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/*!
# Debug Helper
This crate provides declarative macros to help you implement the `Debug` trait manually.
Instead of this crate, in most cases, you can use the [`educe`](https://crates.io/crates/educe) crate to implement the `Debug` trait.
## Examples
For structs,
```rust
use std::fmt::{self, Formatter, Debug};
pub struct A {
pub f1: u8,
pub f2: i16,
pub f3: f64,
}
impl Debug for A {
fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), fmt::Error> {
debug_helper::impl_debug_for_struct!(A, f, self, .f1, (.f3, "{:.3}", self.f3));
}
}
let a = A {
f1: 1,
f2: 2,
f3: std::f64::consts::PI,
};
println!("{:#?}", a);
/*
A {
f1: 1,
f3: 3.142,
}
*/
```
For tuple structs,
```rust
use std::fmt::{self, Formatter, Debug};
pub struct A(pub u8, pub i16, pub f64);
impl Debug for A {
fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), fmt::Error> {
debug_helper::impl_debug_for_tuple_struct!(A, f, self, .0, (.2, "{:.3}", self.2));
}
}
let a = A(1, 2, std::f64::consts::PI);
println!("{:#?}", a);
/*
A(
1,
3.142,
)
*/
```
For enums (without the enum name),
```rust
use std::fmt::{self, Formatter, Debug};
pub enum A {
V1,
V2(u8, i16, f64),
V3 {
f1: u8,
f2: i16,
f3: f64,
},
}
impl Debug for A {
fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), fmt::Error> {
debug_helper::impl_debug_for_enum!(A::{V1, (V2(f1, _, f3): (.f1, (.f3, "{:.3}", f3))), {V3{f1, f2: _, f3}: (.f1, (.f3, "{:.3}", f3))}}, f, self);
}
}
let a = A::V1;
let b = A::V2(1, 2, std::f64::consts::PI);
let c = A::V3{
f1: 1,
f2: 2,
f3: std::f64::consts::PI,
};
println!("{:#?}", a);
println!("{:#?}", b);
println!("{:#?}", c);
/*
V1
V2(
1,
3.142,
)
V3 {
f1: 1,
f3: 3.142,
}
*/
```
For enums (with the enum name),
```rust
use std::fmt::{self, Formatter, Debug};
pub enum A {
V1,
V2(u8, i16, f64),
V3 {
f1: u8,
f2: i16,
f3: f64,
},
}
impl Debug for A {
fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), fmt::Error> {
debug_helper::impl_debug_for_enum!({A::V1, (V2(f1, _, f3): (.f1, (.f3, "{:.3}", f3))), {V3{f1, f2: _, f3}: (.f1, (.f3, "{:.3}", f3))}}, f, self);
}
}
let a = A::V1;
let b = A::V2(1, 2, std::f64::consts::PI);
let c = A::V3{
f1: 1,
f2: 2,
f3: std::f64::consts::PI,
};
println!("{:#?}", a);
println!("{:#?}", b);
println!("{:#?}", c);
/*
A::V1
A::V2(
1,
3.142,
)
A::V3 {
f1: 1,
f3: 3.142,
}
*/
```
Ghost fields,
```rust
use std::fmt::{self, Formatter, Debug};
pub struct A {
pub f1: u8,
pub f2: i16,
pub f3: f64,
}
impl Debug for A {
fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), fmt::Error> {
debug_helper::impl_debug_for_struct!(A, f, self, .f1, (.f3, "{:.3}", self.f3), (.sum, "{:.3}", self.f1 as f64 + self.f2 as f64 + self.f3));
}
}
let a = A {
f1: 1,
f2: 2,
f3: std::f64::consts::PI,
};
println!("{:#?}", a);
/*
A {
f1: 1,
f3: 3.142,
sum: 6.142,
}
*/
```
```rust
use std::fmt::{self, Formatter, Debug};
pub struct A(pub u8, pub i16, pub f64);
impl Debug for A {
fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), fmt::Error> {
debug_helper::impl_debug_for_tuple_struct!(A, f, self, .0, (.2, "{:.3}", self.2), (.3, "{:.3}", self.0 as f64 + self.1 as f64 + self.2));
}
}
let a = A(1, 2, std::f64::consts::PI);
println!("{:#?}", a);
/*
A(
1,
3.142,
6.142,
)
*/
```
Fake structs,
```rust
use std::fmt::{self, Formatter, Debug};
pub struct A(pub u8, pub i16, pub f64);
impl Debug for A {
fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), fmt::Error> {
debug_helper::impl_debug_for_struct!(A, f, self, let .f1 = self.0, let .f2 = self.1, let .f3 = self.2);
}
}
let a = A(1, 2, std::f64::consts::PI);
println!("{:#?}", a);
/*
A {
f1: 1,
f2: 2,
f3: 3.141592653589793,
}
*/
```
Fake tuple structs,
```rust
use std::fmt::{self, Formatter, Debug};
pub struct A {
pub f1: u8,
pub f2: i16,
pub f3: f64,
}
impl Debug for A {
fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), fmt::Error> {
debug_helper::impl_debug_for_tuple_struct!(A, f, self, let .0 = self.f1, let .1 = self.f2, let .2 = self.f3);
}
}
let a = A {
f1: 1,
f2: 2,
f3: std::f64::consts::PI,
};
println!("{:#?}", a);
/*
A(
1,
2,
3.141592653589793,
)
*/
```
## TODO
1. Fake enum struct variants and tuple variants.
1. Enum variants can be renamed.
*/
#![no_std]
extern crate alloc;
use alloc::fmt::{Debug, Formatter, Result as FormatResult};
use alloc::string::String;
#[doc(hidden)]
pub struct RawString(pub String);
impl Debug for RawString {
fn fmt(&self, f: &mut Formatter<'_>) -> FormatResult {
if f.alternate() {
f.write_str(self.0.replace('\n', "\n ").as_str())
} else {
f.write_str(self.0.as_str())
}
}
}
#[macro_export]
macro_rules! impl_debug_for_struct {
// TODO unit struct
($struct_name:ident, $formatter:expr $(, $self:expr)? $(,)*) => {
return $formatter.write_str(stringify!($struct_name));
};
// TODO struct
($struct_name:ident, $formatter:expr, $self:expr, $( $(.$field:ident)? $((.$field_2:ident, $($field_2_fmt:tt)+))? $(let .$field_3:ident = $field_3_value:expr)? ),* $(,)*) => {
{
let mut builder = $formatter.debug_struct(stringify!($struct_name));
$(
$(
builder.field(stringify!($field), &$self.$field);
)?
$(
builder.field(stringify!($field_2), &$crate::RawString(format!($($field_2_fmt)*)));
)?
$(
builder.field(stringify!($field_3), &$field_3_value);
)?
)*
return builder.finish();
}
};
}
#[macro_export]
macro_rules! impl_debug_for_tuple_struct {
// TODO unit tuple struct
($struct_name:ident, $formatter:expr $(, $self:expr)? $(,)*) => {
return $formatter.write_str(stringify!($struct_name));
};
// TODO tuple struct
($struct_name:ident, $formatter:expr, $self:expr, $( $(.$field:tt)? $((.$field_2:tt, $($field_2_fmt:tt)+))? $(let .$field_3:tt = $field_3_value:expr)? ),* $(,)*) => {
{
let mut builder = $formatter.debug_tuple(stringify!($struct_name));
$(
$(
builder.field(&$self.$field);
)?
$(
builder.field(&$crate::RawString(format!($($field_2_fmt)*)));
)?
$(
builder.field(&$field_3_value);
)?
)*
return builder.finish();
}
}
}
#[macro_export]
macro_rules! impl_debug_for_enum {
// TODO enum
($enum_name:ident::{$( $($variant_unit:ident)? $(($variant_tuple:ident ($($tuple:tt)*) $(:($( $(.$t_field:tt)? $((.$t_field_2:tt, $($t_field_2_fmt:tt)+))? $(let .$t_field_3:tt = $t_field_3_value:expr)? ),* $(,)*))? ) )? $({$variant_struct:ident {$($struct:tt)*} $(:($( $(.$s_field:tt)? $((.$s_field_2:tt, $($s_field_2_fmt:tt)+))? $(let .$s_field_3:ident = $s_field_3_value:expr)? ),* $(,)*))? })? ),+ $(,)*}, $formatter:expr, $self:expr $(,)*) => {
{
match $self {
$(
$(
Self::$variant_unit => {
return $formatter.write_str(stringify!($variant_unit));
}
)?
$(
Self::$variant_tuple ($($tuple)*)=> {
let mut builder = $formatter.debug_tuple(stringify!($variant_tuple));
$(
$(
$(
builder.field(&$t_field);
)?
$(
builder.field(&$crate::RawString(format!($($t_field_2_fmt)*)));
)?
$(
builder.field(&$t_field_3_value);
)?
)*
)?
return builder.finish();
}
)?
$(
Self::$variant_struct {$($struct)*}=> {
let mut builder = $formatter.debug_struct(stringify!($variant_struct));
$(
$(
$(
builder.field(stringify!($s_field), &$s_field);
)?
$(
builder.field(stringify!($s_field_2), &$crate::RawString(format!($($s_field_2_fmt)*)));
)?
$(
builder.field(stringify!($s_field_3), &$s_field_3_value);
)?
)*
)?
return builder.finish();
}
)?
)+
}
}
};
// TODO enum full path
({$enum_name:ident::$( $($variant_unit:ident)? $(($variant_tuple:ident ($($tuple:tt)*) $(:($( $(.$t_field:tt)? $((.$t_field_2:tt, $($t_field_2_fmt:tt)+))? $(let .$t_field_3:tt = $t_field_3_value:expr)? ),* $(,)*))? ) )? $({$variant_struct:ident {$($struct:tt)*} $(:($( $(.$s_field:tt)? $((.$s_field_2:tt, $($s_field_2_fmt:tt)+))? $(let .$s_field_3:ident = $s_field_3_value:expr)? ),* $(,)*))? })? ),+ $(,)*}, $formatter:expr, $self:expr $(,)*) => {
{
match $self {
$(
$(
Self::$variant_unit => {
$formatter.write_str(stringify!($enum_name))?;
$formatter.write_str("::")?;
return $formatter.write_str(stringify!($variant_unit));
}
)?
$(
Self::$variant_tuple ($($tuple)*)=> {
let mut builder = $formatter.debug_tuple(&format!("{}::{}", stringify!($enum_name), stringify!($variant_tuple)));
$(
$(
$(
builder.field(&$t_field);
)?
$(
builder.field(&$crate::RawString(format!($($t_field_2_fmt)*)));
)?
$(
builder.field(&$t_field_3_value);
)?
)*
)?
return builder.finish();
}
)?
$(
Self::$variant_struct {$($struct)*}=> {
let mut builder = $formatter.debug_struct(&format!("{}::{}", stringify!($enum_name), stringify!($variant_struct)));
$(
$(
$(
builder.field(stringify!($s_field), &$s_field);
)?
$(
builder.field(stringify!($s_field_2), &$crate::RawString(format!($($s_field_2_fmt)*)));
)?
$(
builder.field(stringify!($s_field_3), &$s_field_3_value);
)?
)*
)?
return builder.finish();
}
)?
)+
}
}
};
}