tactic clear_tactic(name const & n) {
auto fn = [=](environment const &, io_state const &, proof_state const & _s) -> optional<proof_state> {
if (!_s.get_goals()) {
throw_no_goal_if_enabled(_s);
return none_proof_state();
}
proof_state s = apply_substitution(_s);
goals const & gs = s.get_goals();
goal g = head(gs);
goals tail_gs = tail(gs);
if (auto p = g.find_hyp(n)) {
expr const & h = p->first;
unsigned i = p->second;
buffer<expr> hyps;
g.get_hyps(hyps);
hyps.erase(hyps.size() - i - 1);
if (depends_on(g.get_type(), h)) {
throw_tactic_exception_if_enabled(s, sstream() << "invalid 'clear' tactic, conclusion depends on '"
<< n << "'");
return none_proof_state();
}
if (auto h2 = depends_on(i, hyps.end() - i, h)) {
throw_tactic_exception_if_enabled(s, sstream() << "invalid 'clear' tactic, hypothesis '" << *h2
<< "' depends on '" << n << "'");
return none_proof_state();
}
name_generator ngen = s.get_ngen();
expr new_type = g.get_type();
expr new_meta = mk_app(mk_metavar(ngen.next(), Pi(hyps, new_type)), hyps);
goal new_g(new_meta, new_type);
substitution new_subst = s.get_subst();
assign(new_subst, g, new_meta);
proof_state new_s(s, goals(new_g, tail_gs), new_subst, ngen);
return some_proof_state(new_s);
} else {
throw_tactic_exception_if_enabled(s, sstream() << "invalid 'clear' tactic, goal does not have a hypothesis "
<< " named '" << n << "'");
return none_proof_state();
}
};
return tactic01(fn);
}
tactic revert_tactic(name const & n) {
auto fn = [=](environment const &, io_state const &, proof_state const & s) -> optional<proof_state> {
goals const & gs = s.get_goals();
if (empty(gs)) {
throw_no_goal_if_enabled(s);
return none_proof_state();
}
goal g = head(gs);
goals tail_gs = tail(gs);
if (auto p = g.find_hyp(n)) {
expr const & h = p->first;
unsigned i = p->second;
buffer<expr> hyps;
g.get_hyps(hyps);
hyps.erase(hyps.size() - i - 1);
if (optional<expr> other_h = depends_on(i, hyps.end() - i, h)) {
throw_tactic_exception_if_enabled(s, sstream() << "invalid 'revert' tactic, hypothesis '" << local_pp_name(*other_h)
<< "' depends on '" << local_pp_name(h) << "'");
return none_proof_state(); // other hypotheses depend on h
}
name_generator ngen = s.get_ngen();
expr new_type = Pi(h, g.get_type());
expr new_meta = mk_app(mk_metavar(ngen.next(), Pi(hyps, new_type)), hyps);
goal new_g(new_meta, new_type);
substitution new_subst = s.get_subst();
assign(new_subst, g, mk_app(new_meta, h));
proof_state new_s(s, goals(new_g, tail_gs), new_subst, ngen);
return some_proof_state(new_s);
} else {
throw_tactic_exception_if_enabled(s, sstream() << "invalid 'revert' tactic, unknown hypothesis '" << n << "'");
return none_proof_state();
}
};
return tactic01(fn);
}
tactic change_goal_tactic(elaborate_fn const & elab, expr const & e) {
return tactic([=](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 proof_state_seq();
}
expr t = head(gs).get_type();
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);
substitution subst = new_s.get_subst();
auto tc = mk_type_checker(env);
constraint_seq cs;
if (tc->is_def_eq(t, *new_e, justification(), cs)) {
if (cs) {
unifier_config cfg(ios.get_options());
buffer<constraint> cs_buf;
cs.linearize(cs_buf);
to_buffer(new_s.get_postponed(), cs_buf);
unify_result_seq rseq = unify(env, cs_buf.size(), cs_buf.data(), subst, cfg);
return map2<proof_state>(rseq, [=](pair<substitution, constraints> const & p) -> proof_state {
substitution const & subst = p.first;
constraints const & postponed = p.second;
substitution new_subst = subst;
expr final_e = new_subst.instantiate_all(*new_e);
expr M = g.mk_meta(mk_fresh_name(), final_e);
goal new_g(M, final_e);
assign(new_subst, g, M);
return proof_state(new_s, cons(new_g, tail(gs)), new_subst, postponed);
});
}
expr M = g.mk_meta(mk_fresh_name(), *new_e);
goal new_g(M, *new_e);
assign(subst, g, M);
return proof_state_seq(proof_state(new_s, cons(new_g, tail(gs)), subst));
} else {
throw_tactic_exception_if_enabled(new_s, [=](formatter const & fmt) {
format r = format("invalid 'change' tactic, the given type");
r += pp_indent_expr(fmt, *new_e);
r += compose(line(), format("does not match the goal type"));
r += pp_indent_expr(fmt, t);
return r;
});
return proof_state_seq();
}
}
return proof_state_seq();
});
}
static proof_state_seq apply_tactic_core(environment const & env, io_state const & ios, proof_state const & s,
expr const & _e, buffer<constraint> & cs,
add_meta_kind add_meta, subgoals_action_kind subgoals_action,
optional<unifier_kind> const & uk = optional<unifier_kind>()) {
goals const & gs = s.get_goals();
if (empty(gs)) {
throw_no_goal_if_enabled(s);
return proof_state_seq();
}
bool class_inst = get_apply_class_instance(ios.get_options());
name_generator ngen = s.get_ngen();
std::shared_ptr<type_checker> tc(mk_type_checker(env, ngen.mk_child()));
goal g = head(gs);
goals tail_gs = tail(gs);
expr t = g.get_type();
expr e = _e;
auto e_t_cs = tc->infer(e);
e_t_cs.second.linearize(cs);
expr e_t = e_t_cs.first;
buffer<expr> metas;
local_context ctx;
bool initialized_ctx = false;
unifier_config cfg(ios.get_options());
if (uk)
cfg.m_kind = *uk;
if (add_meta != DoNotAdd) {
unsigned num_e_t = get_expect_num_args(*tc, e_t);
if (add_meta == AddDiff) {
unsigned num_t = get_expect_num_args(*tc, t);
if (num_t <= num_e_t)
num_e_t -= num_t;
else
num_e_t = 0;
} else {
lean_assert(add_meta == AddAll);
}
for (unsigned i = 0; i < num_e_t; i++) {
auto e_t_cs = tc->whnf(e_t);
e_t_cs.second.linearize(cs);
e_t = e_t_cs.first;
expr meta;
if (class_inst && binding_info(e_t).is_inst_implicit()) {
if (!initialized_ctx) {
ctx = g.to_local_context();
initialized_ctx = true;
}
bool use_local_insts = true;
bool is_strict = false;
auto mc = mk_class_instance_elaborator(
env, ios, ctx, ngen.next(), optional<name>(),
use_local_insts, is_strict,
some_expr(head_beta_reduce(binding_domain(e_t))), e.get_tag(), cfg, nullptr);
meta = mc.first;
cs.push_back(mc.second);
} else {
meta = g.mk_meta(ngen.next(), head_beta_reduce(binding_domain(e_t)));
}
e = mk_app(e, meta);
e_t = instantiate(binding_body(e_t), meta);
metas.push_back(meta);
}
}
metavar_closure cls(t);
cls.mk_constraints(s.get_subst(), justification());
pair<bool, constraint_seq> dcs = tc->is_def_eq(t, e_t);
if (!dcs.first) {
throw_tactic_exception_if_enabled(s, [=](formatter const & fmt) {
format r = format("invalid 'apply' tactic, failed to unify");
r += pp_indent_expr(fmt, t);
r += compose(line(), format("with"));
r += pp_indent_expr(fmt, e_t);
return r;
});
return proof_state_seq();
}
dcs.second.linearize(cs);
unify_result_seq rseq = unify(env, cs.size(), cs.data(), ngen.mk_child(), s.get_subst(), cfg);
list<expr> meta_lst = to_list(metas.begin(), metas.end());
return map2<proof_state>(rseq, [=](pair<substitution, constraints> const & p) -> proof_state {
substitution const & subst = p.first;
constraints const & postponed = p.second;
name_generator new_ngen(ngen);
substitution new_subst = subst;
expr new_e = new_subst.instantiate_all(e);
assign(new_subst, g, new_e);
goals new_gs = tail_gs;
if (subgoals_action != IgnoreSubgoals) {
buffer<expr> metas;
for (auto m : meta_lst) {
if (!new_subst.is_assigned(get_app_fn(m)))
metas.push_back(m);
}
if (subgoals_action == AddRevSubgoals) {
for (unsigned i = 0; i < metas.size(); i++)
new_gs = cons(goal(metas[i], new_subst.instantiate_all(tc->infer(metas[i]).first)), new_gs);
} else {
lean_assert(subgoals_action == AddSubgoals || subgoals_action == AddAllSubgoals);
if (subgoals_action == AddSubgoals)
remove_redundant_metas(metas);
unsigned i = metas.size();
while (i > 0) {
--i;
new_gs = cons(goal(metas[i], new_subst.instantiate_all(tc->infer(metas[i]).first)), new_gs);
}
}
}
return proof_state(s, new_gs, new_subst, new_ngen, postponed);
});
}