Module 4 Flashcards

Front 1

immutable

Back 1

an object who state cannot be modified after it is created

Front 2

function binding (syntax)

Back 2

fun x0 (x1 : t1, ..., xn : tn) = e;

where the function name is x0. It takes n arguments x1, ... xn of types t1, ..., tn and has an expression e for its body.

Front 3

function binding (type checking)

Back 3

fun x0 (x1 : t1, ..., xn : tn) = e;

for the function binding to type-check, the body e must have the type t, i.e. the result type of x0.

Front 4

function binding (evaluation)

Back 4

fun x0 (x1 : t1, ..., xn : tn) = e;

a function is a value- we simply add x0 to the environment as a function that can be called later.

Front 5

recursive

Back 5

a function definition can use itself.

Front 6

type inference

Back 6

figuring out types not written down

Front 7

function calls (syntax)

Back 7

The syntax is e0 (e1, ..., en) with the parentheses optional if there is exactly one argument.

Front 8

function calls (type checking)

Back 8

typing rules require that e0 has a type that looks like t1 * ... * tn -> t and for 1 ≤ i ≤ n, ei has type ti. Then the whole call has type t.

Front 9

function calls (evaluation)

Back 9

use the environment at the point of the call to evaluate e0 to v0, e1 to v1, ..., en to vn.