, val1))]
+//! struct SampleStruct {
+//!     val1: String,
+//!     val2: i32,
+//! }
+//!
+//! let s = SampleStruct {
+//!     val1: "val1".to_owned(),
+//!     val2: 1,
+//! };
+//!
+//! assert!(s.validate().is_ok());
+//! ```
+//!
+//! ```rust
+//! use serde_json::json;
+//! use serde_valid::Validate;
+//!
+//! fn sample_rule(_val1: &i32, _val2: &str) -> Result<(), serde_valid::validation::Error> {
+//!     Ok(())
+//! }
+//!
+//! #[derive(Validate)]
+//! #[rule(|_0, _1| sample_rule(_0, _1))]
+//! struct SampleStruct(i32, String);
+//!
+//! let s = SampleStruct(0, "1".to_owned());
+//!
+//! assert!(s.validate().is_ok());
+//! ```
+//!
 //! ## Validate Traits
 //!
 //! By implementing the validation trait, Your original type can uses Serde Valid validations.