103 lines
3.1 KiB
Racket
103 lines
3.1 KiB
Racket
#lang scribble/doc
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@(require "mz.ss"
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scribble/core
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scribble/html-properties
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(for-label racket/help
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net/url
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racket/gui/base))
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@; Beware of this hard-wired link to the main doc page:
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@(define main-doc-page
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(hyperlink "../index.html"
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#:style (make-style
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"plainlink"
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(list
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(make-attributes
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`((onclick . ,(format "return GotoPLTRoot(\"~a\");" (version)))))))
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"main documentation page"))
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@title{Interactive Help}
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@note-init-lib[racket/help]
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@deftogether[(
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@defidform[help]
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@defform/none[#:literals (help) (help string ...)]
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@defform/none[#:literals (help) (help id)]
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@defform/none[#:literals (help) (help id #:from module-path)]
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@defform/none[#:literals (help) (help #:search datum ...)]
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)]{
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@emph{For general help, see the @|main-doc-page|.}
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The @scheme[help] form searches the documentation and opens a web
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browser (using the user's selected browser) to display the results.
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@margin-note{See @schememodname[net/sendurl] for information on how
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the user's browser is launched to display help information.}
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A simple @scheme[help] or @scheme[(help)] form opens the main
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documentation page.
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The @scheme[(help string ...)] form---using literal strings, as
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opposed to expressions that produce strings---performs a
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string-matching search. For example,
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@schemeblock[
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(help "web browser" "firefox")
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]
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searches the documentation index for references that include the
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phrase ``web browser'' or ``firefox.''
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A @scheme[(help id)] form looks for documentation specific to the
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current binding of @scheme[id]. For example,
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@schemeblock[
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(require net/url)
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(help url->string)
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]
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opens a web browser to show the documentation for @scheme[url->string]
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from the @schememodname[net/url] library.
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For the purposes of @scheme[help], a @scheme[for-label] require
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introduces a binding without actually executing the
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@schememodname[net/url] library---for cases when you want to check
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documentation, but cannot or do not want to run the providing module.
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@schemeblock[
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(require racket/gui) (code:comment @#,t{does not work in @exec{racket}})
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(require (for-label racket/gui)) (code:comment @#,t{ok in @exec{racket}})
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(help frame%)
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]
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If @scheme[id] has no for-label and normal binding, then @scheme[help]
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lists all libraries that are known to export a binding for
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@scheme[id].
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The @scheme[(help id #:from module-path)] variant is similar to
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@scheme[(help id)], but using only the exports of
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@scheme[module-path]. (The @scheme[module-path] module is required
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@scheme[for-label] in a temporary namespace.)
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@schemeblock[
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(help frame% #:from racket/gui) (code:comment @#,t{equivalent to the above})
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]
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The @scheme[(help #:search datum ...)] form is similar to
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@scheme[(help string ...)], where any non-string form of
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@scheme[datum] is converted to a string using @scheme[display]. No
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@scheme[datum] is evaluated as an expression.
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For example,
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@schemeblock[
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(help #:search "web browser" firefox)
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]
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also searches the documentation index for references that include the
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phrase ``web browser'' or ``firefox.''
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}
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