# Assignment 6 (week 7)

## Evaluation order in Combinatory Logic

1. Give a term that the lazy evaluators (either the Haskell evaluator,
or the lazy version of the OCaml evaluator) do not evaluate all the
way to a normal form, i.e., that contains a redex somewhere inside of
it after it has been reduced.

<!-- reduce3 (FA (K, FA (I, I))) -->


2. One of the 
[[criteria we established for classifying reduction strategies|
topics/week3_evaluation_order]]
strategies is whether they reduce subexpressions hidden under lambdas.
That is, for a term like `(\x y. x z) (\x. x)`, do we reduce to
`\y.(\x.x) z` and stop, or do we reduce further to `\y.z`?  Explain
what the corresponding question would be for CL. Using either the
OCaml CL evaluator or the Haskell evaluator developed in the wiki
notes, prove that the evaluator does reduce expressions inside of
"functional" CL expressions.  Then provide a modified evaluator that
does not perform reductions in those positions.

<!-- just add early no-op cases for Ka and Sab -->