lean4-htt/src/library/tactic/clear_tactic.cpp
2016-06-14 21:01:57 -07:00

42 lines
1.6 KiB
C++

/*
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/vm/vm_name.h"
#include "library/tactic/tactic_state.h"
namespace lean {
vm_obj clear(name const & n, tactic_state const & s, bool internal_name) {
optional<metavar_decl> g = s.get_main_goal_decl();
if (!g) return mk_no_goals_exception(s);
metavar_context mctx = s.mctx();
local_context lctx = g->get_context();
optional<local_decl> d = internal_name ? lctx.get_local_decl(n) : lctx.get_local_decl_from_user_name(n);
if (!d)
return mk_tactic_exception(sstream() << "clear tactic failed, unknown '" << n << "' hypothesis", s);
expr l = d->mk_ref();
if (depends_on(g->get_type(), 1, &l))
return mk_tactic_exception(sstream() << "clear tactic failed, result type depends on '" << n << "'", s);
if (optional<local_decl> d2 = lctx.has_dependencies(*d))
return mk_tactic_exception(sstream() << "clear tactic failed, '" << d2->get_pp_name() << "' depends on '"
<< n << "'", s);
lctx.clear(*d);
expr new_g = mctx.mk_metavar_decl(lctx, g->get_type());
mctx.assign(head(s.goals()), new_g);
return mk_tactic_success(set_mctx_goals(s, mctx, cons(new_g, tail(s.goals()))));
}
vm_obj tactic_clear(vm_obj const & n, vm_obj const & s) {
bool internal_name = false;
return clear(to_name(n), to_tactic_state(s), internal_name);
}
void initialize_clear_tactic() {
DECLARE_VM_BUILTIN(name({"tactic", "clear"}), tactic_clear);
}
void finalize_clear_tactic() {
}
}