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Attributes

Attributes are a way of storing untyped key/value pairs on elements. These generally have two uses: styling and meta data tracking.

An attribute can be set in a few different ways on elements.

As a member declaration​

In a top level declaration, you can declare an attribute with the attribute member syntax. attr: followed by the key name of the attribute optionally followed by a value expression. The value expression can be any expression that returns a string, boolean value, or enum value.

template Thing {

    attr:valid;
    
    attr:abc = "xyz";
    
    attr:someKeyCode = KeyCode.A;
    
    attr:somethingBoolean = true;
    
    attr:someExpression = ComputeSomething();
    
}

As an invocation member​

When applying an attribute to an element invocation, the same rules/apis apply as in the top level declaration member version.

template Example render {

    SomeElement(attr:valid);
    
    SomeElement(attr:abc = "xyz");
    
    SomeElement(attr:someKeyCode = KeyCode.A);
    
    SomeElement(attr:somethingBoolean = true);
    
    SomeElement(attr:someExpression = ComputeSomething());

Using an ElementReference​

When using an ElementReference to set attributes you instead use the C# api. There is also an api for reading attributes with string GetAttribute(string key) and bool HasAttribute(string key).


elementReference.SetAttribute("key", value);