You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
29 lines
753 B
29 lines
753 B
2 years ago
|
|
||
|
|
Exercise 3.37: The
|
||
|
|
celsius-fahrenheit-converter procedure is cumbersome when compared with
|
||
|
|
a more expression-oriented style of definition, such as
|
||
|
|
|
||
|
|
|
||
|
|
(define (celsius-fahrenheit-converter x)
|
||
|
|
(c+ (c* (c/ (cv 9) (cv 5))
|
||
|
|
x)
|
||
|
|
(cv 32)))
|
||
|
|
|
||
|
|
(define C (make-connector))
|
||
|
|
(define F (celsius-fahrenheit-converter C))
|
||
|
|
|
||
|
|
Here c+, c*, etc. are the “constraint” versions of the
|
||
|
|
arithmetic operations. For example, c+ takes two connectors as
|
||
|
|
arguments and returns a connector that is related to these by an adder
|
||
|
|
constraint:
|
||
|
|
|
||
|
|
|
||
|
|
(define (c+ x y)
|
||
|
|
(let ((z (make-connector)))
|
||
|
|
(adder x y z)
|
||
|
|
z))
|
||
|
|
|
||
|
|
Define analogous procedures c-, c*, c/, and cv
|
||
|
|
(constant value) that enable us to define compound constraints as in the
|
||
|
|
converter example above.161
|