Version Number Semantic Java Example

// version number semantic java example - JavaScript
const regex = /^[a-zA-Z_$][a-zA-Z0-9_$]*$/;

function validate(input) {
  if (!input || typeof input !== 'string') return false;
  return regex.test(input.trim());
}

// Usage examples
console.log(validate('variableName')); // true
console.log(validate('123var')); // false

# version number semantic java example - Python
import re

pattern = r"^[a-zA-Z_$][a-zA-Z0-9_$]*$"
regex = re.compile(pattern)

def validate(input_str):
    if not input_str or not isinstance(input_str, str):
        return False
    return bool(regex.match(input_str.strip()))

# Usage examples
print(validate('variableName'))  # True
print(validate('123var'))  # False

<?php
// version number semantic java example - PHP
function validate($input) {
    if (!is_string($input) || empty(trim($input))) {
        return false;
    }
    
    $pattern = '/^[a-zA-Z_$][a-zA-Z0-9_$]*$/';
    return preg_match($pattern, trim($input)) === 1;
}

// Usage examples
var_dump(validate('variableName')); // bool(true)
var_dump(validate('123var')); // bool(false)
?>

// Version Number Semantic Java Example - Java
import java.util.regex.Pattern;

public class RegexValidator {
    private static final Pattern pattern = Pattern.compile("^[a-zA-Z_$][a-zA-Z0-9_$]*$");
    
    public static boolean validate(String input) {
        if (input == null || input.trim().isEmpty()) {
            return false;
        }
        return pattern.matcher(input.trim()).find();
    }
    
    // Usage examples
    public static void main(String[] args) {
        System.out.println(validate("test-input")); // Check pattern match
    }
}