CSC151 2007S, Class 09: Boolean Values and Predicates

Admin:
* Are there questions on Homework 5?
  * Sorry for the confusion.
  * Don't worry about newlines/carriage returns
* Reading for Tuesday: Conditionals.

Overview:
* Preparation.
* Lab.

/Lab Notes/

* A good idea from BZ

(define table-column
  (lambda (val)
    (list 'number? (number? val)
          'symbol? (symbol? val)
          'string? (string? val)
	  'procedure? (procedure? val)
	  'boolean? (boolean? val)
	  'list? (list? val))))

* Math-geek question: (triangle? 1 2 3)
  Degenerate triangle

* primitive? is a built-in procedure that checks whether its parameter
  is a built-in procedure

* Another way to check ranges
  (define valid-grade?
    (lambda (grade)
      (<= 0 grade 100)))