A derivable macro for declaring a builder pattern. This crate is highly inspired by derive_builder.
```rust use builder_pattern::Builder;
struct Person { #[into] name: String, age: i32, #[default(Gender::Nonbinary)] gender: Gender, }
let p1 = Person::new() // PersonBuilder<(), (), ()>
.name(String::from("Joe")) // PersonBuilder // Orders does not matter.
let p2 = Person::new() // PersonBuilder<(), (), ()>
.age(32) // PersonBuilder<(), i32, ()>
// // Add ```toml [dependencies]
builder-pattern = "0.3"
``` A field having this attribute will be considered as optional and the If this attribute is present, the builder function would not be generated for the field. This field requires Example: ```rust struct Test {
#[default(Uuid::new_v4())]
#[hidden]
id: Uuid,
name: String,
} let test1 = Test::new() // TestBuilder<(), ()>
.name(String::from("Joe")) // TestBuilder let test2 = Test::new() // TestBuilder<(), ()>
.name(String::from("Jack")) // TestBuilder A setter function for a field having this attribute will accept an Example: ```rust struct Test {
#[into]
pub name: String,
} let test = Test::new() // TestBuilder<()>
// Implement a validator for a field. ```rust struct Test {
#[validator(isnotempty)]
#[into]
pub name: String,
} fn isnotempty(name: String) -> Result let test1 = Test::new() // TestBuilder<()>
.name("Hello") // Ok(TestBuilder let test2 = Test::new() // TestBuilder<()>
.name("") // Err(String{ "Validation failed: Name cannot be empty." })
.unwrap() // panic!
.build();
``` This crate generates documentations for the builder functions. If you documentate the fields,
the builder functions for them also copy the documentations. Example code: ```rust struct Test {
/// A positive integer.
pub positive: i32, }
``` Generated code: `` /// A builder for impl TestBuilder impl impl The following code ```rust struct Person {
#[into]
#[validator(isnotempty)]
name: String,
age: i32,
#[default(Gender::Nonbinary)]
gender: Gender,
} ``` will generates: ```rust
struct PersonBuilder impl Person {
// Create an empty builder
fn new() -> PersonBuilder<(), (), ()> {
PersonBuilder {
name: None,
age: None,
// Default value
gender: Some(Gender::Nonbinary),
_phantom: PhantomData
}
}
} // Builder for // Builder for // Builder for // &str is implicitly converted into String
// because of into attribute!
.name("Jack") // PersonBuildername field required - Compilation error.
let p3 = Person::new() // PersonBuilder<(), (), ()>
.age(15) // PersonBuilder<(), i32, ()>
.build();
```Get Started
builder-pattern to Cargo.toml.Cargo.toml
Features
build function is allowed only the all of required fields are provided. No Result, No Unwrap. Just use it.Attributes
#[default(expr)]expr will be evaluated as a default value of the field. build function can be called without providing this field.#[hidden]default attribute.[derive(Builder)]
#[into]Into trait as a parameter. You can use this setter with implicit conversion.[derive(Builder)]
&str is implicitly converted into String.
.name("Hello") // TestBuilder#[validator(expr)]expr could be a validating function that takes the field's type and returns Result.[derive(Builder)]
Auto-Generated Documentions
Example
[derive(Builder)]
/// A integer having zero as a default value.
#[default(0)]
pub zero: i32,
rust
impl Test {
/// Creating a builder.
/// ## Required fields
/// ###positive
/// - Type:i32
///
/// A positive integer.
///
/// ## Optional fields
/// ###zero
/// - Type:i32
/// - Default:0`
///
/// A integer having zero as a default value.
fn new() -> TestBuilder<(), ()> {
TestBuilder {
_phatom: PhantomData,
positive: None,
zero: Some(0),
}
}
}Test.
struct TestBuilderi32
///
/// A positive integer.
pub fn positive(self, value: i32) -> TestBuilder0
///
/// A integer having zero as a default value.
pub fn zero(self, value: i32) -> TestBuilderHow it works
[derive(Builder)]
name.
implInto traits.
fn nameIntoType into String.
name: Some(value.into()),
age: self.age,
gender: self.gender,
_phantom: PhantomData,
}),
Err(e) => Err(format!("Validation failed: {:?}", e))
}
}
}age.
implgender.
implbuild function
// It can be called regardless of whether T3 is () or Gender.
implLicense