Types

Front 1

strongly typed language

Back 1

always detects type errors

Front 2

weakly typed language

Back 2

"anything can go"

Front 3

three views of types

Back 3

1. denotation: a type is a set of values

2. constructive: built-in or composite(made up of different parts)

3. abstraction-based: a type is a set of values and operations on them

Front 4

example of denotation view of type

Back 4

enum colorType {red, blue, green};

struct Object {int object; colorType color};

Front 5

example of constructive view of type

Back 5

built-in: char, int, float, boolean

composite: records/structs, arrays, classes, lists/sets

Front 6

type orthogonality

Back 6

different constructs can be combined in any combination

i.e array of object of arbitrary types

Front 7

Two types of type equivalence

Back 7

Structural - same components put together in same way. (type1{char a, int b} == type2{char a, int b}!=type3{int b, char a})

Name or Declarative - have the "same" name

c_temp = float; and f_temp = float;

Front 8

infer type i for (i + 1) if 1 is an int

Back 8

type(i) = int