mirror of
https://github.com/rust-lang/rust.git
synced 2025-10-31 04:57:19 +00:00
49908b4d90
It currently has the syntax
`current_rustc_version!(env!("CFG_RELEASE"))` where the
`env!("CFG_RELEASE")` part looks like a normal expression but it is
actually parsed and processed by the `current_rustc_version` macro.
The documented rationale for this is that you'll find it if you grep for
`env!("CFG_RELEASE")`. But I think that's of very little use -- I would
personally grep for just "CFG_RELEASE" -- and it complicates the macro,
requiring the use of `syn`.
This commit simplifies the macro.
39 lines
1.3 KiB
Rust
39 lines
1.3 KiB
Rust
use proc_macro::TokenStream;
|
|
use proc_macro2::Span;
|
|
use quote::quote;
|
|
|
|
pub(crate) fn current_version(_input: TokenStream) -> TokenStream {
|
|
let env_var = "CFG_RELEASE";
|
|
TokenStream::from(match RustcVersion::parse_cfg_release(env_var) {
|
|
Ok(RustcVersion { major, minor, patch }) => quote!(
|
|
// The produced literal has type `rustc_session::RustcVersion`.
|
|
Self { major: #major, minor: #minor, patch: #patch }
|
|
),
|
|
Err(err) => syn::Error::new(Span::call_site(), format!("{env_var} env var: {err}"))
|
|
.into_compile_error(),
|
|
})
|
|
}
|
|
|
|
struct RustcVersion {
|
|
major: u16,
|
|
minor: u16,
|
|
patch: u16,
|
|
}
|
|
|
|
impl RustcVersion {
|
|
fn parse_cfg_release(env_var: &str) -> Result<Self, Box<dyn std::error::Error>> {
|
|
let value = proc_macro::tracked_env::var(env_var)?;
|
|
Self::parse_str(&value)
|
|
.ok_or_else(|| format!("failed to parse rustc version: {:?}", value).into())
|
|
}
|
|
|
|
fn parse_str(value: &str) -> Option<Self> {
|
|
// Ignore any suffixes such as "-dev" or "-nightly".
|
|
let mut components = value.split('-').next().unwrap().splitn(3, '.');
|
|
let major = components.next()?.parse().ok()?;
|
|
let minor = components.next()?.parse().ok()?;
|
|
let patch = components.next().unwrap_or("0").parse().ok()?;
|
|
Some(RustcVersion { major, minor, patch })
|
|
}
|
|
}
|