diff options
Diffstat (limited to 'kernel/reduction.ml')
| -rw-r--r-- | kernel/reduction.ml | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/kernel/reduction.ml b/kernel/reduction.ml index 6cd3917c7..8ca596d48 100644 --- a/kernel/reduction.ml +++ b/kernel/reduction.ml @@ -862,6 +862,17 @@ let dest_prod env = in decrec env Context.Rel.empty +let dest_lam env = + let rec decrec env m c = + let t = whd_all env c in + match kind t with + | Lambda (n,a,c0) -> + let d = LocalAssum (n,a) in + decrec (push_rel d env) (Context.Rel.add d m) c0 + | _ -> m,t + in + decrec env Context.Rel.empty + (* The same but preserving lets in the context, not internal ones. *) let dest_prod_assum env = let rec prodec_rec env l ty = @@ -907,3 +918,12 @@ let is_arity env c = let _ = dest_arity env c in true with NotArity -> false + +let eta_expand env t ty = + let ctxt, codom = dest_prod env ty in + let ctxt',t = dest_lam env t in + let d = Context.Rel.nhyps ctxt - Context.Rel.nhyps ctxt' in + let eta_args = List.rev_map mkRel (List.interval 1 d) in + let t = Term.applistc (Vars.lift d t) eta_args in + let t = Term.it_mkLambda_or_LetIn t (List.firstn d ctxt) in + Term.it_mkLambda_or_LetIn t ctxt' |