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 = "0.1"

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 & Code Coverage

This project tests successful and checked conversions, validation errors, style parsing and display, style matching, CamelCase acronym boundaries, digit boundaries, empty input, Unicode safety, and best-effort conversion behavior.

Running Tests

# Run all tests
cargo test

# Run with coverage report
./coverage.sh

# Generate text format report
./coverage.sh text

# Run CI checks (format, clippy, test, coverage, audit)
./ci-check.sh

Coverage Metrics

See COVERAGE.md for detailed coverage statistics.

Dependencies

This crate has no runtime dependencies.

License

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

See LICENSE for the full license text.

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

Development Guidelines

Follow the Rust API guidelines.
Maintain comprehensive test coverage.
Document all public APIs with examples when they clarify usage.
Run ./ci-check.sh before submitting PRs.

Author

Haixing Hu

Related Projects

More Rust libraries from Qubit are published under the qubit-ltd organization on GitHub.

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

qubit-case 0.2.0