company-xsd

Company-xsd is a backend for company-mode that provides context dependent auto-completions based on the xsd-schemas associated with the xml-file.

Requirements

Company-xsd requires a modern Emacs version (tested with 25.2.2 but anything later than 25.1 should work) and company-mode.

Usage

Like any company-mode backend, the completion purely uses company-mode as frontend with one exception: Force a new guess of schema files. The backend will try to find the schema file to use as soon as the an xml-file is opened. However, if the schema file is specified in the xml-file after it is opened or if it's changed, then it becomes necessary to tell the backend to change schema file. This is done by calling the interactive function company-xsd-init-buffer (if called from code it must be called interactively).

Installation

The most simple and common usage is to add the following to .emacs

(require 'company-xsd)
(add-to-list 'company-backends 'company-xsd-backend)

This will enable the backend as long as the schemas are specified correctly in the root element in the file. If this is not enought there are a few options for manually configuring the backend:

Manual schema specification

In the case that the schema files are not specified correctly, for some reason, then it is possible to set the manually through the variable company-xsd-schemas. The variable is a sequence of (namespace . location) pairs, where:

• namespace is either nil, i.e. uses the global namespace, or a string that is the namespace.
• location is either an URI to the schema or a relative path to the schema.

Note that if company-xsd-schemas is set, then the backend will not guess which schema files to use.

Inserting deducible information

Many xsd-schemas have required attributes and sub-tags that must be present in a tag. The auto-completion tries to insert as much as possible when it can (and when it is implemented). Currently, this is an on-off feature set by variable company-xsd-insert-deducible that defaults to on.

Custom guess schema function

If for some reason, the xml-file specifies a schema in a non-standard way and it's not reasonable to specify the schema file with the company-xsd-schemas variable, then the company-xsd-guess-schemas function can be overriden. The function takes no arguments and should return a sequence of (namespace . location) pairs, the same format as company-xsd-guess-schemas.

Custom uri fetcher

The company backend uses a xsd compiler (xsd.el) that is a part of this package. Because the xsd schemas can contain sub-schemas specified by an URI, the compiler must be able to fetch those sub-schemas. However, if one does not want the editor to redirect these fetches (for example, when working with local schemas that will be published on a different server than the xml files), then one can redefined the function xsd-uri-fetch. This function takes a string argument that is the URI and it is expected to create a new buffer containing the xsd-schema. Furthermore, it is responsible for that the buffer is closed properly (unless it's acceptable with background buffers).