Created: Sun Nov 25 14:58:41 CET 2018

Last modiﬁed: Thu Dec 27 09:40:43 CET 2018

Scheme is

*lexically scoped*Names deﬁned in

`let`

are*let-bound*`(x y)`

in`(lambda (x y) body)`

is the list of the*formal parameters*`x`

*occurs free*in`(lambda () x)`

`x`

is a*free variable*in`(lambda () x)`

`1`

and`2`

are the*actual parameters*in`((lambda (x y) (+ x y)) 1 2)`

`1`

and`2`

are the*arguments values*in`((lambda (x y) (+ x y)) 1 2)`

*actual parameters*are bound to the*formal parameters*before evaluation of the body`set!`

is used to perform an*assignment*an object whose behavior is not known operationnaly is called an

*abstract*object