NatWeiss/ValTree

ValTree

ValTree is a file format for storing key value pairs in a hierarchy -- more efficient than JSON -- and a C++ class to read / write these files.

There are two problems with JSON:

It can be annoying to have to format data using braces, colons and quotes. (You cannot be lazy.)
The order of data is not guaranteed.

ValTree solves these two issues by making it more simple to type / create files and guarantees the order of values.

Ports to Other Languages

C# port -- thanks to wackoisgod
Java port -- thanks to born2snipe

Example File

ValTree stores files with any file extension, though .txt is encouraged. Here is an example file, Example.txt:

a
	b
		c
		d  1
		e  2.01
		f  something
g-is-long
	h  h is a cool letter
	i
j  1.618
k-is-longer  too

Tabs or spaces can be used to indent the data. Each tab or space puts the current line of data as a child of the previous line, depending on depth.

Data is stored as key value pairs. After the initial tabs or spaces comes the key, then as many tabs or spaces as desired, then the value. The key can be any non-whitespace character. The value is everything remaining on the current line after the key and some whitespace. (Note that values can contain whitespace.)

Values can be strings, integers or floats. When parsing, ValTree reads the value as a string, then also converts it to long and double using strtol and strtod. All three types of data are stored simultaneously as separate data members for quick access.

Each ValTree is a self-contained recursive class containing an array of children. Children are ValTree objects stored at one level deeper than current. Children are returned by reference and guaranteed to be non-null (if a child is not found then an empty static object is returned via ValTree::null()).

Example Code

Here is some example code to load a ValTree, retrieve a value, store a new value, and save:

// load / parse the above example
ValTree v;
v.parse("Example.txt");

// retrieve a value
auto& h = v.getChild("g-is-long").getChild("h");
cout << "The value of 'h' is " << h.getStr() << endl;

// query the tree
auto& key41 = v.query("key1.key2.key3.key4-1");
cout << "The value of 'key1.key2.key3.key4-1' is '" << key41.getStr() << "'" << endl;

// store a new value
v.addChild(ValTree("l", "90,90"));

// save the tree to a new file
v.save("Example-modified.txt");

To Do

Add the ability to get children as a vector.

License

ValTree is licensed under the MIT license.

NatWeiss / ValTree