Geoff Burn defines eVALuators E0, E1, E2 and E3 which when applied to an expression, reduce it to varying degrees. E0 does no eVALuation, E1 it eVALuates to {weak head normal form} (WHNF), E2 eVALuates the structure of a list, i.e. it eVALuates it either to NIL or eVALuates it to a CONS and then applies E2 to the second argument of the CONS. E3 eVALuates the structure of a list and eVALuates each element of the list to WHNF. This concept can be extended to data structures other than lists and forms the basis of the {eVALuation transformer} style of {strictness analysis}. (1994-12-12)