Thunks and Streams Assignment

Thunk Utilities

define a function thunk? which returns #t if the specified parameter is a thunk, #f otherwise.

define a macro thunk which creates thunk

define a function dethunk which takes a thunk parameter th and returns the result of invoking th.

Stream Utilities

define a function plausible-stream? which returns #t if the specified parameter is a thunk which when invoked returns a pair whose cdr is a thunk, #f otherwise.

WARNING: what could happen if you called plausible-stream? recursively on the cdr?

define a function next-value-from-stream which takes a stream parameter and returns the next value of that stream.

define a function next-stream-from-stream which takes a stream parameter and returns the next stream of that stream.

define a function stream-cons which takes two parameters value and stream-prime. if the specified stream-prime parameter is not a thunk then an error should be raised:

(raise (error "not a thunk" stream-prime))

WARNING: what could happen if you called plausible-stream? on stream-prime?

Stream App

define flip-flop-stream which produces #t #f #t #f #t #f #t #f...