Help:Command

From Wiki
Jump to navigation Jump to search

TODO: This page documents the situation that will become active in a few days/a week when a newly developed wiki extension will be ported over from the test wiki. This page is written in preparation. Soon, this todo block will be deleted.

We have a heatwave right now, and even though there are some things in the extension that I still want to improve on, it is too hot in the actual office to do any programming. Instead, I am on the couch in front of a fan.

--Taco (talk) 22:52, 9 August 2020 (CEST) (See: To-Do List)


Common problems

Normally, a page like this would start with a simple introduction and hide the issues at the bottom. But if you are not familiar with editing XML and/or how the Command setup works, you are very likely to see errors before you have read the rest of this page. So here we go:

  • I tried to create a new page but the form loads up empty.
You tried to create a page for a ConTeXt command that is not documented in the interface files. Check that you didn't make a typing error first. Alternatively, it is possible that the ConTeXt command is a generated instance, and in that case the page should be a #REDIRECT. If neither are the case or you are unsure, ask for advice on the mailing list.
  • When saving my edit, I see some red text with an XML error.
Command pages must be either well-formed XML, or nothing but a #REDIRECT. You likely made a booboo with an XML tag or have an unquoted < or > or & somewhere. Only the content of <pre>\, `<xmlcode>`, `<texcode>`, and `<context>` are exempt from the normal XML rules (but on the downside, they cannot be nested)
  • I tried to edit a section, but I see an error that says 'Section not found'.
Only the predefined top-level sections can be edited separately (this limitation is likely to stay).
  • I get a warning that the revision is outdated at the top of the edit screen
This happens when the command definition has been updated externally, for example after a new ConTeXt distribution has been installed on the server. The warning should be harmless (this warning is likely to be removed in the future)

Introduction

The pages under Command are managed by a plugin that saves the page body either as an XML interface documentation record or as a redirect. So, a page under control of the plugin:

  • should be XML with the `<cd:commandgroup>` top-level tag.
  • or a single line with a `#REDIRECT` to another page

The documentation inside the XML tree can make use of (some) wiki markup, as explained below.

Editing a Command page will normally result in an automatically filled edit screen. The extension has a database of all the command definitions from the ConTeXt distribution, and it will preload the wanted database record in the Edit field when a previously non-existing page is requested.

As explained in Command, some commands are instances of definitions, and pages for such commands are supposed to be redirects to the matching generator record. Guessing the matching generator record is not always easy, but the wiki search should help. All the generator records should already have their pages created, and since they all list all instances they define, it should be possible to find the 'parent' from looking at the search results.

Editing XML documentation

First off: Don't Panic! You do not have to use XML throughout! All user-supplied documentation can use wiki code just like on the rest of the wiki pages, you just have to be a little careful about where to put it. You never have to alter the pre-generated XML.

However, the goal of this documentation is to be easily exportable to other documentation efforts, so some care should be taken in deciding what the best way to add text. Here are some guidelines that may eventually even become enforced by the extension:

  • Please do not add options to or delete portions of the pre-generated XML!
  • Do not use block-level objects like subsections, lists, tables and figures except in the Description and Examples sections. Most documentation fields are intended to be used as running text.
  • With the exception of {{cmd}}, {{gen}} and {{todo}}, do not use wiki templates. Wiki templates can change over time, and that creates a nasty external dependency, so they are disallowed.
  • Don't use regular HTML tags except for <pre> (but <texcode> is usually a better choice) and <code>. For bold or italic text, use the regular wikicode markup. Most inline wikicode can be used anywhere, and the sectioning codes can be used in descriptions, examples, and notes. The one exception is `<nowiki>`, that is forbidden everywhere.
  • External links can be better placed in the See also section than in your main documentation.
  • See below for a 'structural' way to refer to command parameters and options.

Editing the 'Summary'

Simply finish or alter the sentence within the <cd:shortdesc> tag. The Summary should be a single sentence that gives a terse description of what the command does.

Editing the 'Instances'

Some commands have a separate section with the list of predefined instances of the command. You can add some documentation into the <cd:constant> tags of this instance list, if you believe that will be useful.

Editing the 'Settings'

The Settings output is the Syntax table of the command or command variant, followed by a table listing the documented options. In a command with variants, there could be multiple Settings sections, with the variant name as the suffix to the title(s).


Not all options to every command actually need documentation, which is why the output only shows documented options. This helps keep the wiki page size within limits and helps the user maintain general overview.

Adding documentation for a command is done by typing wiki text into one of the following XML tags:

<cd:assignmentsdoc> For documentation that applies to all key-values of a parameter option
<cd:paramdoc> For documentation that applies to all values of a specific key-value parameter
<cd:keywordsdoc> For documentation that applies to all values of a keyword option
<cd:constant> For documentation that applies to a specific key-value parameter value or a specific keyword

For documentation that applies to arguments that are neither parameter nor keyword lists, you can put the documentation in the XML tag for the actual argument, for example in the <cd:content> of arguments 1 and 2 of \doifelse.

Editing the 'Description'

Arguably the most important section for a command reference. If you want to put a heading in remember to start at level three (===) and don't forget that such sections cannot be edited separately within a Command page. If it becomes unwieldy, consider editing the text in a separate scratch area like the Special:MyTalk page, then pasting the complete edited text back in.

Editing the 'Examples'

Each <cd:example> tag will create a level 3 heading. If you want to give it a specific title, fill in the title attribute. If you don't, examples will be numbered automatically as Example 1, Example 2, et cetera.

As for Description, don't forget that examples cannot be edited separately within a Command page. If it becomes unwieldy, consider editing the example in a separate scratch area like the Special:MyTalk page, then pasting the complete edited example back in.

Editing the 'Notes'

Use a <cd:note> to report something that is not quite part of the regular command reference. For example, if you find a bug in this command in a specific ConTeXt version. You can fill in the author and date attributes manually, or use the shortcuts for signing a page:

<cd:note author="~~~" date="~~~~~">...</cd:note>

That is three tildes for the author name + link, and five tildes for the timestamp).

Please do not edit other people's notes, create a new one if needed.

Editing the 'See also'

This section is meant for cross-references that do not need to be in the actual Description or Settings documentation. Normally, a few values are pre-filled because the cross-reference was detected while creating the database record for this command. But it is not always easy to deduct cross-references from the original interface XML, so chances are that there are many more interesting links that the database generator has missed. Feel free to add any relevant links. If you want to add an explanatory text as well, you can key that in as the XML tag content.

In case the comment containing the list of possible entries has been deleted from the record, here are the acceptable types:

<!-- one or more of these:
<cd:commandref name="xx"></cd:commandref>
<cd:wikipage   page="xx"></cd:wikipage>
<cd:url        url="https://xx"></cd:url>
<cd:manual     pdf="xx"></cd:manual>
<cd:source     file="xx"></cd:source>
-->

Fill in the xx with a suitable entry. Here are examples of the expected attribute values:

<cd:commandref name="contextversion"></cd:commandref>
<cd:wikipage   page="Main Page"></cd:wikipage>
<cd:url        url="https://www.pragma-ade.com"></cd:url>
<cd:manual     pdf="xml-mkiv.pdf"></cd:manual>
<cd:source     file="cont-ini.mkiv"></cd:source>

Referencing

Referring to outside of the current page

You can use the normal wiki links, but it is generally better to add such links to the 'See also section instead.

Referring to another section

Simply use the normal Wiki syntax for internal links, e.g. #Introduction.

Referring to an argument, option or value

While writing documentation, it is often necessary to refer to a specific option or parameter. For this purpose, there is one extra XML element that can be used within the Command documentation.

The XML tag <cd:iref/> defines an empty element that can be used to reference specific arguments, parameters, or even parameter values from anywhere within the documentation. It accepts up to four attributes:

variant the name of a variant, as given in the variant attribute of the <cd:command> tag. If the XML attribute is missing from <cd:command> but there are multiple variants, then use variant="".
ordinal the ordinal number of a command argument, as in the ordinal attribute of the relevant argument tag
name the name of a parameter in a key-value command (the value of a name attribute of a <cd:parameter>)
type the value of a parameter in a key-value command, or a keyword. (the value of a type attribute on a <cd:constant> )
  • When inside of a command argument's substructure, if you are referring to something within the same argument, then ordinal is optional.
  • Similarly, when inside of a variant command and referring to something within the same variant, then the variant is optional.
  • Outside of the Settings section, both ordinal and variant attributes are required, even if there is only one variant (variant="") or one argument (ordinal="1"). This is because there could be a future extension to the command that would add either an argument or a variant.

Further, depending on what you want to show, name and type can both specified, or one of them, or both. The formatter will try to show something useful in either case.

A warning: During preview, <cd:iref/> will not be able to access data from outside of the current section you are editing. This will (barring errors) resolve itself once the section is saved and the full page is reloaded.