Jon Berndt wrote:
Can anyone tell me if/where the props.html file is that describes the property system? 
can't seem to find it in the source tree or on the web sites - but it IS in simgear 

There doesn't seem to be a file called props.html, and as far as I can remember there hasn't been any.

The property system is best described as an in-memory LDAP database which holds the state of global variables. The system has a tree like hierarchy (like a file system) and has a root node, sub nodes (like subdirectories) and end-nodes (variables).

All variables are kept internally as raw values and can be converted to any other supported type (boolean, int, float double and string).

Like a file system, every node can be accessed relative to the current node, or absolute to the root node.

The property system also allows aliasing nodes to other nodes (like symbolic linking files or directories to other files or directories) and may be assigned read-only or read-write.

If necessary it would be possible for parts of the program to hold it's own property tree, which is inaccessible from the global property tree, by keeping track of it's own root-node.

Property I/O code allows one to easily read the tree from, or write the tree to an XML file.



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