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PropertyList XML files: Difference between revisions
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David Megginson: http://www.mail-archive.com/flightgear-devel@flightgear.org/msg03740.html
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m (David Megginson: http://www.mail-archive.com/flightgear-devel@flightgear.org/msg03740.html) |
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Not everything that is read from an XML file resides in the main property tree; some subsystems also use XML files for initial configuration information. There are different kinds of data. The property tree is meant to represent the shared state of the program; when a subsystem happens to use an XML file to set up its internal state -- information that is of no use to the rest of the program and that cannot be changed without a reinit. Temporary trees are usually deleted as soon as the subsystem is set up (i.e. they exist for perhaps 0.1 sec). We could just as easily use another format for internal initialization, but since the XML support is already available, it was the easiest route. | Not everything that is read from an XML file resides in the main property tree; some subsystems also use XML files for initial configuration information. There are different kinds of data. The property tree is meant to represent the shared state of the program; when a subsystem happens to use an XML file to set up its internal state -- information that is of no use to the rest of the program and that cannot be changed without a reinit. Temporary trees are usually deleted as soon as the subsystem is set up (i.e. they exist for perhaps 0.1 sec). We could just as easily use another format for internal initialization, but since the XML support is already available, it was the easiest route. | ||
FlightGear is getting more sophisticated -- there's more to learn if you want to customize things, but that's only because there's so much more that | |||
you can customize. | |||
The config files serve many different purposes; using the XML-based property-list format for all of them helps a lot, since it allows some common structure and reusable code among all the formats. Imagine if we had one file format for preferences, a different one for panels (say, with fixed-length fields), a different one for saving a flight (perhaps a binary format), another one for sound configuration (perhaps an INI file), a different one for top-level aircraft configuration (perhaps CSV), yet another one for configuring 3D models (perhaps embedded data strings in the 3D files themselves), etc. etc. | |||
To work with PropertyList-XML files, you can use various means, such as: | To work with PropertyList-XML files, you can use various means, such as: | ||