927 lines
28 KiB
C++

// parser.hpp
// Copyright (c) 2005-2018 Ben Hanson (http://www.benhanson.net/)
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file licence_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
#ifndef LEXERTL_PARSER_HPP
#define LEXERTL_PARSER_HPP
#include <assert.h>
#include <algorithm>
#include "tree/end_node.hpp"
#include "tree/iteration_node.hpp"
#include "tree/leaf_node.hpp"
#include <map>
#include "tokeniser/re_tokeniser.hpp"
#include "../runtime_error.hpp"
#include "tree/selection_node.hpp"
#include "tree/sequence_node.hpp"
#include <type_traits>
#include <vector>
namespace lexertl
{
namespace detail
{
/*
General principles of regex parsing:
- Every regex is a sequence of sub-regexes.
- Regexes consist of operands and operators
- All operators decompose to sequence, selection ('|') and iteration ('*')
- Regex tokens are stored on a stack.
- When a complete sequence of regex tokens is on the stack it is processed.
Grammar:
<REGEX> -> <OREXP>
<OREXP> -> <SEQUENCE> | <OREXP>'|'<SEQUENCE>
<SEQUENCE> -> <SUB>
<SUB> -> <EXPRESSION> | <SUB><EXPRESSION>
<EXPRESSION> -> <REPEAT>
<REPEAT> -> charset | macro | '('<REGEX>')' | <REPEAT><DUPLICATE>
<DUPLICATE> -> '?' | '??' | '*' | '*?' | '+' | '+?' | '{n[,[m]]}' |
'{n[,[m]]}?'
*/
template<typename rules_char_type, typename sm_traits>
class basic_parser
{
public:
enum {char_24_bit = sm_traits::char_24_bit};
using char_type = typename sm_traits::char_type;
using id_type = typename sm_traits::id_type;
using end_node = basic_end_node<id_type>;
using input_char_type = typename sm_traits::input_char_type;
using input_string_token = basic_string_token<input_char_type>;
using iteration_node = basic_iteration_node<id_type>;
using leaf_node = basic_leaf_node<id_type>;
using tokeniser =
basic_re_tokeniser<rules_char_type, input_char_type, id_type>;
using node = basic_node<id_type>;
using node_ptr_vector = typename node::node_ptr_vector;
using string = std::basic_string<rules_char_type>;
using string_token = basic_string_token<char_type>;
using selection_node = basic_selection_node<id_type>;
using sequence_node = basic_sequence_node<id_type>;
using charset_map = std::map<string_token, id_type>;
using charset_pair = std::pair<string_token, id_type>;
using compressed = std::integral_constant<bool, sm_traits::compressed>;
using token = basic_re_token<rules_char_type, input_char_type>;
static_assert(std::is_move_assignable<token>::value &&
std::is_move_constructible<token>::value,
"token is not movable.");
using token_vector = std::vector<token>;
basic_parser(const std::locale &locale_,
node_ptr_vector &node_ptr_vector_,
charset_map &charset_map_, const id_type eoi_) :
_locale(locale_),
_node_ptr_vector(node_ptr_vector_),
_charset_map(charset_map_),
_eoi(eoi_),
_token_stack(),
_tree_node_stack()
{
}
observer_ptr<node> parse(const token_vector &regex_, const id_type id_,
const id_type user_id_, const id_type next_dfa_,
const id_type push_dfa_, const bool pop_dfa_,
const std::size_t flags_, id_type &nl_id_, const bool seen_bol_)
{
auto iter_ = regex_.cbegin();
auto end_ = regex_.cend();
observer_ptr<node> root_ = nullptr;
observer_ptr<token> lhs_token_ = nullptr;
// There cannot be less than 2 tokens
auto rhs_token_ = std::make_unique<token>(*iter_++);
char action_ = 0;
_token_stack.emplace(std::move(rhs_token_));
rhs_token_ = std::make_unique<token>(*iter_);
if (iter_ + 1 != end_) ++iter_;
do
{
lhs_token_ = _token_stack.top().get();
action_ = lhs_token_->precedence(rhs_token_->_type);
switch (action_)
{
case '<':
case '=':
_token_stack.emplace(std::move(rhs_token_));
rhs_token_ = std::make_unique<token>(*iter_);
if (iter_ + 1 != end_) ++iter_;
break;
case '>':
reduce(nl_id_);
break;
default:
{
std::ostringstream ss_;
ss_ << "A syntax error occurred: '" <<
lhs_token_->precedence_string() <<
"' against '" << rhs_token_->precedence_string() <<
" in rule id " << id_ << '.';
throw runtime_error(ss_.str());
break;
}
}
} while (!_token_stack.empty());
if (_tree_node_stack.empty())
{
std::ostringstream ss_;
ss_ << "Empty rules are not allowed in rule id " <<
id_ << '.';
throw runtime_error(ss_.str());
}
assert(_tree_node_stack.size() == 1);
observer_ptr<node> lhs_node_ = _tree_node_stack.top();
_tree_node_stack.pop();
_node_ptr_vector.emplace_back(std::make_unique<end_node>
(id_, user_id_, next_dfa_, push_dfa_, pop_dfa_));
observer_ptr<node> rhs_node_ = _node_ptr_vector.back().get();
_node_ptr_vector.emplace_back(std::make_unique<sequence_node>
(lhs_node_, rhs_node_));
root_ = _node_ptr_vector.back().get();
if (seen_bol_)
{
fixup_bol(root_);
}
if ((flags_ & match_zero_len) == 0)
{
const auto &firstpos_ = root_->firstpos();
for (observer_ptr<const node> node_ : firstpos_)
{
if (node_->end_state())
{
std::ostringstream ss_;
ss_ << "Rules that match zero characters are not allowed "
"as this can cause an infinite loop in user code. The "
"match_zero_len flag overrides this check. Rule id " <<
id_ << '.';
throw runtime_error(ss_.str());
}
}
}
return root_;
}
static id_type bol_token()
{
return static_cast<id_type>(~1);
}
static id_type eol_token()
{
return static_cast<id_type>(~2);
}
private:
using input_range = typename input_string_token::range;
using range = typename string_token::range;
using string_token_vector = std::vector<std::unique_ptr<string_token>>;
using token_stack = std::stack<std::unique_ptr<token>>;
using tree_node_stack = typename node::node_stack;
const std::locale &_locale;
node_ptr_vector &_node_ptr_vector;
charset_map &_charset_map;
id_type _eoi;
token_stack _token_stack;
tree_node_stack _tree_node_stack;
void reduce(id_type &nl_id_)
{
observer_ptr<token> lhs_ = nullptr;
observer_ptr<token> rhs_ = nullptr;
token_stack handle_;
char action_ = 0;
do
{
handle_.emplace();
rhs_ = _token_stack.top().release();
handle_.top().reset(rhs_);
_token_stack.pop();
if (!_token_stack.empty())
{
lhs_ = _token_stack.top().get();
action_ = lhs_->precedence(rhs_->_type);
}
} while (!_token_stack.empty() && action_ == '=');
assert(_token_stack.empty() || action_ == '<');
switch (rhs_->_type)
{
case BEGIN:
// finished processing so exit
break;
case REGEX:
// finished parsing, nothing to do
break;
case OREXP:
orexp(handle_);
break;
case SEQUENCE:
_token_stack.emplace(std::make_unique<token>(OREXP));
break;
case SUB:
sub(handle_);
break;
case EXPRESSION:
_token_stack.emplace(std::make_unique<token>(SUB));
break;
case REPEAT:
repeat(handle_);
break;
case BOL:
bol(handle_);
break;
case EOL:
eol(handle_, nl_id_);
break;
case CHARSET:
charset(handle_, compressed());
break;
case OPENPAREN:
openparen(handle_);
break;
case OPT:
case AOPT:
optional(rhs_->_type == OPT);
_token_stack.emplace(std::make_unique<token>(DUP));
break;
case ZEROORMORE:
case AZEROORMORE:
zero_or_more(rhs_->_type == ZEROORMORE);
_token_stack.emplace(std::make_unique<token>(DUP));
break;
case ONEORMORE:
case AONEORMORE:
one_or_more(rhs_->_type == ONEORMORE);
_token_stack.emplace(std::make_unique<token>(DUP));
break;
case REPEATN:
case AREPEATN:
repeatn(rhs_->_type == REPEATN, handle_.top().get());
_token_stack.emplace(std::make_unique<token>(DUP));
break;
default:
throw runtime_error
("Internal error in regex_parser::reduce.");
break;
}
}
void orexp(token_stack &handle_)
{
assert(handle_.top()->_type == OREXP &&
(handle_.size() == 1 || handle_.size() == 3));
if (handle_.size() == 1)
{
_token_stack.emplace(std::make_unique<token>(REGEX));
}
else
{
handle_.pop();
assert(handle_.top()->_type == OR);
handle_.pop();
assert(handle_.top()->_type == SEQUENCE);
perform_or();
_token_stack.emplace(std::make_unique<token>(OREXP));
}
}
void perform_or()
{
// perform or
observer_ptr<node> rhs_ = _tree_node_stack.top();
_tree_node_stack.pop();
observer_ptr<node> lhs_ = _tree_node_stack.top();
_node_ptr_vector.emplace_back
(std::make_unique<selection_node>(lhs_, rhs_));
_tree_node_stack.top() = _node_ptr_vector.back().get();
}
void sub(token_stack &handle_)
{
assert((handle_.top()->_type == SUB &&
handle_.size() == 1) || handle_.size() == 2);
if (handle_.size() == 1)
{
_token_stack.emplace(std::make_unique<token>(SEQUENCE));
}
else
{
handle_.pop();
assert(handle_.top()->_type == EXPRESSION);
// perform join
sequence();
_token_stack.emplace(std::make_unique<token>(SUB));
}
}
void repeat(token_stack &handle_)
{
assert(handle_.top()->_type == REPEAT &&
handle_.size() >= 1 && handle_.size() <= 3);
if (handle_.size() == 1)
{
_token_stack.emplace(std::make_unique<token>(EXPRESSION));
}
else
{
handle_.pop();
assert(handle_.top()->_type == DUP);
_token_stack.emplace(std::make_unique<token>(REPEAT));
}
}
#ifndef NDEBUG
void bol(token_stack &handle_)
#else
void bol(token_stack &)
#endif
{
assert(handle_.top()->_type == BOL &&
handle_.size() == 1);
// store charset
_node_ptr_vector.emplace_back
(std::make_unique<leaf_node>(bol_token(), true));
_tree_node_stack.push(_node_ptr_vector.back().get());
_token_stack.emplace(std::make_unique<token>(REPEAT));
}
#ifndef NDEBUG
void eol(token_stack &handle_, id_type &nl_id_)
#else
void eol(token_stack &, id_type &nl_id_)
#endif
{
const string_token nl_('\n');
const id_type temp_nl_id_ = lookup(nl_);
assert(handle_.top()->_type == EOL &&
handle_.size() == 1);
if (temp_nl_id_ != ~static_cast<id_type>(0))
{
nl_id_ = temp_nl_id_;
}
// store charset
_node_ptr_vector.emplace_back
(std::make_unique<leaf_node>(eol_token(), true));
_tree_node_stack.push(_node_ptr_vector.back().get());
_token_stack.emplace(std::make_unique<token>(REPEAT));
}
// Uncompressed
void charset(token_stack &handle_, const std::false_type &)
{
assert(handle_.top()->_type == CHARSET &&
handle_.size() == 1);
const id_type id_ = lookup(handle_.top()->_str);
// store charset
_node_ptr_vector.emplace_back(std::make_unique<leaf_node>(id_, true));
_tree_node_stack.push(_node_ptr_vector.back().get());
_token_stack.emplace(std::make_unique<token>(REPEAT));
}
// Compressed
void charset(token_stack &handle_, const std::true_type &)
{
assert(handle_.top()->_type == CHARSET &&
handle_.size() == 1);
std::unique_ptr<token> token_(handle_.top().release());
handle_.pop();
create_sequence(token_);
}
// Slice wchar_t into sequence of char.
void create_sequence(std::unique_ptr<token> &token_)
{
string_token_vector data_[char_24_bit ? 3 : 2];
for (const input_range &range_ : token_->_str._ranges)
{
slice_range(range_, data_,
std::integral_constant<bool, char_24_bit>());
}
push_ranges(data_, std::integral_constant<bool, char_24_bit>());
_token_stack.emplace(std::make_unique<token>(OPENPAREN));
_token_stack.emplace(std::make_unique<token>(REGEX));
_token_stack.emplace(std::make_unique<token>(CLOSEPAREN));
}
// 16 bit unicode
void slice_range(const input_range &range_, string_token_vector data_[2],
const std::false_type &)
{
const unsigned char first_msb_ = static_cast<unsigned char>
((range_.first >> 8) & 0xff);
const unsigned char first_lsb_ = static_cast<unsigned char>
(range_.first & 0xff);
const unsigned char second_msb_ = static_cast<unsigned char>
((range_.second >> 8) & 0xff);
const unsigned char second_lsb_ = static_cast<unsigned char>
(range_.second & 0xff);
if (first_msb_ == second_msb_)
{
insert_range(first_msb_, first_msb_, first_lsb_,
second_lsb_, data_);
}
else
{
insert_range(first_msb_, first_msb_, first_lsb_, 0xff, data_);
if (second_msb_ > first_msb_ + 1)
{
insert_range(first_msb_ + 1, second_msb_ - 1, 0, 0xff, data_);
}
insert_range(second_msb_, second_msb_, 0, second_lsb_, data_);
}
}
// 24 bit unicode
void slice_range(const input_range &range_, string_token_vector data_[3],
const std::true_type &)
{
const unsigned char first_msb_ = static_cast<unsigned char>
((range_.first >> 16) & 0xff);
const unsigned char first_mid_ = static_cast<unsigned char>
((range_.first >> 8) & 0xff);
const unsigned char first_lsb_ = static_cast<unsigned char>
(range_.first & 0xff);
const unsigned char second_msb_ = static_cast<unsigned char>
((range_.second >> 16) & 0xff);
const unsigned char second_mid_ = static_cast<unsigned char>
((range_.second >> 8) & 0xff);
const unsigned char second_lsb_ = static_cast<unsigned char>
(range_.second & 0xff);
if (first_msb_ == second_msb_)
{
string_token_vector data2_[2];
// Re-use 16 bit slice function
slice_range(range_, data2_, std::false_type());
for (std::size_t i_ = 0, size_ = data2_[0].size();
i_ < size_; ++i_)
{
insert_range(string_token(first_msb_, first_msb_),
*data2_[0][i_], *data2_[1][i_], data_);
}
}
else
{
insert_range(first_msb_, first_msb_,
first_mid_, first_mid_,
first_lsb_, 0xff, data_);
if (first_mid_ != 0xff)
{
insert_range(first_msb_, first_msb_,
first_mid_ + 1, 0xff,
0, 0xff, data_);
}
if (second_msb_ > first_msb_ + 1)
{
insert_range(first_mid_ + 1, second_mid_ - 1,
0, 0xff,
0, 0xff, data_);
}
if (second_mid_ != 0)
{
insert_range(second_msb_, second_msb_,
0, second_mid_ - 1,
0, 0xff, data_);
insert_range(second_msb_, second_msb_,
second_mid_, second_mid_,
0, second_lsb_, data_);
}
else
{
insert_range(second_msb_, second_msb_,
0, second_mid_,
0, second_lsb_, data_);
}
}
}
// 16 bit unicode
void insert_range(const unsigned char first_, const unsigned char second_,
const unsigned char first2_, const unsigned char second2_,
string_token_vector data_[2])
{
const string_token token_(first_ > second_ ? second_ : first_,
first_ > second_ ? first_ : second_);
const string_token token2_(first2_ > second2_ ? second2_ : first2_,
first2_ > second2_ ? first2_ : second2_);
insert_range(token_, token2_, data_);
}
void insert_range(const string_token &token_, const string_token &token2_,
string_token_vector data_[2])
{
typename string_token_vector::const_iterator iter_ =
std::find_if(data_[0].begin(), data_[0].end(),
[&token_](const std::unique_ptr<string_token> &rhs_)
{
return token_ == *rhs_.get();
});
if (iter_ == data_[0].end())
{
data_[0].emplace_back(std::make_unique<string_token>(token_));
data_[1].emplace_back(std::make_unique<string_token>(token2_));
}
else
{
const std::size_t index_ = iter_ - data_[0].begin();
data_[1][index_]->insert(token2_);
}
}
// 24 bit unicode
void insert_range(const unsigned char first_, const unsigned char second_,
const unsigned char first2_, const unsigned char second2_,
const unsigned char first3_, const unsigned char second3_,
string_token_vector data_[3])
{
const string_token token_(first_ > second_ ? second_ : first_,
first_ > second_ ? first_ : second_);
const string_token token2_(first2_ > second2_ ? second2_ : first2_,
first2_ > second2_ ? first2_ : second2_);
const string_token token3_(first3_ > second3_ ? second3_ : first3_,
first3_ > second3_ ? first3_ : second3_);
insert_range(token_, token2_, token3_, data_);
}
void insert_range(const string_token &token_, const string_token &token2_,
const string_token &token3_, string_token_vector data_[3])
{
auto iter_ = data_[0].cbegin();
auto end_ = data_[0].cend();
bool finished_ = false;
do
{
iter_ = std::find_if(iter_, end_,
[&token_](const std::unique_ptr<string_token> &rhs_)
{
return token_ == *rhs_.get();
});
if (iter_ == end_)
{
data_[0].emplace_back(std::make_unique<string_token>(token_));
data_[1].emplace_back(std::make_unique<string_token>(token2_));
data_[2].emplace_back(std::make_unique<string_token>(token3_));
finished_ = true;
}
else
{
const std::size_t index_ = iter_ - data_[0].begin();
if (*data_[1][index_] == token2_)
{
data_[2][index_]->insert(token3_);
finished_ = true;
}
else
{
++iter_;
}
}
} while (!finished_);
}
// 16 bit unicode
void push_ranges(string_token_vector data_[2], const std::false_type &)
{
auto viter_ = data_[0].cbegin();
auto vend_ = data_[0].cend();
auto viter2_ = data_[1].cbegin();
push_range(viter_++->get());
push_range(viter2_++->get());
sequence();
while (viter_ != vend_)
{
push_range(viter_++->get());
push_range(viter2_++->get());
sequence();
perform_or();
}
}
// 24 bit unicode
void push_ranges(string_token_vector data_[3], const std::true_type &)
{
auto viter_ = data_[0].cbegin();
auto vend_ = data_[0].cend();
auto viter2_ = data_[1].cbegin();
auto viter3_ = data_[2].cbegin();
push_range(viter_++->get());
push_range(viter2_++->get());
sequence();
push_range(viter3_++->get());
sequence();
while (viter_ != vend_)
{
push_range(viter_++->get());
push_range(viter2_++->get());
sequence();
push_range(viter3_++->get());
sequence();
perform_or();
}
}
void push_range(observer_ptr<const string_token> token_)
{
const id_type id_ = lookup(*token_);
_node_ptr_vector.emplace_back(std::make_unique<leaf_node>(id_, true));
_tree_node_stack.push(_node_ptr_vector.back().get());
}
id_type lookup(const string_token &charset_)
{
// Converted to id_type below.
std::size_t id_ = sm_traits::npos();
if (static_cast<id_type>(id_) < id_)
{
throw runtime_error("id_type is not large enough "
"to hold all ids.");
}
typename charset_map::const_iterator iter_ =
_charset_map.find(charset_);
if (iter_ == _charset_map.end())
{
id_ = _charset_map.size();
_charset_map.insert(charset_pair(charset_,
static_cast<id_type>(id_)));
}
else
{
id_ = iter_->second;
}
return static_cast<id_type>(id_);
}
void openparen(token_stack &handle_)
{
assert(handle_.top()->_type == OPENPAREN &&
handle_.size() == 3);
handle_.pop();
assert(handle_.top()->_type == REGEX);
handle_.pop();
assert(handle_.top()->_type == CLOSEPAREN);
_token_stack.emplace(std::make_unique<token>(REPEAT));
}
void sequence()
{
observer_ptr<node> rhs_ = _tree_node_stack.top();
_tree_node_stack.pop();
observer_ptr<node> lhs_ = _tree_node_stack.top();
_node_ptr_vector.emplace_back
(std::make_unique<sequence_node>(lhs_, rhs_));
_tree_node_stack.top() = _node_ptr_vector.back().get();
}
void optional(const bool greedy_)
{
// perform ?
observer_ptr<node> lhs_ = _tree_node_stack.top();
// Don't know if lhs_ is a leaf_node, so get firstpos.
auto &firstpos_ = lhs_->firstpos();
for (observer_ptr<node> node_ : firstpos_)
{
// These are leaf_nodes!
node_->greedy(greedy_);
}
_node_ptr_vector.emplace_back(std::make_unique<leaf_node>
(node::null_token(), greedy_));
observer_ptr<node> rhs_ = _node_ptr_vector.back().get();
_node_ptr_vector.emplace_back
(std::make_unique<selection_node>(lhs_, rhs_));
_tree_node_stack.top() = _node_ptr_vector.back().get();
}
void zero_or_more(const bool greedy_)
{
// perform *
observer_ptr<node> ptr_ = _tree_node_stack.top();
_node_ptr_vector.emplace_back
(std::make_unique<iteration_node>(ptr_, greedy_));
_tree_node_stack.top() = _node_ptr_vector.back().get();
}
void one_or_more(const bool greedy_)
{
// perform +
observer_ptr<node> lhs_ = _tree_node_stack.top();
observer_ptr<node> copy_ = lhs_->copy(_node_ptr_vector);
_node_ptr_vector.emplace_back(std::make_unique<iteration_node>
(copy_, greedy_));
observer_ptr<node> rhs_ = _node_ptr_vector.back().get();
_node_ptr_vector.emplace_back
(std::make_unique<sequence_node>(lhs_, rhs_));
_tree_node_stack.top() = _node_ptr_vector.back().get();
}
// perform {n[,[m]]}
// Semantic checks have already been performed.
// {0,} = *
// {0,1} = ?
// {1,} = +
// therefore we do not check for these cases.
void repeatn(const bool greedy_, observer_ptr<const token> token_)
{
const rules_char_type *str_ = token_->_extra.c_str();
std::size_t min_ = 0;
bool comma_ = false;
std::size_t max_ = 0;
while (*str_>= '0' && *str_ <= '9')
{
min_ *= 10;
min_ += *str_ - '0';
++str_;
}
comma_ = *str_ == ',';
if (comma_) ++str_;
while (*str_>= '0' && *str_ <= '9')
{
max_ *= 10;
max_ += *str_ - '0';
++str_;
}
if (!(min_ == 1 && !comma_))
{
const std::size_t top_ = min_ > 0 ? min_ : max_;
if (min_ == 0)
{
optional(greedy_);
}
observer_ptr<node> prev_ = _tree_node_stack.top()->
copy(_node_ptr_vector);
observer_ptr<node> curr_ = nullptr;
for (std::size_t i_ = 2; i_ < top_; ++i_)
{
curr_ = prev_->copy(_node_ptr_vector);
_tree_node_stack.push(prev_);
sequence();
prev_ = curr_;
}
if (comma_ && min_ > 0)
{
if (min_ > 1)
{
curr_ = prev_->copy(_node_ptr_vector);
_tree_node_stack.push(prev_);
sequence();
prev_ = curr_;
}
if (comma_ && max_)
{
_tree_node_stack.push(prev_);
optional(greedy_);
prev_ = _tree_node_stack.top();
_tree_node_stack.pop();
const std::size_t count_ = max_ - min_;
for (std::size_t i_ = 1; i_ < count_; ++i_)
{
curr_ = prev_->copy(_node_ptr_vector);
_tree_node_stack.push(prev_);
sequence();
prev_ = curr_;
}
}
else
{
_tree_node_stack.push(prev_);
zero_or_more(greedy_);
prev_ = _tree_node_stack.top();
_tree_node_stack.pop();
}
}
_tree_node_stack.push(prev_);
sequence();
}
}
void fixup_bol(observer_ptr<node> &root_)const
{
const auto &first_ = root_->firstpos();
bool found_ = false;
for (observer_ptr<const node> node_ : first_)
{
found_ = !node_->end_state() && node_->token() == bol_token();
if (found_) break;
}
if (!found_)
{
_node_ptr_vector.emplace_back
(std::make_unique<leaf_node>(bol_token(), true));
observer_ptr<node> lhs_ = _node_ptr_vector.back().get();
_node_ptr_vector.emplace_back
(std::make_unique<leaf_node>(node::null_token(), true));
observer_ptr<node> rhs_ = _node_ptr_vector.back().get();
_node_ptr_vector.emplace_back
(std::make_unique<selection_node>(lhs_, rhs_));
lhs_ = _node_ptr_vector.back().get();
_node_ptr_vector.emplace_back
(std::make_unique<sequence_node>(lhs_, root_));
root_ = _node_ptr_vector.back().get();
}
}
};
}
}
#endif