Qubit Case

Naming style detection and conversion helpers for Rust.

Overview

Qubit Case converts ASCII identifiers between common naming styles used by Java, C++, Python, XML, JSON, and Rust tooling through a compact Rust enum API.

Design Goals

• Small API surface: expose one core CaseStyle enum, five convenience constants, and focused parsing and validation errors.
• Consistent behavior: provide stable conversion results for supported ASCII identifier formats.
• Strict matching: validate whether a string conforms to a style.
• Best-effort conversion: convert inputs even when they are not strictly valid for the source style.
• No runtime dependencies: keep the library lightweight.

Supported Styles

• LOWER_HYPHEN: lower-hyphen
• LOWER_UNDERSCORE: lower_underscore
• LOWER_CAMEL: lowerCamel
• UPPER_CAMEL: UpperCamel
• UPPER_UNDERSCORE: UPPER_UNDERSCORE

Installation

Add this to your Cargo.toml:

[dependencies]
qubit-case = "0.2"

Quick Start

use qubit_case::{
    LOWER_CAMEL,
    LOWER_HYPHEN,
    UPPER_UNDERSCORE,
};

let value = LOWER_HYPHEN.to(LOWER_CAMEL, "hello-world");
assert_eq!(value, "helloWorld");

LOWER_CAMEL
    .validate("http2Client")
    .expect("the value should be lower camel case");

let constant = LOWER_CAMEL
    .checked_to(UPPER_UNDERSCORE, "http2Client")
    .expect("the source value should be valid");
assert_eq!(constant, "HTTP_2_CLIENT");

assert!(UPPER_UNDERSCORE.matches("HTTP_2_CLIENT"));
assert_eq!(LOWER_CAMEL.to_string(), "lower-camel");

API Reference

Types

• CaseStyle - supported case styles and conversion methods.
• CaseStyleError - error returned when parsing an unknown style name.
• CaseStyleValidationError - error returned when a value does not match the expected style.

Constants

• LOWER_HYPHEN
• LOWER_UNDERSCORE
• LOWER_CAMEL
• UPPER_CAMEL
• UPPER_UNDERSCORE

Methods

• CaseStyle::values() returns all styles in reference order.
• CaseStyle::of(name) parses a style name case-insensitively, treating hyphen and underscore as equivalent.
• CaseStyle::name() returns the canonical lower-hyphen style name.
• CaseStyle::word_separator() returns the style separator.
• CaseStyle::to(target, value) performs permissive best-effort conversion without validating the source or guaranteeing that invalid input matches the target style.
• CaseStyle::validate(value) validates an identifier and reports a mismatch.
• CaseStyle::checked_to(target, value) validates the source before converting it.
• CaseStyle::matches(value) checks whether an identifier strictly follows a style.

Trait Implementations

• Display formats a style using its canonical lower-hyphen name.
• FromStr parses the names accepted by CaseStyle::of.

Testing

# Run tests with the default feature set
cargo test

# Run tests with all declared features
cargo test --all-features

# Project CI checks
./ci-check.sh

# Check code coverage
./coverage.sh

License

Copyright (c) 2025 - 2026. Haixing Hu. All rights reserved.

Licensed under the Apache License, Version 2.0. See LICENSE for the full license text.

Contributing

Contributions are welcome. Please follow the Rust API guidelines, keep public API documentation and tests current, and run ./align-ci.sh to format code and ./ci-check.sh to satisfy CI requirements before submitting a pull request.

Author

Haixing Hu - Qubit Co. Ltd.

Repository: https://github.com/qubit-ltd/rs-case