how to find the type of a supplied variable

[seany]

I have the following

void functionName(T)(T argumentVar)
{
    /+
    now i want that based on type of argumentVar, things will be 
done
    eg :
    if there is a function gettype; then :
    +/

    switch(argumentVar.gettype)
    {
        case "string array":
             //do something
        case "string":
             //treat srting as a file...
             //then do some other things
    }

}


How do I incorporrate this?