16.3 Interactive Help
The bindings documented in this section are provided by the scheme/help and scheme/init libraries, which means that they ara available when mzscheme is started with no command-line arguments. They are not provided by scheme/base or scheme.
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Searches the documentation, and opens a web browser (using the user’s selected browser) to display the results. See net/sendurl for information on how the user’s browser is launched.
A simple help or (help) form opens this page.
A (help id) form looks for documentation specific to the current binding of id. For example,
(require net/url) |
opens a web browser to show the documentation for url->string from the net/url library.
For the purposes of help, a for-label require introduces a binding without actually executing the net/url library – for cases when you want to check documentation, but cannot or do not want to run the providing module.
(require scheme/gui) ; does not work in mzscheme |
If id has no for-label and normal binding, then help lists all libraries that are known to export a binding for id.
The (help id #:from module-path) variant is similar to (help id), but using only the exports of module-path. (The module-path module is required for-label in a temporary namespace.)
(help frame% #:from scheme/gui) ; equivalent to the above
The (help #:search datum ...) form performs a general search. Searching uses strings; each string datum is used as-is, and any other form of datum is converted to a string using display. No datum is evaluated as an expression.
For example,
(help #:search "web browser" firefox)
searches the documentation index for references that include the phrase “web browser” or “firefox.”