private Map<String, ShaderNodeDefinition> getNodeDefinitions() {
        if (nodeDefinitions == null) {
            nodeDefinitions = new HashMap<>();
        }
        return nodeDefinitions;
    }
check the types of a mapping, left type must match right type take the
swizzle into account

@param mapping the mapping
@param statement1 the statement being read
@throws MatParseException in case of a syntax error
jme3-core/src/plugins/java/com/jme3/material/plugins/ShaderNodeLoaderDelegate.java