Patch to add a debugging string to HExtlib.split_nth reverted

[helm.git] / helm / software / components / ng_kernel / nCicReduction.ml

diff --git a/helm/software/components/ng_kernel/nCicReduction.ml b/helm/software/components/ng_kernel/nCicReduction.ml
index 8012f0b753990745d037e3ee0a4d678f1f6c4398..1815ceedfcf5c87e9d387068ffbfb039c76763ff 100644 (file)
--- a/helm/software/components/ng_kernel/nCicReduction.ml
+++ b/helm/software/components/ng_kernel/nCicReduction.ml
@@ -15,6 +15,8 @@ module C = NCic
 module Ref = NReference
 module E = NCicEnvironment
 
+exception AssertFailure of string Lazy.t;;
+
 module type Strategy = sig
   type stack_term
   type env_term
@@ -363,24 +365,32 @@ let are_convertible ~metasenv ~subst =
   aux false 
 ;;
 
-let rec head_beta_reduce ?(delta=max_int) ?(upto=(-1)) t l =
+let rec head_beta_reduce ~delta ~upto ~subst t l =
  match upto, t, l with
   | 0, C.Appl l1, _ -> C.Appl (l1 @ l)
   | 0, t, [] -> t
   | 0, t, _ -> C.Appl (t::l)
-  | _, C.Appl (hd::tl), _ -> head_beta_reduce ~delta ~upto hd (tl @ l)
+  | _, C.Meta (n,ctx), _ ->
+     (try
+       let _,_, term,_ = NCicUtils.lookup_subst n subst in
+       head_beta_reduce ~delta ~upto ~subst 
+         (NCicSubstitution.subst_meta ctx term) l
+     with NCicUtils.Subst_not_found _ -> if l = [] then t else C.Appl (t::l))
+  | _, C.Appl (hd::tl), _ -> head_beta_reduce ~delta ~upto ~subst hd (tl @ l)
   | _, C.Lambda(_,_,bo), arg::tl ->
      let bo = NCicSubstitution.subst arg bo in
-     head_beta_reduce ~delta ~upto:(upto - 1) bo tl
+     head_beta_reduce ~delta ~upto:(upto - 1) ~subst bo tl
   | _, C.Const (Ref.Ref (_, Ref.Def height) as re), _ 
     when delta <= height ->
       let _, _, bo, _, _, _ = NCicEnvironment.get_checked_def re in
-      head_beta_reduce ~upto ~delta bo l
+      head_beta_reduce ~upto ~delta ~subst bo l
   | _, t, [] -> t
   | _, t, _ -> C.Appl (t::l)
 ;;
 
-let head_beta_reduce ?delta ?upto t = head_beta_reduce ?delta ?upto t [];;
+let head_beta_reduce ?(delta=max_int) ?(upto= -1) ?(subst=[]) t = 
+  head_beta_reduce ~delta ~upto ~subst t []
+;;
 
 type stack_item = RS.stack_term
 type environment_item = RS.env_term
@@ -391,4 +401,19 @@ let reduce_machine = R.reduce
 let from_stack = RS.from_stack
 let unwind = R.unwind
 
+let _ = 
+  NCicUtils.set_head_beta_reduce (fun ~upto t -> head_beta_reduce ~upto t);
+  NCicPp.set_head_beta_reduce (fun ~upto t -> head_beta_reduce ~upto t);
+;;
+
+(* if n < 0, then splits all prods from an arity, returning a sort *)
+let rec split_prods ~subst context n te =
+  match (n, R.whd ~subst context te) with
+   | (0, _) -> context,te
+   | (n, C.Sort _) when n <= 0 -> context,te
+   | (n, C.Prod (name,so,ta)) ->
+       split_prods ~subst ((name,(C.Decl so))::context) (n - 1) ta
+   | (_, _) -> raise (AssertFailure (lazy "split_prods"))
+;;
+
 (* vim:set foldmethod=marker: *)