Current Status

As of summer 2004, many thorns don't use the above mechanism, instead they directly extend
ADMBase::lapse_evolution_method and/or ADMBase::shift_evolution_method. That is, the thorn implementing a coordinate condition thorn says in its param.ccl:

EXTENDS KEYWORD lapse_evolution_method "Which lapse condition to use"
{
"super-duper" :: "my super-duper new lapse condition"
} ""

(and/or the equivalent for shift_evolution_method).

The thorn then schedules a routine in some suitable schedule bin/group (probably CCTK_PRESTEP or MOL_PRESTEP) to check ADMBase::lapse_evolution_method and/or ADMBase::shift_evolution_method, and if they're equal to the appropriate string, it does the coordinate condition.