- STRUCTURE
- SYNOPSIS
- Case splits on a term t that features in the goal as case t of .... 
- DESCRIPTION
- BasicProvers.PURE_CASE_TAC searches the goal for an instance of
case t of ..., and performs a BasicProvers.Cases_on `t`. 
- FAILURE
- BasicProvers.PURE_CASE_TAC fails if there is no instance of
case t of ... in the goal, where the case term is a case constant in
the typebase and all the free variables of t are free in the goal. 
- SEEALSO