Need a mechanism to write rust-version-specific code

[steveklabnik]

Issue by erickt
Wednesday Oct 17, 2012 at 20:00 GMT

For earlier discussion, see rust-lang/rust#3795

This issue was labelled with: A-attributes, E-easy, I-enhancement, P-low in the Rust repository

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Since rust is still going through active development, it's hard to write a library that works for both rust-0.4 and rust-incoming. We need a cfg #[cfg(rust_version="0.5")] to carve off chunks of code that have evolved in between versions.

If we want to get more fancy with these controls, I do have an old semantic version parser I wrote back in the 0.3 days. Maybe we could use something like that to let us write checks like:

#[cfg(rust_version=">=0.4-beta")]
#[cfg(rust_version="<=0.4")]
fn foo() { ... }

#[cfg(rust_version=">0.5")]
fn foo() { ... }

[Centril]

Closing in favor of #2523.