Tracking Issue for `const` `str::split_at*`

[zachs18]

Feature gate: #![feature(const_str_split_at)]

This is a tracking issue for using str::split_at, str::split_at_mut, str::split_at_checked, str::split_at_mut_checked in const, which allows dividing one (mutable) string slice into two (fallibly) at an index during const-eval.

Public API

// core::str
impl str {
    pub const fn split_at(&self, mid: usize) -> (&str, &str);
    pub const fn split_at_mut(&mut self, mid: usize) -> (&mut str, &mut str);
    pub const fn split_at_checked(&self, mid: usize) -> Option<(&str, &str)>;
    pub const fn split_at_mut_checked(&mut self, mid: usize) -> Option<(&mut str, &mut str)>;
}

Steps / History

• Implementation: Mark str::is_char_boundary and str::split_at* unstably const. #131520
• Blocked on Tracking Issue for const_is_char_boundary #131516
• Final comment period (FCP)¹: Stabilize const_is_char_boundary and const_str_split_at. #134016 (comment)
• Stabilization PR: Stabilize const_is_char_boundary and const_str_split_at. #134016

Unresolved Questions

• None yet.

Footnotes

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