chickadee » sicp » with-require

Installs require, an-element-of, an-integer-starting-from in the environment in addition to the primitive procedures enumerated in procedures; then calls receive-env with the configured environment.

procedures

A key-value list of primitive procedure-names and their definitions

receive-env

A lambda of one value that is called with the prepared environment

(define (with-require procedures receive-env)
  (with-primitive-procedures
    (append procedures `((member ,member) (not ,not)))
    (lambda (env)
      (ambeval* '(define (require p) (if (not p) (amb) 'success)) env)
      (ambeval*
        '(define (an-element-of items)
           (require (not (null? items)))
           (amb (car items) (an-element-of (cdr items))))
        env)
      (ambeval*
        '(define (an-integer-starting-from n)
           (amb n (an-integer-starting-from (+ n 1))))
        env)
      (ambeval*
        '(define (distinct? items)
           (cond ((null? items) true)
                 ((null? (cdr items)) true)
                 ((member (car items) (cdr items)) false)
                 (else (distinct? (cdr items)))))
        env)
      (receive-env env))))