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beautiful-racket/beautiful-racket/br/demo/txtadv/expander.rkt

330 lines
10 KiB
Racket

#lang br
(require (for-syntax racket/string))
(provide define-verbs
define-thing
define-place
define-everywhere
show-current-place
show-inventory
have-thing?
take-thing!
drop-thing!
thing-state
set-thing-state!
(except-out (all-from-out br) #%module-begin)
(rename-out [module-begin #%module-begin]))
;; ============================================================
;; Overall module:
(define #'(module-begin _lines ...)
#'(#%module-begin
_lines ...
(provide do-verb do-place)
(module+ main
(parameterize ([cmd-line-mode? #t])
(do-place)))))
(provide txtadv-program)
(define #'(txtadv-program _section ...)
#'(module-begin _section ...))
(provide verb-section)
(define-inverting #'(verb-section _heading _verb-item ...)
(inject-syntax ([#'in-verbs (shared-syntax 'in-verbs)])
#'(define-verbs in-verbs
_verb-item ...)))
(provide verb-item)
(define-inverting #'(verb-item (_name0 _transitive0?) (_name _transitive?) ... _desc)
#`[_name0 #,@(if (syntax->datum #'_transitive0?) #'(_) #'()) (= _name ...) _desc])
(provide verb-name)
(define-cases #'verb-name
;; cases with literals go first, so they're not caught by wildcards
[#'(_ "," _id) #'(_id #f)]
[#'(_ "," _id _underscore) #'(_id #t)]
[#'(_ _id) #'(_id #f)]
[#'(_ _id _underscore) #'(_id #t)])
(provide everywhere-section)
(define-inverting #'(everywhere-section _heading [_name _desc] ...)
#'(define-everywhere everywhere-actions
([_name _desc] ...)))
(provide id-desc)
(define-inverting #'(id-desc _id _desc)
#'(_id _desc))
(provide things-section)
(define-inverting #'(things-section _heading _thing ...)
#'(begin _thing ...))
(provide thing-item)
(define-inverting #'(thing-item _thingname (_actionname _actiondesc) ...)
#'(define-thing _thingname [_actionname _actiondesc] ...))
(provide places-section)
(define-inverting #'(places-section _heading _placeitem ...)
#'(begin _placeitem ...))
(provide place-item)
(define-inverting #'(place-item _place-id _place-desc [_place-item ...] [_actionname _actiondesc] ...)
#'(define-place _place-id _place-desc [_place-item ...] ([_actionname _actiondesc] ...)))
(provide place-descrip)
(define #'(place-descrip _desc) #'_desc)
(provide place-items)
(define-inverting #'(place-items "[" _id ... "]") #'(_id ...))
(provide place-name)
(define-cases #'place-name
[#'(_ "," _id) #'_id]
[#'(_ _id) #'_id])
(provide s-exp)
(define-cases-inverting #'s-exp
[#'(_ "(" _sx ... ")") #'(_sx ...)]
[#'(_ _sx) #'_sx])
;; todo: consolidate the game-starters.
;; `start-game-at` works with s-exp language,
;; `start-section` works with text lang.
(provide start-game-at)
(define #'(start-game-at _where)
(inject-syntax ([#'in-verbs (shared-syntax 'in-verbs)])
#'(init-game _where
in-verbs
everywhere-actions)))
(provide start-section)
(define #'(start-section _heading _where)
(inject-syntax ([#'in-verbs (shared-syntax 'in-verbs)])
#'(init-game _where
in-verbs
everywhere-actions)))
;; ============================================================
;; Model:
;; Elements of the world:
(struct verb (aliases ; list of symbols
desc ; string
transitive?) #:transparent) ; boolean
(struct thing (name ; symbol
[state #:mutable] ; any value
actions) #:transparent) ; list of verb--thunk pairs
(struct place (desc ; string
[things #:mutable] ; list of things
actions) #:transparent) ; list of verb--thunk pairs
(define action-verb car)
(define action-response cdr)
;; Tables mapping names<->things for save and load
(define names (make-hash))
(define elements (make-hash))
(define (record-element! name val)
(hash-set! names name val)
(hash-set! elements val name))
(define (name->element name) (hash-ref names name #f))
(define (element->name obj) (hash-ref elements obj #f))
;; ============================================================
;; Macros for constructing and registering elements:
(define #'(define-verbs _all-id [_id _spec ...] ...)
#'(begin
(define-one-verb _id _spec ...) ...
(record-element! '_id _id) ...
(define _all-id (list _id ...))))
;; todo: the underscore arguments in cases 2 & 4 should be literal underscores, not wildcards
(define-cases #'define-one-verb
[#'(_ _id (= _alias ...) _desc)
#'(define _id (verb (list '_id '_alias ...) _desc #f))]
[#'(_ _id _ (= _alias ...) _desc)
#'(define _id (verb (list '_id '_alias ...) _desc #t))]
[#'(_ _id)
#'(define _id (verb (list '_id) (symbol->string '_id) #f))]
[#'(_ _id _)
#'(define _id (verb (list '_id) (symbol->string '_id) #t))])
(define #'(define-thing _id [_vrb _expr] ...)
#'(begin
(define _id
(thing '_id #f (list (cons _vrb (λ () _expr)) ...)))
(record-element! '_id _id)))
(define #'(define-place _id _desc (_thng ...) ([_vrb _expr] ...))
#'(begin
(define _id (place _desc
(list _thng ...)
(list (cons _vrb (λ () _expr)) ...)))
(record-element! '_id _id)))
(define #'(define-everywhere _id ([_vrb _expr] ...))
#'(define _id (list (cons _vrb (λ () _expr)) ...)))
;; ============================================================
;; Game state
(define cmd-line-mode? (make-parameter #f))
;; Initialized on startup:
(define game-verbs null) ; list of verbs
(define everywhere-actions null) ; list of verb--thunk pairs
;; Things carried by the player:
(define player-inventory null) ; list of things
;; Current location:
(define current-place #f) ; place (or #f until started)
;; Fuctions to be used by verb responses:
(define (have-thing? thing)
(memq thing player-inventory))
(define (take-thing! thing)
(set-place-things! current-place (remq thing (place-things current-place)))
(set! player-inventory (cons thing player-inventory)))
(define (drop-thing! thing)
(set-place-things! current-place (cons thing (place-things current-place)))
(set! player-inventory (remq thing player-inventory)))
;; ============================================================
;; Game execution
;; Show the player the current place, then get a command:
(define (do-place)
(show-current-place)
(when (cmd-line-mode?) (do-verb)))
;; Show the current place:
(define (show-current-place)
(printf "~a\n" (place-desc current-place))
(for-each
(λ (thing) (printf "There is a ~a here.\n" (thing-name thing)))
(place-things current-place)))
;; Get and handle a command:
(define (get-line)
(printf "> ")
(flush-output)
(read-line))
(define (do-verb [line (and (cmd-line-mode?) (get-line))])
(define input (if (eof-object? line)
'(quit)
(let ([port (open-input-string line)])
(for/list ([v (in-port read port)]) v))))
(if (and (list? input)
(andmap symbol? input)
(<= 1 (length input) 2))
(let* ([verb (car input)]
[response
(cond
[(= 2 (length input))
(handle-transitive-verb verb (cadr input))]
[(= 1 (length input))
(handle-intransitive-verb verb)])]
[result (response)])
(cond
[(place? result)
(set! current-place result)
(do-place)]
[(string? result)
(printf "~a\n" result)
(when (cmd-line-mode?) (do-verb))]
[else (when (cmd-line-mode?) (do-verb))]))
(begin
(printf "I don't undertand what you mean.\n")
(when (cmd-line-mode?) (do-verb)))))
;; Handle an intransitive-verb command:
(define (handle-intransitive-verb verb)
(or
(find-verb verb (place-actions current-place))
(find-verb verb everywhere-actions)
(using-verb
verb game-verbs
(λ (verb)
(λ () (if (verb-transitive? verb)
(format "~a what?" (string-titlecase (verb-desc verb)))
(format "Can't ~a here." (verb-desc verb))))))
(λ () (format "I don't know how to ~a." verb))))
;; Handle a transitive-verb command:
(define (handle-transitive-verb verb-in obj)
(or (using-verb
verb-in game-verbs
(λ (verb)
(and
(verb-transitive? verb)
(cond
[(ormap (λ (thing)
(and (eq? (thing-name thing) obj)
thing))
(append (place-things current-place)
player-inventory))
=> (λ (thing)
(or (find-verb verb-in (thing-actions thing))
(λ ()
(format "Don't know how to ~a ~a."
(verb-desc verb) obj))))]
[else
(λ () (format "There's no ~a here to ~a." obj
(verb-desc verb)))]))))
(λ () (format "I don't know how to ~a ~a." verb-in obj))))
;; Show what the player is carrying:
(define (show-inventory)
(printf "You have")
(if (null? player-inventory)
(printf " no items.")
(for-each (λ (thing)
(printf "\n a ~a" (thing-name thing)))
player-inventory))
(printf "\n"))
;; Look for a command match in a list of verb--response pairs,
;; and returns the response thunk if a match is found:
(define (find-verb cmd actions)
(for/first ([action (in-list actions)]
#:when (memq cmd (verb-aliases (action-verb action))))
(action-response action)))
;; Looks for a command in a list of verbs, and
;; applies `success-func' to the verb if one is found:
(define (using-verb cmd verbs success-func)
(for/first ([verb (in-list verbs)]
#:when (memq cmd (verb-aliases verb)))
(success-func verb)))
;; ============================================================
;; To go:
(define (init-game in-place
in-verbs
in-everywhere-actions)
(set! current-place in-place)
(set! game-verbs in-verbs)
(set! everywhere-actions in-everywhere-actions))