ChainControlParsedFunctionWrapper
This class wraps libMesh::ParsedFunction for use of various parsed ChainControls.
For valid syntax for the function expression, see the function parser site.
The user-defined symbols may include the following:
boolorRealChainControlDataScalar variables
Constant values
Pre-defined symbols that may be used in the function expression are x, y, z, and t, representing the corresponding spatial coordinates and time value.