nushell/crates/nu-protocol/src/maybe_owned.rs
Yehuda Katz e4226def16 Extract core stuff into own crates
This commit extracts five new crates:

- nu-source, which contains the core source-code handling logic in Nu,
  including Text, Span, and also the pretty.rs-based debug logic
- nu-parser, which is the parser and expander logic
- nu-protocol, which is the bulk of the types and basic conveniences
  used by plugins
- nu-errors, which contains ShellError, ParseError and error handling
  conveniences
- nu-textview, which is the textview plugin extracted into a crate

One of the major consequences of this refactor is that it's no longer
possible to `impl X for Spanned<Y>` outside of the `nu-source` crate, so
a lot of types became more concrete (Value became a concrete type
instead of Spanned<Value>, for example).

This also turned a number of inherent methods in the main nu crate into
plain functions (impl Value {} became a bunch of functions in the
`value` namespace in `crate::data::value`).
2019-12-02 10:54:12 -08:00

15 lines
265 B
Rust

#[derive(Debug)]
pub enum MaybeOwned<'a, T> {
Owned(T),
Borrowed(&'a T),
}
impl<T> MaybeOwned<'_, T> {
pub fn borrow(&self) -> &T {
match self {
MaybeOwned::Owned(v) => v,
MaybeOwned::Borrowed(v) => v,
}
}
}