A function is an object that produces a quantity from a number of fields. The original purpose for introducing functions was to provide an easy way to describe concentration dependent diffusivities, but their usefulness goes beyond this single purpose. As a result, in the present implementation, functions are not widely supported by the available operators, but this will change in the future.
function functionName [ -parameters parameterList ]
The available functions and their parameters are listed in section 3.1.
The function command creates a new command and returns the name of this command. Currently, this is only used for instantiation of the object-oriented data structure describing the function in the model.
Parameter lists are simply ordered lists of strings describing one of a Field, a Function, or a TCL variable name. The string for a Function is the value returned by a previous function command.