Motivation

Cactus functions may need to pass information through a generic interface. In the past, we have used various ad hoc means to do this, and we often had trouble passing "extra" information that wasn't anticipated in the original design. For example, for periodic output of grid variables, CCTK_OutputVarAsByMethod() requires that any parameters (such as hyperslabbing parameters) be appended as an option string to the variable's character string name. Similarly, elliptic solvers often need to pass various parameters, but we haven't had a good way to do this.

Key/value tables (tables for short) provide a clean solution to these problems. They're implemented by the Util_Table* functions (described in detail in the Reference Manual).