5 releases
0.2.0 | Feb 21, 2024 |
---|---|
0.1.3 | Jan 11, 2022 |
0.1.2 | Jan 11, 2022 |
0.1.1 | Jan 11, 2022 |
0.1.0 | Jan 11, 2022 |
#829 in Procedural macros
2,346 downloads per month
Used in 4 crates
(3 directly)
11KB
134 lines
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
# a toml-cfg file
[lib-one]
buffer_size = 4096
[lib-two]
greeting = "Guten tag!"
In the library
// 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!
# 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!
Dependencies
~0.5–1.1MB
~26K SLoC