SMAL for ML Programming - Lab 2005 | CECS 424, Lab Reports of Computer Science

Download SMAL for ML Programming - Lab 2005 | CECS 424 and more Lab Reports Computer Science in PDF only on Docsity! CECS 424 Lab on 9/13/05 Do the following: 1. Start SML for ML programming. 2. Learn to program with patterns in ML. Type each of the following lines and see what happens: a) Simple Patterns fun f _ = “yes”; (* _ is a pattern that matches anything *) f 34.5; (* use the above function *) f []; f (1, 2, 3); fun f x = “yes”; (* an alternative way of defining f that introduces an unused variable *) f 34.5; (* use the above function *) f []; f (1, 2, 3); fun f 0 = “yes”; (* pattern is a constant *) f 0; f 1; b) Complex Patterns fun f [a, _] = a; (* pattern is a list of exactly 2 items *) f [ #”H”, #”K”]; f [ #”H” ]; f ( #”H”, #”K” ); fun f (x::xs) = x; (* pattern is any non-empty list *) f [1, 2, 3]; f [ #”H”, #”K”]; f [ #”H” ]; f ( #”H”, #”K” ); c) Multiple Patterns fun f 0 = “zero” | f 1 = “one”; f 0; f 1; f 2; fun f 0 = “zero” | f _ = “non-zero”; f 0; f 2; f (2); f (1, 2); f [1, 2]; fun f n = if n = 0 then “zero” else “non-zero”; (* an alternative definition using a variable *) f 0; f 2; f (2); f (1, 2); f [1, 2];