Procedural derive macro for serializing a struct into a TOML template with field descriptions that is easily edited and deserialized.
Nested structs are not currently supported.
Make it easy to write a struct that defines a TOML template for optional configuration of an executable. Once the struct is deserialized with the derive macro implemented to_string_pretty_toml() function, it can be written to a (TOML) file, the file should be understandable without knowing any details of the binary. Deserializing the produced TOML file with no edits produceses the original struct with all optional fields None. Editing the produced TOML file will then deserialize into the original struct with those edited values.
A pub trait named TomlConfig with a single function with the signature: fn to_string_pretty_toml(&self) -> String
rust
pub trait TomlConfig {
fn to_string_pretty_toml(&self) -> String;
}
This macro was originally made for use in the fastPASTA crate.
The example is based on how the macro is used in fastPASTA.
The struct CustomChecks is implemented like this:
```rust use descriptivetomlderive::TomlConfig; use serde_derive::{Deserialize, Serialize};
pub trait TomlConfig { fn tostringpretty_toml(&self) -> String; }
// Deriving the TomlConfig macro which implements the TomlConfig trait.
pub struct CustomChecks {
// Use the description field attribute of the macro
#[description = "Number of CRU Data Packets expected in the data"]
// Use the example field attribute of the macro to show some example values
#[example = "20, 500532"]
cdps: Option
#[description = "Number of Physics (PhT) Triggers expected in the data"]
#[example = "0, 10"]
triggers_pht: Option<u32>,
#[description = "Legal Chip ordering for Outer Barrel (ML/OL). Needs to be a list of two lists of 7 chip IDs"]
#[example = "[[0, 1, 2, 3, 4, 5, 6], [8, 9, 10, 11, 12, 13, 14]]"]
chip_orders_ob: Option<(Vec<u8>, Vec<u8>)>,
} ```
The template file is generated e.g. like this.
rust
let toml = CustomChecks::default().to_string_pretty_toml();
std::fs::write("custom_checks.toml", toml).unwrap();
The contents of "custom_checks.toml" is now:
```toml
Editing all the fields to contain `Some` values could look like this:
toml
cdps = 20
triggers_pht = 0
chipordersob = [[0, 1, 2, 3, 4, 5, 6], [8, 9, 10, 11, 12, 13, 14]] ```
Deserializing from a TOML file is the same method as with any other TOML file, using serde_derive:
rust
let toml = std::fs::read_to_string("custom_checks.toml").unwrap();
let custom_checks = toml::from_str(&toml).unwrap();
A user that is already familiar with the configuration file might simply write
toml
cdps = 10
And input it to the binary. Which would deserialize into a struct with the cdps field containing Some(10), and the rest of the fields are None.