Kotlin regex condition

kotlin_regex_condition.kt

val scripts = listOf(
"""  
  if (1 != 0) {
    document.writeln('valid');
  }else{
    document.writeln('invalid');  };
  </script>""",
                     
"""  
  if (0 != 0) {
    document.writeln('valid');
  }else{
    document.writeln('invalid');  };
  </script>""",
                     
"""xxx""")

fun main() {
    val regex = Regex("""if \((\d+) != 0\)""")
    
    scripts.zip(listOf(true, false, false)){script, expected -> 
        // the straightforward way
        val mr = regex.find(script)
        var isValid = if (mr != null) mr.groupValues[1] != "0" else false
        assert(isValid == expected)

        // this also works but seems less clear
        isValid = mr?.groupValues?.get(1) ?: "0" != "0"
        assert(isValid == expected)

        // without intermediate variable
        isValid = regex.find(script)?.run{ groupValues[1] != "0" } ?: false
        assert(isValid == expected)
    }
}