Madlibs Iteration 11

madlibs_iteration_11.rkt

#lang at-exp racket

(require (for-syntax racket/match))

(define prompt-responses
  ; Hash's list must be of cons of key value pairs such as (cons adjective null)
  (make-hash (list )))

(define (ask prompt)
  (display prompt)
  (read-line))

(define (lookup-or-ask var prompt)
  ; Given variable & prompt, checks if we've recorded a response and prompts as needed. Returns stored/new response.
  (if (null? (hash-ref prompt-responses var null))
      (let ([response (ask prompt)])
                (hash-set! prompt-responses var response))
      null)
  (hash-ref prompt-responses var null))
   
(define-syntax (blank stx)
  (match (syntax->datum stx)
    [(list _ var prompt)
     (datum->syntax stx `(lookup-or-ask ,var ,prompt))]))

;; Story templates

(define-syntax (story-template stx)
  (match (syntax->datum stx)
    [(list _ story-name parts)
     (datum->syntax stx `(define (,(string->symbol story-name)) (string-join ,parts "")))]))

(story-template "tree-story" (list
                              "There once was a big " (blank "adjective" "Adjective: ")
                              " tree in the old forest of " (blank "location" "Location: ")
                              ". Yes that's right, in " (blank "location" "discard") "."))

(story-template "river-story" (list
                               "The " (blank "adjective" "Adjective: ") " " (blank "adjective2" "Adjective: ")
                               " river ran to the " (blank "adjective" "discard") " " (blank "adjective2" "discard")
                               " sea."))