FDBG provides a service to assign names to Prolog terms for later reference. A name is an atom and it is usually associated with a compound term containing constraint variables, or with a single variable. In the former case, each variable appearing in the compound term is also assigned a name automatically by FDBG. This auto-assigned name is derived from the name of the term; see FDBG Name Auto-Generation.
Perhaps the most useful utilization of names is
annotation, another service of FDBG. Here, each variable
appearing in a Prolog term is replaced with a compound term describing
it (i.e. containing its name, the variable itself, and some data
regarding its domain). During annotation, unnamed constraint variables
are also given a unique "anonymous" name automatically, these names
begin with a fdvar prefix. See FDBG Writing Visualizers.
The names will be used by the built-in visualizers when referring to constraint variables, and they can also be used to retrieve the terms assigned to them in user defined visualizers. See FDBG Visualizers.