https://github.com/olekspickle/serde_default_utils
A set of simple helper functions to cut corners with serde_default
https://github.com/olekspickle/serde_default_utils
convenience-functions default nostd rust serde
Last synced: about 2 months ago
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A set of simple helper functions to cut corners with serde_default
- Host: GitHub
- URL: https://github.com/olekspickle/serde_default_utils
- Owner: olekspickle
- License: apache-2.0
- Created: 2024-01-10T12:29:07.000Z (over 1 year ago)
- Default Branch: main
- Last Pushed: 2024-11-18T03:50:18.000Z (6 months ago)
- Last Synced: 2025-04-13T20:03:10.935Z (about 2 months ago)
- Topics: convenience-functions, default, nostd, rust, serde
- Language: Rust
- Homepage: https://crates.io/crates/serde_default_utils
- Size: 19.5 KB
- Stars: 12
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
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README
# serde_default_utils
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## Overview
This is a simple set of functions to make your life easier while working with defaults in serde.
Based on [const generic parameters](https://doc.rust-lang.org/reference/items/generics.html#const-generics).
Heavily inspired by discussions on issues about serde defaults, but mostly [this one](https://github.com/serde-rs/serde/issues/368)
## Kudos
- JohnTheCoolingFan posted this solution, I just made it available as crate and a macro that
helps to generate another const generic function for any const generic type.
- bytedream made a more powerful version of it, and although I still see const generic approach as more readable,
I have to admit that for strings it's superior, hence - included under the feature
## Example
```rust
use serde_default_utils::*;
use serde::{Deserialize, Serialize};
const JSON: &str =
r#"{
"yes_or_no":false,
"max":60,
"delta":-77,
"delimeter":"☀",
"motto":"I matter"
}"#;
const INLINE_JSON: &str =
r#"{
"inline_motto":"I matter even more",
"slice":["I", "matter", "even", "more"],
"slice_u64":[9000, 8000, 10000, 7000]
}"#;
const EMPTY_JSON: &str = r#"{}"#;
const MAX: u32 = 7;
#[derive(Serialize, Deserialize, Default)]
struct Config {
#[serde(default = "default_bool::")]
yes_or_no: bool,
#[serde(default = "default_i16::<-3>")]
delta: i16,
// you can even use consts right here
#[serde(default = "default_u32::")]
max: u32,
#[serde(default = "default_char::<'☀'>")]
delimeter: char,
}
#[cfg(feature = "inline")]
#[serde_inline_default]
#[derive(Serialize, Deserialize, Default)]
struct InlineConfig {
#[serde_inline_default("You matter even more".to_string())]
inline_motto: String,
#[serde_inline_default(vec!["You".into(), "matter".into(), "even".into(), "more".into()])]
slice: Vec,
#[serde_inline_default(vec![98712, 12346, 129389, 102937])]
slice_u64: Vec,
}
fn main() {
// existing json fields are not changed
let config: Config = serde_json::from_str(JSON).unwrap();
let s = serde_json::to_string(&config).unwrap();
assert_eq!(r#"{"yes_or_no":false,"delta":-77,"max":60,"delimeter":"☀"}"#, &s);
// if the field is not present - it is substituted with defaults
let config: Config = serde_json::from_str(EMPTY_JSON).unwrap();
let s = serde_json::to_string(&config).unwrap();
assert_eq!(r#"{"yes_or_no":true,"delta":-3,"max":7,"delimeter":"☀"}"#, &s);
// the default impl is just calling underlying type defaults unless you have a custom impl Default
let config = Config::default();
let s = serde_json::to_string(&config).unwrap();
assert_eq!(r#"{"yes_or_no":false,"delta":0,"max":0,"delimeter":"\u0000"}"#, &s);
// Inline
#[cfg(feature = "inline")]
{
// existing json fields are not changed
let config: InlineConfig = serde_json::from_str(INLINE_JSON).unwrap();
let s = serde_json::to_string(&config).unwrap();
assert_eq!(r#"{"inline_motto":"I matter even more","slice":["I","matter","even","more"],"slice_u64":[9000,8000,10000,7000]}"#, &s);
// if the field is not present - it is substituted with defaults
let config: InlineConfig = serde_json::from_str(EMPTY_JSON).unwrap();
let s = serde_json::to_string(&config).unwrap();
assert_eq!(r#"{"inline_motto":"You matter even more","slice":["You","matter","even","more"],"slice_u64":[98712,12346,129389,102937]}"#, &s);
// the default impl is just calling underlying type defaults unless you have a custom impl Default
let config = InlineConfig::default();
let s = serde_json::to_string(&config).unwrap();
assert_eq!(r#"{"inline_motto":"","slice":[],"slice_u64":[]}"#, &s);
}
}
```
License: MIT OR Apache-2.0