Stop show with sound -- Keyboard shortcut: 'x'  Next slide in show -- Keyboard shortcut: 'n'  3 minutes, 45 secondsThe Order of Evaluation - slide 12 : 26

The eta rewrite rule
An eta conversion lifts certain function calls out of a lambda convolute

A function f, which only passes its parameters on to another function e, can be substituted by e

(lambda(x) (e x)) <=> e   provided that x is not free in the expression e
Legal conversion:
Expression

 Converted Expression

(lambda (x) (square x))
 
square
Illegal conversion:
Expression

 Converted Expression

(lambda(x) ((lambda(y) (f x y)) x))
 
(lambda(y) (f x y))