roe

Implements Unicode case mapping for conventionally UTF-8 binary strings.

Case mapping or case conversion is a process whereby strings are converted to
a particular form—uppercase, lowercase, or titlecase—possibly for display to
the user.

roe can convert conventionally UTF-8 binary strings to capitalized, lowercase,
and uppercase forms. This crate is used to implement String#capitalize,
Symbol#capitalize, String#downcase, Symbol#downcase,
String#upcase, and Symbol#upcase in Artichoke Ruby.

This crate depends on bstr.

Implementation

Roe generates conversion tables from Unicode Data Files. Roe implements case
mapping as defined in the Unicode standard (see PropList.txt,
SpecialCasing.txt, UnicodeData.txt).

Status

This crate is currently a work in progress. When the API is complete, Roe will
support lowercase, uppercase, titlecase, and case folding iterators for
conventionally UTF-8 byte slices.

Roe will implement support for full, Turkic, ASCII, and case folding transforms.

Usage

Add this to your Cargo.toml:

[dependencies]
roe = "0.0.7"

Then convert case like:

use roe::{LowercaseMode, UppercaseMode, TitlecaseMode};

assert_eq!(
    roe::lowercase(b"Artichoke Ruby", LowercaseMode::Ascii).collect::<Vec<_>>(),
    b"artichoke ruby"
);
assert_eq!(
    roe::uppercase("Αύριο".as_bytes(), UppercaseMode::Full).collect::<Vec<_>>(),
    "ΑΎΡΙΟ".as_bytes()
);
assert_eq!(
    roe::titlecase("ffi".as_bytes(), TitlecaseMode::Full).collect::<Vec<_>>(),
    "Ffi".as_bytes()
);

Crate Features

roe is no_std compatible with an optional dependency on the alloc crate.

roe has several Cargo features, all of which are enabled by default:

• std - Adds a dependency on std, the Rust Standard Library. This
  feature enables std::error::Error implementations on error types in this
  crate. Enabling the std feature also enables the alloc feature.
• alloc - Adds a dependency on alloc, the Rust allocation and
  collections library. This feature enables APIs that allocate String or
  Vec.

Unicode Version

Roe implements Unicode case mapping with the Unicode 16.0.0 case mapping
ruleset.

Each new release of Unicode may bring updates to the Data Files which are the
source for the case mappings in this crate. Updates to the case mapping rules
will be accompanied with a minor version bump.

License

roe is licensed under the MIT License (c) Ryan Lopopolo.

roe includes Unicode Data Files which are subject to the Unicode Terms of
Use and Unicode License v3 (c) 1991-2024 Unicode, Inc.