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added world? and universe? docs

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svn: r15181
This commit is contained in:
Matthias Felleisen 2009-06-15 21:47:32 +00:00
parent 233df48709
commit a6e3bc1d41
1 changed files with 32 additions and 13 deletions
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45
collects/teachpack/2htdp/scribblings/universe.scrbl
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@ -161,8 +161,7 @@ The design of a world program demands that you come up with a data
@defform/subs[#:id big-bang
#:literals
(on-tick on-draw on-key on-mouse on-receive
stop-when register record? name)
(on-tick on-draw on-key on-mouse on-receive stop-when world? register record? name)
(big-bang state-expr clause ...)
([clause
(on-tick tick-expr)
@ -172,6 +171,7 @@ The design of a world program demands that you come up with a data
(on-draw draw-expr)
(on-draw draw-expr width-expr height-expr)
(stop-when stop-expr)
(world? world?-expr)
(record? boolean-expr)
(on-receive rec-expr)
(register IP-expr)
@ -417,6 +417,16 @@ All @tech{MouseEvent}s are represented via strings:
@item{
@defform[(world? world-expr?)
#:contracts
([world-expr? (-> Any boolean?)])]{
tell DrScheme to call the @scheme[world-expr?] function on the result of
every world handler call. If this call produces @scheme[true], the result
is considered a world; otherwise the world program signals an error.
}}
@item{
@defform[(record? boolean-expr)
#:contracts
([boolean-expr boolean?])]{
@ -1060,7 +1070,7 @@ The @tech{server} itself is created with a description that includes the
@defform/subs[#:id universe
#:literals
(on-new on-msg on-tick on-disconnect to-string)
(on-new on-msg on-tick on-disconnect to-string universe?)
(universe state-expr clause ...)
([clause
(on-new new-expr)
@ -1069,6 +1079,7 @@ The @tech{server} itself is created with a description that includes the
(on-tick tick-expr rate-expr)
(on-disconnect dis-expr)
(to-string render-expr)
(universe? universe?-expr)
])]{
creates a server with a given state, @scheme[state-expr]. The
@ -1169,6 +1180,14 @@ optional handlers:
}
}
@item{
@defform[(universe? universe?-expr)
#:contracts
([universe?-expr (-> Any boolean?)])]{
ensure that what the event handlers produce is really an element of
@tech{UniverseState}.}
}
]
@; -----------------------------------------------------------------------------
@ -1293,14 +1312,14 @@ translates into the design of two functions with the following headers,
;; (make-bundle UniverseState [Listof mail?] [Listof iworld?])
;; UniverseState iworld? -> Bundle
;; next list of worlds when world w is joining
;; the universe in state s
(define (add-world s w) ...)
;; next list of worlds when world @scheme[iw] is joining
;; the universe in state @scheme[s]
(define (add-world s iw) ...)
;; UniverseState iworld? W2U -> Bundle
;; next list of worlds when world w is sending message m to
;; the universe in state s
(define (process s p m) ...)
;; next list of worlds when world @scheme[iw] is sending message @scheme[m] to
;; the universe in state @scheme[s]
(define (process s iw m) ...)
))
Finally, we must also decide how the messages affect the states of the
@ -1418,12 +1437,12 @@ The preceding subsection dictates that our server program starts like this:
;; (make-bundle [Listof iworld?] (list (make-mail iworld? GoMessage)) '())
;; [Listof iworld?] iworld? -> Result
;; add world w to the universe, when server is in state u
(define (add-world u w) ...)
;; add world @scheme[iw] to the universe, when server is in state @scheme[u]
(define (add-world u @scheme[iw]) ...)
;; [Listof iworld?] iworld? StopMessage -> Result
;; world w sent message m when server is in state u
(define (switch u w m) ...)
;; world @scheme[iw] sent message @scheme[m] when server is in state @scheme[u]
(define (switch u iw m) ...)
])
Although we could have re-used the generic contracts from this