tools/aconfig/src/codegen.rs

/*
 * Copyright (C) 2023 The Android Open Source Project
 *
 * 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.
 */

pub fn is_valid_identifier(s: &str) -> bool {
    // Identifiers must match [a-z][a-z0-9_]*
    let mut chars = s.chars();
    let Some(first) = chars.next() else {
        return false;
    };
    if !first.is_ascii_lowercase() {
        return false;
    }
    chars.all(|ch| ch.is_ascii_lowercase() || ch.is_ascii_digit() || ch == '_')
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_is_valid_identifier() {
        assert!(is_valid_identifier("foo"));
        assert!(is_valid_identifier("foo_bar_123"));

        assert!(!is_valid_identifier(""));
        assert!(!is_valid_identifier("123_foo"));
        assert!(!is_valid_identifier("foo-bar"));
        assert!(!is_valid_identifier("foo-b\u{00e5}r"));
    }
}