https://github.com/jamesmunns/toml-cfg

A procedural macro for configuring constant values across crates
https://github.com/jamesmunns/toml-cfg

Last synced: 12 days ago
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A procedural macro for configuring constant values across crates

• Host: GitHub
• URL: https://github.com/jamesmunns/toml-cfg
• Owner: jamesmunns
• License: apache-2.0
• Created: 2022-01-11T17:37:22.000Z (almost 3 years ago)
• Default Branch: main
• Last Pushed: 2024-02-22T09:48:26.000Z (9 months ago)
• Last Synced: 2024-10-09T07:10:13.026Z (30 days ago)
• Language: Rust
• Size: 18.6 KB
• Stars: 56
• Watchers: 3
• Forks: 6
• Open Issues: 6
• Metadata Files:
  • Readme: README.md
  • License: LICENSE-APACHE

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README

        
# `toml-cfg`

Rough ideas:

* Crates can declare variables that can be overridden

    * Anything const, e.g. usize, strings, etc.

* (Only) The "root crate" can override these variables by including a `cfg.toml` file

## Config file

```toml

# a toml-cfg file

[lib-one]

buffer_size = 4096

[lib-two]

greeting = "Guten Tag!"

```

## In the library

```rust

// lib-one

#[toml_cfg::toml_config]

pub struct Config {

    #[default(32)]

    buffer_size: usize,

}

// lib-two

#[toml_cfg::toml_config]

pub struct Config {

    #[default("hello")]

    greeting: &'static str,

}

```

## Look at what we get!

```shell

# Print the "buffer_size" value from the `lib-one` crate.

# Since it has no cfg.toml, we just get the default value.

$ cd pkg-example/lib-one

$ cargo run

    Finished dev [unoptimized + debuginfo] target(s) in 0.01s

     Running `target/debug/lib-one`

32

# Print the "greeting" value from the `lib-two` crate.

# Since it has no cfg.toml, we just get the default value.

$ cd ../lib-two

$ cargo run

   Compiling lib-two v0.1.0 (/home/james/personal/toml-cfg/pkg-example/lib-two)

    Finished dev [unoptimized + debuginfo] target(s) in 0.32s

     Running `target/debug/lib-two`

hello

# Print the "buffer_size" value from `lib-one`, and "greeting"

# from `lib-two`. Since we HAVE defined a `cfg.toml` file, the

# values defined there are used instead.

$ cd ../application

$ cargo run

   Compiling lib-two v0.1.0 (/home/james/personal/toml-cfg/pkg-example/lib-two)

   Compiling application v0.1.0 (/home/james/personal/toml-cfg/pkg-example/application)

    Finished dev [unoptimized + debuginfo] target(s) in 0.30s

     Running `target/debug/application`

4096

Guten Tag!

```