Final End of Multi-methods • Fri 11:30 – 2:30 – Here • practice problems and sample final up on method equals(@Shape, @Shape):boolean { false } the web method equals(r1@Rect, r2@Rect) { ... } method equals(r1@Tri, r2@Tri) { ... } • Review session – some of it today, TA and I will hold special office hours next week for help In perl 6 In Java (called Multi-Java) class Test { class Shape { multi method what_is_it(Int $x) { public boolean equals(Shape@Shape) { return false } say "This is the integer $x"; } } multi method what_is_it(Str $s) { class Rect extends Shape { say "This is the string $s“; public boolean equals(Shape@Rect r) { ... } } } } class Circle extends Shape { my Test $t .= new(); public boolean equals(Shape@Circle c) { ... } $t.what_is_it(42); # This is the integer 42 } $t.what_is_it("weasel"); # This is the string weasel What’s on the final • Programming questions Short Review Session • In Ocaml • In Python • In Prolog • Other kinds of questions too… 1 What’s on the final (cont’d) Open book? • know how to … figure out ML types • No, but you may bring a cheat sheet • ... write decorators and python code • … write prolog predicates • know stuff about OO types (contra/covariant) • look at previous finals • test your solutions by hand Recap Functional • No mutation! Instead have environments Functional • Higher order programming (functions as params and returned values) • map and fold goodness • type system and type inference 2 Python • Dynamic dispatch Object Oriented • Inheritance • Decorators Constraint based programming • What do you think of Prolog? Prolog • Totally different model of computation • Way cool, if you ask me! • But can be hard to program in... What makes us like a language? What makes us like a language? • Type system? • Convenient shortcuts (Perl) ? • Simplicity? – at odds with convenient shortcuts • Orthogonality (language features don’t clash) – also at odds with convenient shortcuts • Libraries? (very important one) 3 Course Goals Course goals, achieved? “Free your mind” • What new things have you learned? -Morpheus You will learn several new - languages and constructs - ways to describe and organize computation Yes, you can do that in Java/Assembly but … Ok, that’s it folks • Did my best to try to teach you something new. • Hope this class was enjoyable, and that you learned something. 4.