lean2/src/library/tactic/assert_tactic.cpp
2015-03-12 14:52:41 -07:00

67 lines
3.1 KiB
C++

/*
Copyright (c) 2014 Microsoft Corporation. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Author: Leonardo de Moura
*/
#include "kernel/abstract.h"
#include "library/constants.h"
#include "library/tactic/tactic.h"
#include "library/tactic/elaborate.h"
#include "library/tactic/expr_to_tactic.h"
namespace lean {
expr mk_assert_tactic_expr(name const & id, expr const & e) {
return mk_app(mk_constant(get_tactic_assert_hypothesis_name()),
mk_constant(id), e);
}
tactic assert_tactic(elaborate_fn const & elab, name const & id, expr const & e) {
return tactic01([=](environment const & env, io_state const & ios, proof_state const & s) {
proof_state new_s = s;
goals const & gs = new_s.get_goals();
if (!gs) {
throw_no_goal_if_enabled(s);
return none_proof_state();
}
bool report_unassigned = true;
if (auto new_e = elaborate_with_respect_to(env, ios, elab, new_s, e, none_expr(), report_unassigned)) {
goals const & gs = new_s.get_goals();
goal const & g = head(gs);
if (g.find_hyp(id)) {
throw_tactic_exception_if_enabled(s, sstream() << "invalid 'assert' tactic, goal already has a "
"hypothesis named '" << id << "'");
// goal already has a hypothesis named id
return none_proof_state();
}
name_generator ngen = new_s.get_ngen();
expr new_meta1 = g.mk_meta(ngen.next(), *new_e);
goal new_goal1(new_meta1, *new_e);
expr new_local = mk_local(ngen.next(), id, *new_e, binder_info());
buffer<expr> hyps;
g.get_hyps(hyps);
hyps.push_back(new_local);
expr new_mvar2 = mk_metavar(ngen.next(), Pi(hyps, g.get_type()));
hyps.pop_back();
expr new_meta2_core = mk_app(new_mvar2, hyps);
expr new_meta2 = mk_app(new_meta2_core, new_local);
goal new_goal2(new_meta2, g.get_type());
substitution new_subst = new_s.get_subst();
assign(new_subst, g, mk_app(new_meta2_core, new_meta1));
return some_proof_state(proof_state(new_s, cons(new_goal1, cons(new_goal2, tail(gs))), new_subst, ngen));
}
return none_proof_state();
});
}
void initialize_assert_tactic() {
register_tac(get_tactic_assert_hypothesis_name(),
[](type_checker &, elaborate_fn const & fn, expr const & e, pos_info_provider const *) {
name id = tactic_expr_to_id(app_arg(app_fn(e)), "invalid 'assert' tactic, argument must be an identifier");
check_tactic_expr(app_arg(e), "invalid 'assert' tactic, argument must be an expression");
return assert_tactic(fn, id, get_tactic_expr_expr(app_arg(e)));
});
}
void finalize_assert_tactic() {
}
}