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# Description Add an extension trait `IgnoreCaseExt` to nu_utils which adds some case insensitivity helpers, and use them throughout nu to improve the handling of case insensitivity. Proper case folding is done via unicase, which is already a dependency via mime_guess from nu-command. In actuality a lot of code still does `to_lowercase`, because unicase only provides immediate comparison and doesn't expose a `to_folded_case` yet. And since we do a lot of `contains`/`starts_with`/`ends_with`, it's not sufficient to just have `eq_ignore_case`. But if we get access in the future, this makes us ready to use it with a change in one place. Plus, it's clearer what the purpose is at the call site to call `to_folded_case` instead of `to_lowercase` if it's exclusively for the purpose of case insensitive comparison, even if it just does `to_lowercase` still. # User-Facing Changes - Some commands that were supposed to be case insensitive remained only insensitive to ASCII case (a-z), and now are case insensitive w.r.t. non-ASCII characters as well. # Tests + Formatting - 🟢 `toolkit fmt` - 🟢 `toolkit clippy` - 🟢 `toolkit test` - 🟢 `toolkit test stdlib` --------- Co-authored-by: Stefan Holderbach <sholderbach@users.noreply.github.com>
56 lines
2.4 KiB
Rust
56 lines
2.4 KiB
Rust
use std::cmp::Ordering;
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use unicase::UniCase;
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pub trait IgnoreCaseExt {
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/// Returns a [case folded] equivalent of this string, as a new String.
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///
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/// Case folding is primarily based on lowercase mapping, but includes
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/// additional changes to the source text to help make case folding
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/// language-invariant and consistent. Case folded text should be used
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/// solely for processing and generally should not be stored or displayed.
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///
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/// Note: this method might only do [`str::to_lowercase`] instead of a
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/// full case fold, depending on how Nu is compiled. You should still
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/// prefer using this method for generating case-insensitive strings,
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/// though, as it expresses intent much better than `to_lowercase`.
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///
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/// [case folded]: <https://unicode.org/faq/casemap_charprop.html#2>
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fn to_folded_case(&self) -> String;
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/// Checks that two strings are a case-insensitive match.
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///
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/// Essentially `to_folded_case(a) == to_folded_case(b)`, but without
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/// allocating and copying string temporaries. Because case folding involves
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/// Unicode table lookups, it can sometimes be more efficient to use
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/// `to_folded_case` to case fold once and then compare those strings.
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fn eq_ignore_case(&self, other: &str) -> bool;
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/// Compares two strings case-insensitively.
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///
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/// Essentially `to_folded_case(a) == to_folded_case(b)`, but without
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/// allocating and copying string temporaries. Because case folding involves
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/// Unicode table lookups, it can sometimes be more efficient to use
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/// `to_folded_case` to case fold once and then compare those strings.
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///
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/// Note that this *only* ignores case, comparing the folded strings without
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/// any other collation data or locale, so the sort order may be surprising
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/// outside of ASCII characters.
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fn cmp_ignore_case(&self, other: &str) -> Ordering;
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}
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impl IgnoreCaseExt for str {
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fn to_folded_case(&self) -> String {
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// we only do to_lowercase, as unicase doesn't expose its case fold yet
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// (seanmonstar/unicase#61) and we don't want to pull in another table
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self.to_lowercase()
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}
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fn eq_ignore_case(&self, other: &str) -> bool {
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UniCase::new(self) == UniCase::new(other)
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}
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fn cmp_ignore_case(&self, other: &str) -> Ordering {
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UniCase::new(self).cmp(&UniCase::new(other))
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}
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}
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