Being new to XML, I had to decide upon a suitable
editor. You can use any editor capable of editing
ASCII text files, but you'll find that a
editor which is smart makes editing XML
files much more pleasant. At the time of this writing, I still
prefer emacs.
For those that prefer the vi environment (and you know who you are), both vim and gvim provide nice color highlighting as shown below:
Unfortunately, color highlighting is about all vim and gvim offer. Once you get use to working with a powerful editor, you'll only find yourself using these tools in a pinch.
For those that prefer the lack of a slow GUI interface, the emacs editor is well suited for editing XML documents. It is very good at aiding the developer in inserting new elements into the document (or editing existing elements). The following shows that emacs is also capable of color syntax highlighting:
Unfortunately, emacs (at least version
21.2.1) doesn't do this out of the box. You
will need to update your .emacs file. In
addition, to suport XML validation, you will want to create
a $HOME/.catalog file. Please note, this
has only been tested on version 21.2.1 of
emacs. The directions shown here will NOT work with
version 20.7.1 of emacs.
The following shows what you should add to the end of
your .emacs configuration file:
Figure 2.2. Adding XML Support to $HOME/.emacs
;; Enable sgml-mode for our editing of XML documents
(autoload 'sgml-mode "psgml" "Major mode to edit SGML files." t )
(require 'psgml)
;; You can add devloper catalogs (avoiding the need to update
;; /etc/sgml/catalog file), by keeping MASTER catalog file
;; $HOME/.catalog with lines indicating package catalog files to load
;; (in OASIS form). File contents has one or more lines resembling:
;;
;; CATALOG "/home/pkb/usr/share/keyval/catalog/keyval_catalog.oasis"
(setq-default sgml-catalog-files
'("/etc/sgml/catalog"
"~/.catalog"))
;; Create faces for the various components of a XML document
(copy-face 'default 'sgml-start-tag-face)
(set-face-foreground 'sgml-start-tag-face "#4856ad")
(copy-face 'default 'sgml-end-tag-face)
(set-face-foreground 'sgml-end-tag-face "#72398e")
(copy-face 'italic 'sgml-comment-face)
(set-face-foreground 'sgml-entity-face "#298921")
(copy-face 'bold 'sgml-pi-face)
(set-face-foreground 'sgml-comment-face "red")
(copy-face 'bold 'sgml-sgml-face)
(set-face-foreground 'sgml-pi-face "darkgray")
(copy-face 'bold 'sgml-doctype-face)
(set-face-foreground 'sgml-doctype-face "#8e3939")
(copy-face 'default 'sgml-entity-face)
(set-face-foreground 'sgml-entity-face "#77502b")
(copy-face 'bold 'sgml-shortref-face)
(set-face-foreground 'sgml-shortref-face "#d8883c")
;; Map the new faces when psgml mode (xml).
(setq-default sgml-set-face t)
(setq sgml-markup-faces '((start-tag . sgml-start-tag-face)
(end-tag . sgml-end-tag-face)
(comment . sgml-comment-face)
(pi . sgml-pi-face)
(sgml . sgml-sgml-face)
(doctype . sgml-doctype-face)
(entity . sgml-entity-face)
(shortref . sgml-shortref-face)))
The pgsml-mode of
emacs is capable of reading the
DTD associated with your XML source
file (provided it includes a valid DOCTYPE
statement). This is really nice when editing the source
XML. Unfortunately, this hits on one of the sore points
when editing XML documents. It's very difficult to provide
a single location for everyone in the world to get to the
DTD which is used to validate a XML
document. Catalogs are used to provide a public mapping to
local file system to address this issue (its a pain in the
butt - I know).
The following shows how I've configured my
$HOME/.catalog file to load the catalog
file provided by the xml-keyval package:
The following serves as a quick reference to some of emacs more useful commands when working with XML documents:
Table 2.1. emacs XML Keys
| Command | Details |
|---|---|
| -> (C-c-C-e) | This command is used to insert a new
XML element into the document. The cursor must be
outside of any existing element (for example, it
WON'T work if your cursor is located on any of the
characters in
|
| -> (C-c-C-a) | This command is used to edit
the attributes of a XML element into the
document. Your cursor must be within of any existing
element (for example, place it on one of the
characters in a |
| M-q | This command will wrap the current block of XML text you are working on. This saves a lot of time when typing. |
The jEdit - Open Source Text Editor editor is both free and a fairly powerful editor for working with XML documents. It provides a full GUI interface and is able to validate your XML document as you type. You will need to download the necessary plug-ins - but the plug-in extension is built into the editor and pretty close to painless. You can customize its appearance (tweak what views are shown and how they are placed). The following shows an example:
