Tracking Issue for `{str, [T], Path}::trim_prefix` and `{str, [T]}::trim_suffix`

[deven]

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Feature gate: #![feature(trim_prefix_suffix)]

This is a tracking issue for adding trim_prefix and trim_suffix methods to str that remove at most one occurrence of a specified prefix or suffix while always returning a string slice (rather than Option<&str>), enabling easy method chaining.¹

Public API

impl str {
    pub fn trim_prefix<P>(&self, prefix: P) -> &str
    where
        P: Pattern;

    pub fn trim_suffix<P>(&self, suffix: P) -> &str
    where
        P: Pattern,
        for<'a> P::Searcher<'a>: ReverseSearcher<'a>;
}

impl [T] {
    pub fn trim_prefix<P>(&self, prefix: &P) -> &[T]
    where
        P: SlicePattern<Item = T> + ?Sized,
        T: PartialEq;

    pub fn trim_suffix<P>(&self, suffix: &P) -> &[T]
    where
        P: SlicePattern<Item = T> + ?Sized,
        T: PartialEq;
}

impl Path {
    pub fn trim_prefix<P>(&self, base: P) -> &Path
    where
        P: AsRef<Path>;
}

Steps / History

(Remember to update the S-tracking-* label when checking boxes.)

• Implementation: Add trim_prefix and trim_suffix methods for both slice and str types. #142331
• Final comment period (FCP)²
• Stabilization PR

Unresolved Questions

• None yet.

Footnotes

1. https://github.com/rust-lang/libs-team/issues/597 ↩

2. https://std-dev-guide.rust-lang.org/feature-lifecycle/stabilization.html ↩

[deven]

@Amanieu, I just noticed that strip_prefix and strip_suffix both exist in slice as well as str. Should I also implement slice::trim_prefix and slice::trim_suffix for consistency? (I could reopen the ACP or open a new one if that makes more sense.)

[Amanieu]

Yes, please implement these for slice as well. There is no need for another ACP.

[deven]

I submitted the pull request, but it appears I don't have the permissions to update the "S-tracking-unimplemented" label.