Play audio slide show -- Keyboard shortcut: 'x'  Lecture overview -- Keyboard shortcut: 'u'  Previous page: Delayed evaluation and infinite lists in Scheme [Section] -- Keyboard shortcut: 'p'  Next page: Examples of delayed evaluation -- Keyboard shortcut: 'n'  Lecture notes - all slides together  Annotated slide -- Keyboard shortcut: 't'  Textbook -- Keyboard shortcut: 'v'  Alphabetic index  Help page about these notes  Course home      The Order of Evaluation - slide 21 : 26

Delayed evaluation in Scheme
Scheme does not support normal-order reduction nor lazy evaluation

Scheme has an explicit primitive which delays an evaluation

(delay expr) => promise
(force promise) => value
A principled implementation of delay and force in Scheme.
Real implementations of delay.