expr visit_projection(name const & fn, buffer<expr> const & args) {
projection_info const & info = *get_projection_info(env(), fn);
expr major = visit(args[info.m_nparams]);
buffer<bool> rel_fields;
name I_name = *inductive::is_intro_rule(env(), info.m_constructor);
get_constructor_info(info.m_constructor, rel_fields);
lean_assert(info.m_i < rel_fields.size());
lean_assert(rel_fields[info.m_i]); /* We already erased irrelevant information */
/* Adjust projection index by ignoring irrelevant fields */
unsigned j = 0;
for (unsigned i = 0; i < info.m_i; i++) {
if (rel_fields[i])
j++;
}
expr r;
if (has_trivial_structure(I_name, rel_fields)) {
lean_assert(j == 0);
r = major;
} else {
r = mk_app(mk_proj(j), major);
}
/* Add additional arguments */
for (unsigned i = info.m_nparams + 1; i < args.size(); i++)
r = mk_app(r, visit(args[i]));
return r;
}
expr apply(expr const & a) {
bool sh = false;
if (is_shared(a)) {
auto r = m_cache.find(a.raw());
if (r != m_cache.end())
return r->second;
sh = true;
}
switch (a.kind()) {
case expr_kind::Var: case expr_kind::Constant: case expr_kind::Type: case expr_kind::Value:
return save_result(a, copy(a), sh);
case expr_kind::App: {
buffer<expr> new_args;
for (expr const & old_arg : args(a))
new_args.push_back(apply(old_arg));
return save_result(a, mk_app(new_args), sh);
}
case expr_kind::HEq: return save_result(a, mk_heq(apply(heq_lhs(a)), apply(heq_rhs(a))), sh);
case expr_kind::Pair: return save_result(a, mk_pair(apply(pair_first(a)), apply(pair_second(a)), apply(pair_type(a))), sh);
case expr_kind::Proj: return save_result(a, mk_proj(proj_first(a), apply(proj_arg(a))), sh);
case expr_kind::Lambda: return save_result(a, mk_lambda(abst_name(a), apply(abst_domain(a)), apply(abst_body(a))), sh);
case expr_kind::Pi: return save_result(a, mk_pi(abst_name(a), apply(abst_domain(a)), apply(abst_body(a))), sh);
case expr_kind::Sigma: return save_result(a, mk_sigma(abst_name(a), apply(abst_domain(a)), apply(abst_body(a))), sh);
case expr_kind::Let: return save_result(a, mk_let(let_name(a), apply(let_type(a)), apply(let_value(a)), apply(let_body(a))), sh);
case expr_kind::MetaVar:
return save_result(a,
update_metavar(a, [&](local_entry const & e) -> local_entry {
if (e.is_inst())
return mk_inst(e.s(), apply(e.v()));
else
return e;
}),
sh);
}
lean_unreachable(); // LCOV_EXCL_LINE
}
