gistfile1.rkt

#lang racket

(provide daddy-brings-worms
         momma-sits)

(module nest racket  
  (provide eggs chicks lay-egg hatch)
  (define eggs 0)
  (define chicks 0)
  (define (hatch)
    (if (> eggs 0)
        (begin
          (set! eggs (sub1 eggs))
          (set! chicks (add1 chicks)))
        (void)))        
  (define (lay-egg)
    (set! eggs (add1 eggs))))

(module birds racket
  
  (provide
   daddy-brings-worms
   momma-sits)  
  
  (require 
   (for-syntax syntax/parse)
   (for-meta 1 (submod ".." nest)))
  
  (define-syntax (daddy-brings-worms stx)
    (syntax-parse stx
      [(_) 
       (lay-egg)
       (with-syntax ((nest-state (cons eggs chicks)))             
         #''nest-state)]))
  
  (define-syntax (momma-sits stx)
    (syntax-parse stx
      [(_) 
       (hatch)
       (with-syntax ((nest-state (cons eggs chicks)))             
         #''nest-state)]))
    
  )

(require (submod "." birds))

(define the-nest
  (begin
    (daddy-brings-worms)
    (momma-sits)
    (daddy-brings-worms)))

the-nest