action_result by_contradiction_action() {
state & s = curr_state();
expr target = whnf(s.get_target());
if (!is_prop(target)) return action_result::failed();
if (blast::is_false(target)) return action_result::failed();
expr not_target;
if (is_not(target, not_target)) {
s.set_target(mk_arrow(not_target, mk_constant(get_false_name())));
return intros_action(1);
}
blast_tmp_type_context tmp_tctx;
optional<expr> target_decidable = tmp_tctx->mk_class_instance(mk_app(mk_constant(get_decidable_name()), target));
if (!target_decidable) return action_result::failed();
expr href = s.mk_hypothesis(get_app_builder().mk_not(target));
auto pcell = new by_contradiction_proof_step_cell(href);
s.push_proof_step(pcell);
s.set_target(mk_constant(get_false_name()));
trace_action("by_contradiction");
return action_result::new_branch();
}
bool is_connective(name const & n) const {
return
n == get_or_name() ||
n == get_and_name() ||
n == get_not_name() ||
n == get_iff_name() ||
n == get_not_name() ||
n == get_ite_name() ||
n == get_true_name() ||
n == get_false_name();
}
void initialize_resolve_macro() {
g_resolve_macro_name = new name("resolve");
g_resolve_opcode = new std::string("Res");
g_or = new expr(Const(get_or_name()));
g_not = new expr(Const(get_not_name()));
g_false = new expr(Const(get_false_name()));
g_or_elim = new expr(Const(get_or_elim_name()));
g_or_intro_left = new expr(Const(get_or_intro_left_name()));
g_or_intro_right = new expr(Const(get_or_intro_right_name()));
g_absurd_elim = new expr(Const(get_absurd_name()));
g_var_0 = new expr(mk_var(0));
g_resolve_macro_definition = new macro_definition(new resolve_macro_definition_cell());
register_macro_deserializer(*g_resolve_opcode,
[](deserializer &, unsigned num, expr const * args) {
if (num != 3)
throw corrupted_stream_exception();
return mk_resolve_macro(args[0], args[1], args[2]);
});
}
