package gls.ch03.s03/** * GLS 3.3: * Implementations first recognize Unicode escapes in their input, translating  * the ASCII characters backslash and 'u' followed by four hexadecimal digits * to the Unicode character with the indicated hexadecimal value, and passing * all other characters unchanged.   * * @author Alan Green */class UnicodeEscapes2 extends GroovyTestCase {    // GLS: If an even number of backslashes precede the 'u', it is not     // an escape    void testCountBackslash() {        def a = 1        assert \u0061 == 1 // char 61 is 'a'                // Not intepreted as an escape        // \\u0061 == 1 // @fail:parse        assert "\u0061".length() == 1        // Double backslash interpreted as a single backslash in string        assert "\\u0061".length() == 6        assert "\\\u0061".length() == 2            }    // GLS: If an eligible \ is followed by u, or more than one u, and the last u    // is not followed by four hexadecimal digits, then a compile-time error    // occurs.    void testFourHexDigits() {        // these next lines won't work. The backslash has been replace by a         // forwards slash so that the file parses. (Comments don't comment out        // unicode escapes.)        // assert "/u7" == "\07" //@fail:parse         // def /u61 = 2 //@fail:parse         // def /u061 = 2 //@fail:parse         // If five digits, only the first four count        def \u00610 = 2         assert a0 == 2    }    void testInvalidHexDigits() {        // invalid hex digits        // assert "\ufffg" == "a" // @fail:parse        // assert "\uu006g" == "a" // @fail:parse        // assert "\uab cd" == "acd" // @fail:parse    }}