CChoiceFormat

CChoiceFormat is a helper that chooses an appropriate message based on the specified number value. The candidate messages are given as a string in the following format:

'expr1#message1|expr2#message2|expr3#message3'

where each expression should be a valid PHP expression with 'n' as the only variable. For example, 'n==1' and 'n%10==2 && n>10' are both valid expressions. The variable 'n' will take the given number value, and if an expression evaluates true, the corresponding message will be returned.

For example, given the candidate messages 'n==1#one|n==2#two|n>2#others' and the number value 2, the resulting message will be 'two'.

For expressions like 'n==1', we can also use a shortcut '1'. So the above example candidate messages can be simplified as '1#one|2#two|n>2#others'.

In case the given number doesn't select any message, the last candidate message will be returned.

The PHP expressions will be evaluated using evaluate.

protected static boolean evaluate(string $expression, mixed $n)

protected static function evaluate($expression,$n)
{
    try
    {
        return @eval("return $expression;");
    }
    catch (ParseError $e)
    {
        return false;
    }
}

public static string format(string $messages, mixed $number)

public static function format($messages, $number)
{
    $n=preg_match_all('/\s*([^#]*)\s*#([^\|]*)\|/',$messages.'|',$matches);
    if($n===0)
        return $messages;
    for($i=0;$i<$n;++$i)
    {
        $expression=$matches[1][$i];
        $message=$matches[2][$i];
        if($expression===(string)(int)$expression)
        {
            if($expression==$number)
                return $message;
        }
        elseif(self::evaluate(str_replace('n','$n',$expression),$number))
            return $message;
    }
    return $message; // return the last choice
}