Albatross.Expression api is created to process and evaluate text based expression strings. The api tokenizes the expression text and create a tree model from the tokens. Using the model, it can evaluate the expression or convert it to a expression of different format. Some applications revert the process by creating the model first and using it to generate certain expression such as a sql query statement. The api also contains a useful ExecutionContext class that allows evaluation of expressions with variables. The variables can be read internally or directly from external objects.