static int letter_type(const char* liter, size_t len)
{
if (3 == len && is_inst(liter)) {
return TOKEN_INST;
} else if (1 == len) {
if ('A' == liter[0])
return TOKEN_SYMB_A;
else if ('X' == liter[0])
return TOKEN_SYMB_X;
else if ('Y' == liter[0])
return TOKEN_SYMB_Y;
}
return TOKEN_LABEL;
}
bool is_lt(expr const & a, expr const & b, bool use_hash) {
if (is_eqp(a, b)) return false;
unsigned da = get_depth(a);
unsigned db = get_depth(b);
if (da < db) return true;
if (da > db) return false;
if (a.kind() != b.kind()) return a.kind() < b.kind();
if (use_hash) {
if (a.hash() < b.hash()) return true;
if (a.hash() > b.hash()) return false;
}
if (a == b) return false;
if (is_var(a)) return var_idx(a) < var_idx(b);
switch (a.kind()) {
case expr_kind::Var:
lean_unreachable(); // LCOV_EXCL_LINE
case expr_kind::Constant:
return const_name(a) < const_name(b);
case expr_kind::App:
if (num_args(a) != num_args(b))
return num_args(a) < num_args(b);
for (unsigned i = 0; i < num_args(a); i++) {
if (arg(a, i) != arg(b, i))
return is_lt(arg(a, i), arg(b, i), use_hash);
}
lean_unreachable(); // LCOV_EXCL_LINE
case expr_kind::Lambda: // Remark: we ignore get_abs_name because we want alpha-equivalence
case expr_kind::Pi:
if (abst_domain(a) != abst_domain(b))
return is_lt(abst_domain(a), abst_domain(b), use_hash);
else
return is_lt(abst_body(a), abst_body(b), use_hash);
case expr_kind::Type:
return ty_level(a) < ty_level(b);
case expr_kind::Value:
return to_value(a) < to_value(b);
case expr_kind::Let:
if (let_type(a) != let_type(b)) {
return is_lt(let_type(a), let_type(b), use_hash);
} else if (let_value(a) != let_value(b)){
return is_lt(let_value(a), let_value(b), use_hash);
} else {
return is_lt(let_body(a), let_body(b), use_hash);
}
case expr_kind::MetaVar:
if (metavar_name(a) != metavar_name(b)) {
return metavar_name(a) < metavar_name(b);
} else {
auto it1 = metavar_lctx(a).begin();
auto it2 = metavar_lctx(b).begin();
auto end1 = metavar_lctx(a).end();
auto end2 = metavar_lctx(b).end();
for (; it1 != end1 && it2 != end2; ++it1, ++it2) {
if (it1->kind() != it2->kind()) {
return it1->kind() < it2->kind();
} else if (it1->s() != it2->s()) {
return it1->s() < it2->s();
} else if (it1->is_inst()) {
if (it1->v() != it2->v())
return is_lt(it1->v(), it2->v(), use_hash);
} else {
if (it1->n() != it2->n())
return it1->n() < it2->n();
}
}
return it1 == end1 && it2 != end2;
}
}
lean_unreachable(); // LCOV_EXCL_LINE
}