RosettaCodeData/Task/Runtime-evaluation-In-an-environment/J/runtime-evaluation-in-an-environment-1.j

   EvalWithX=. monad : 0
    'CODE V0 V1'=. y
    (". CODE [ x=. V1) - (". CODE [ x=. V0)
   )

   EvalWithX '^x';0;1
1.71828183