derive-with 0.4.0

`#[derive(with)]` generates with-constructor for each field in struct.
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86

# A custom derive implementation for `#[derive(with)]`
![License](https://img.shields.io/badge/license-MIT-blue.svg)
[![Crates.io](https://img.shields.io/crates/v/derive-with.svg)](https://crates.io/crates/derive-with)

## Get started

1.Generate with-constructor for each field on named struct.
```rust
use derive_with::with;

#[derive(with, Default)]
pub struct Foo {
    pub a: i32,
    pub b: String,
}
```
This will generate code
```rust
impl Foo {
    pub fn with_a(mut self, a: impl Into<i32>) -> Self {
        self.a = a.into();
        self
    }
    pub fn with_b(mut self, b: impl Into<String>) -> Self {
        self.b = b.into();
        self
    }
}
```

2.Generate with-constructor for each field on tuple struct.
```rust
#[derive(with, Default)]
pub struct Bar (i32, String);
```
This will generate code
```rust
impl Bar {
    pub fn with_0(mut self, field_0: impl Into<i32>) -> Self {
        self.0 = field_0.into();
        self
    }
    pub fn with_1(mut self, field_1: impl Into<String>) -> Self {
        self.1 = field_1.into();
        self
    }
}
```

3.Generate with-constructor for specific fields on named struct.
```rust
#[derive(with, Default)]
#[with(a)]
pub struct Foo {
    pub a: i32,
    pub b: String,
}
```
This will generate code
```rust
impl Foo {
    pub fn with_a(mut self, a: impl Into<i32>) -> Self {
        self.a = a.into();
        self
    }
}
```

4.Generate with-constructor for specific fields on tuple struct.
```rust
#[derive(with, Default)]
#[with(1)]
pub struct Bar (i32, String);
```
This will generate code
```rust
impl Bar {
    pub fn with_1(mut self, field_1: impl Into<String>) -> Self {
        self.1 = field_1.into();
        self
    }
}
```

## References
- [nrc/derive-new](https://github.com/nrc/derive-new)