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svn: r12762
This commit is contained in:
Jay McCarthy 2008-12-10 16:37:18 +00:00
parent 004759505b
commit 247d9fb5fe
1 changed files with 32 additions and 4 deletions
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36
collects/web-server/scribblings/web.scrbl
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@ -52,10 +52,18 @@ functions of interest for the servlet developer.
@defproc[(send/suspend/dispatch [make-response (embed/url/c . -> . response?)]) @defproc[(send/suspend/dispatch [make-response (embed/url/c . -> . response?)])
any/c]{ any/c]{
Calls @scheme[make-response] with a function that, when called with a procedure from Calls @scheme[make-response] with a function (@scheme[embed/url]) that, when called with a procedure from
@scheme[request?] to @scheme[any/c] will generate a URL, that when invoked will call @scheme[request?] to @scheme[any/c] will generate a URL, that when invoked will call
the function with the @scheme[request?] object and return the result to the caller of the function with the @scheme[request?] object and return the result to the caller of
@scheme[send/suspend/dispatch]. @scheme[send/suspend/dispatch]. Therefore, if you pass @scheme[embed/url] the identity function,
@scheme[send/suspend/dispatch] devolves into @scheme[send/suspend]:
@schemeblock[
(define (send/suspend response-generator)
(send/suspend/dispatch
(lambda (embed/url)
(response-generator (embed/url (lambda (x) x))))))
]
Use @scheme[send/suspend/dispatch] when there are multiple `logical' continuations of a page. Use @scheme[send/suspend/dispatch] when there are multiple `logical' continuations of a page.
For example, we could either add to a number or subtract from it: For example, we could either add to a number or subtract from it:
@ -79,8 +87,28 @@ functions of interest for the servlet developer.
(add1 i)))]) (add1 i)))])
"+")))))))) "+"))))))))
] ]
It is very common that the return value of @scheme[send/suspend/dispatch] is irrevelant in Notice that in this example the result of the handlers are returned to the continuation of @scheme[send/suspend/dispatch].
your application and you may think of it as ``embedding'' value-less callbacks. However, it is very common that the return value of @scheme[send/suspend/dispatch] is irrevelant in
your application and you may think of it as ``embedding'' value-less callbacks. Here is the same example in this style:
@schemeblock[
(define (count-dot-com i)
(send/suspend/dispatch
(lambda (embed/url)
`(html
(head (title "Count!"))
(body
(h2 (a ([href
,(embed/url
(lambda (req)
(count-dot-com (sub1 i))))])
"-"))
(h1 ,(number->string i))
(h2 (a ([href
,(embed/url
(lambda (req)
(count-dot-com (add1 i))))])
"+")))))))
]
} }
@defproc[(send/forward [make-response response-generator/c] @defproc[(send/forward [make-response response-generator/c]