A context and a result define the input and output parameter interface. Input parameters are defined by the context and the output parameters are defined by the result. Context and result are data carriers.

Context and result are a set of data objects, such as an element, structure or a table. A context or a result of type element can be a text, number, Boolean, quantity, amount and timepoint.

Functions and expressions have a context. A set of attributes defined by the context is used as input values to process a function or an expression. Data objects in a context can consist of 0, 1 or n elements, a structure or a table, each of which is addressed by its name.

The context assigned to a function can be used by all expressions of the expression hierarchy. The input parameters of the expressions are filled either with context or with the result of other expressions.

In the event mode of operation, the context can be changed and can be a part of the result. In this case, the result parameter is not relevant.

The value returned from the function or from an expression after processing is the result. A result consists of one element, a structure or a table.