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(************************************************************************)
(* v * The Coq Proof Assistant / The Coq Development Team *)
(* <O___,, * INRIA - CNRS - LIX - LRI - PPS - Copyright 1999-2010 *)
(* \VV/ **************************************************************)
(* // * This file is distributed under the terms of the *)
(* * GNU Lesser General Public License Version 2.1 *)
(************************************************************************)
(* $Id$ *)
open Util
open Names
open Term
open Evd
open Evarutil
open Sign
open Proof_trees
open Refiner
(******************************************)
(* Instantiation of existential variables *)
(******************************************)
let depends_on_evar evk _ (pbty,_,t1,t2) =
try head_evar t1 = evk
with NoHeadEvar ->
try head_evar t2 = evk
with NoHeadEvar -> false
let define_and_solve_constraints evk c evd =
try
let evd = define evk c evd in
let (evd,pbs) = extract_changed_conv_pbs evd (depends_on_evar evk) in
fst (List.fold_left
(fun (evd,b as p) (pbty,env,t1,t2) ->
if b then Evarconv.evar_conv_x env evd pbty t1 t2 else p) (evd,true)
pbs)
with e when Pretype_errors.precatchable_exception e ->
error "Instance does not satisfy constraints."
let w_refine (evk,evi) (ltac_var,rawc) sigma =
if Evd.is_defined sigma evk then
error "Instantiate called on already-defined evar";
let env = Evd.evar_env evi in
let sigma',typed_c =
try Pretyping.Default.understand_ltac true sigma env ltac_var
(Pretyping.OfType (Some evi.evar_concl)) rawc
with _ ->
let loc = Rawterm.loc_of_rawconstr rawc in
user_err_loc
(loc,"",Pp.str ("Instance is not well-typed in the environment of " ^
string_of_existential evk))
in
define_and_solve_constraints evk typed_c (evars_reset_evd sigma' sigma)
(* vernac command Existential *)
let instantiate_pf_com n com pfts =
let gls = top_goal_of_pftreestate pfts in
let sigma = gls.sigma in
let (evk,evi) =
let evl = Evarutil.non_instantiated sigma in
if (n <= 0) then
error "incorrect existential variable index"
else if List.length evl < n then
error "not so many uninstantiated existential variables"
else
List.nth evl (n-1)
in
let env = Evd.evar_env evi in
let rawc = Constrintern.intern_constr sigma env com in
let sigma' = w_refine (evk,evi) (([],[]),rawc) sigma in
change_constraints_pftreestate sigma' pfts
|
