Call-by-name vs call-by-value in Scala

gistfile1.scala

/* call-by-value means the parameters are evaluated left to 
** right to determine their value before the function itself 
** is evaluated 
*/
def first(a: Int, b: Int): Int = a
first(3 + 4, 5 + 6) // will be reduced to first(7, 5 + 6), then first(7, 11), and then 7

/* call-by-name means the paramter is passed into the function 
** as is. Parameter evaluation takes place after 
** substitution 
*/
def first1(a: Int, b: => Int): Int = a
first1(3 + 4, 5 + 6) // will be reduced to (3 + 4) and then to 7