GetTok

function GetTok( string, separator, n, m = 0 ){
    //To support the old calculation, we need to do this.
    n = n - 1;
    m = m > 0 ? m : n + 1;
    local tokenized = split( string, separator ),
            text = "";
    if( n > tokenized.len() || n < 0 || m > tokenized.len() ) return null;
    tokenized = tokenized.slice( n, m );
    return tokenized.reduce( function( prev, next ){ return ( prev + separator + next ) } );
}

// THIS SCRIPT IS FOR TESTING THIS FUNCTION:

local test = "I'm a quick brown little fox.";
print( GetTok( test, " ", 1 ) );
print( GetTok( test, " ", 1, 6 ) );

// OUTPUT
/*
I'm
I'm a quick brown little fox.
*/