lean4-htt/src/library/tactic/generalize_tactic.cpp
Leonardo de Moura 62788a9ca3 refactor(kernel): fix terminology: "free_var" is actually a loose bound variable
We represent free variables uisng local constants.
We will fix this terminology too.
2018-06-08 13:25:36 -07:00

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/*
Copyright (c) 2016 Microsoft Corporation. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Author: Leonardo de Moura
*/
#include "library/check.h"
#include "library/trace.h"
#include "library/vm/vm_expr.h"
#include "library/vm/vm_name.h"
#include "library/tactic/tactic_state.h"
#include "library/tactic/kabstract.h"
namespace lean {
static vm_obj generalize(transparency_mode m, expr const & e, name const & id, tactic_state s) {
optional<metavar_decl> g = s.get_main_goal_decl();
if (!g) return mk_no_goals_exception(s);
tactic_state_context_cache cache(s);
type_context_old ctx = cache.mk_type_context(m);
expr target = ctx.instantiate_mvars(g->get_type());
expr target_abst = kabstract(ctx, target, e);
if (!has_loose_bvars(target_abst))
return tactic::mk_exception("generalize tactic failed, failed to find expression in the target", s);
expr e_type = ctx.infer(e);
expr new_type = mk_pi(id, e_type, target_abst);
try {
check(ctx, new_type);
} catch (exception & ex) {
return tactic::mk_exception(std::make_exception_ptr(nested_exception("generalize tactic failed, result is not type correct", std::current_exception())), s);
}
expr mvar = ctx.mk_metavar_decl(g->get_context(), new_type);
ctx.assign(head(s.goals()), mk_app(mvar, e));
return tactic::mk_success(set_mctx_goals(s, ctx.mctx(), cons(mvar, tail(s.goals()))));
}
vm_obj tactic_generalize(vm_obj const & e, vm_obj const & n, vm_obj const & m, vm_obj const & s) {
return generalize(to_transparency_mode(m), to_expr(e), to_name(n), tactic::to_state(s));
}
void initialize_generalize_tactic() {
DECLARE_VM_BUILTIN(name({"tactic", "generalize"}), tactic_generalize);
}
void finalize_generalize_tactic() {
}
}