Developer information

Writing documentation

In order for any user-visible change to be accepted into the mainline, it must be accompanied by accurate documentation. The docs are written in an XML dialect similar to XHTML, with a few tags specific to our documentation. For example:

<F1> :help :h help :help subject <F1>

Open the help page. The default page, as specified by helpfile is shown unless subject is specified. If you need help for a specific topic, try :help overview.

creates a new help section for the command :help and for the related key binding, . It also creates help tags for the command, its shortcuts, the key binding, and the general topic, ‘help’. These tags enable linking to this section from other mentions of the topic and from the :help command.

Help tags

The following is a list of the more common XML tags used in help pages, along with their highlight groups.

Layout
p: A paragraph (HelpParagraph)
h1: A first-level heading (HelpHead1)
h2: A second-level heading (HelpHead2)
h3: A third-level heading (HelpHead3)
h4: A fourth-level heading (HelpHead4)
code: A pre-formatted code block. (HelpCode)
note: A note paragraph. (HelpNote)
strut: A horizontal strut which prevents any previous floating elements from appearing below it.
warning: A warning paragraph. (HelpWarning)

Generic
link: A generic link. (HelpLink)
&tab;@topic: The topic of the link. Either a help topic or a fully-qualified URI.
em: Emphasized text. (HelpEm)
str: A string, with its contents wrapped in quotes. (HelpString)
logo: &dactyl.appName;'s logo. (Logo)

Items
item: A help entry (HelpItem)
&tab;tags: See the 'Tagging' section (HelpTags)
&tab;spec: The specification for this item, such as an example command line. (HelpSpec)
&tab;strut: A horizontal formatting strut which ensures that all previous <tags> and <spec> elements appear above the ones that follow.
&tab;type: For options, the type of the option. number, boolean, string, stringlist, or charlist. (HelpType)
&tab;default: For options, the default value. (HelpDefault)
&tab;description: The description of this help item. (HelpDescription)
&tab;&tab;@short: Indicates that this is a short description which should appear between the specs and tags.
a: Required argument. (HelpArg)
oa: Optional argument. (HelpOptionalArg)

Tagging
tags: Space-separated list of strings to tag. Displayed right-aligned, and used for cross-linking. (HelpTags)
@tag: The tag attribute. Applied to any element, generates a <tags> element for the given tags. (HelpTag)

Linking
o: Link to an option. (HelpOpt)
ex: Link to an Ex command. (HelpEx)
k: Link to a key. (HelpKey)
&tab;@name: The name attribute to <k>. When provided, <value> is prepended to the element's contents, i.e., <k name="Tab"/> becomes .
&tab;@mode: The mode attribute to <k>. Some keys have different functions in different modes. You can use this attribute to specify which of the modes (other than Normal) a key pertains to. The <value> is prepended to the element's contents, i.e., <k name="C-i" mode="I"/> becomes , and <k mode="t">i</k> becomes i.
t: Links to an arbitrary help topic. (HelpTopic)

Plugins
@lang: When applied to any element under <plugin>, that element is only visible for a specific locale.
plugin: The container tag used for describing a plugin.
&tab;@name: The name of the plugin. Used as the plugin's help tag.
&tab;@version: The plugin's version number.
&tab;@href: The plugin's home page.
&tab;@summary: A short description of the plugin, shown in its section head.
info: An element with the same attributes as plugin, which may override the latter for specific locales
project: The project for which this plugin was intended.
&tab;@name: The name of the project (i.e., &dactyl.appName;)
&tab;@min-version: The minimum version of the project for which this plugin is intended to work.
&tab;@max-version: The maximum version of the project for which this plugin is intended to work.
author: The plugin's author. May appear more than once.
&tab;@href: The author's home page.
&tab;@email: The author's email address.
license: The plugin's license. May appear more than once.
&tab;@href: The URI of a page which shows or explains the license.

Generating documentation

You can also autogenerate most of the XML help after you have written a new command, mapping or option.

:echo dactyl.generateHelp(commands.get(addons), Extra text

]]>)

Writing plugins

Writing &dactyl.appName; plugins is incredibly simple. Plugins are simply JavaScript files which run with full chrome privileges and have full access to the &dactyl.appName; and &dactyl.host; APIs. Each plugin has its own global object, which means that the variables and functions that you create won't pollute the global window or private dactyl namespaces. This means that there's no need to wrap your plugin in a closure, as is often the practice in JavaScript development. Furthermore, any plugin which is installed in your runtimepath/plugins directory will find its context stored in plugins.<pluginName>, which is often invaluable during development and testing.

Plugins are always initialized after the main window is loaded, so there is no need to write load event handlers. Beyond that, what you may do with your plugins is practically limitless. Plugins have full access to all of the chrome resources that ordinary &dactyl.host; does, along with the entire power of the &dactyl.appName; API. If you need a starting point, have a look at some existing plugins or extensions, especially the &dactyl.appName; source.

Plugin documentation

Plugins should provide inline documentation, which will appear on the :help plugins page. The markup for help entries is the same as the above, along with a few extra plugin-specific entries. Here is an example from the popular flashblock extension:

use strict; XML.ignoreWhitespace = false; XML.prettyPrinting = false; var INFO = <plugin nameflashblock version1.0 hrefhttp://dactyl.sf.net/pentadactyl/plugins#flashblock-plugin summaryFlash Blocker xmlns{NS}> Kris Maglione MIT

This plugin provides the same features as the ever popular FlashBlock Firefox addon. Flash animations are substituted with place holders which play the original animation when clicked. Additionally, this plugin provides options to control which sites can play animations without restrictions, and triggers to toggle the playing of animation on the current page.

'fb' 'flashblock' 'flashblock' 'fb' boolean true

Controls the blocking of flash animations. When true, place holders are substituted for flash animations on untrusted sites.

... </plugin>;

The inline XML is made possible by E4X. It is important that the documentation be assigned to the INFO variable, or &dactyl.appName; will not be able to find it. The XML property changes are not compulsory, but they do prevent certain formatting problems that may occur otherwise. Beginning your file with use strict, while not required, helps to prevent a lot of common errors.

The documentation that you provide behaves exactly as other &dactyl.appName; documentation, which means that the tags you provide are available via :help with full tag completion and cross-referencing support. Although documentation is not required, we strongly recommend that all plugin authors provide at least basic documentation of the functionality of their plugins and of each of the options, commands, and especially mappings that they provide.