bool parameter() {
std::size_t old_stack_size = stack_.size();
if (T::match(*this)) {
reduce_stack(stack_.size() - old_stack_size);
return true;
} else
return false;
}
std::string rev_regex(const std::string &rx_, const lexertl::state_machine &sm_)
{
std::string str_;
std::string curr_;
token_stack stack_;
lexertl::citerator iter_(rx_.c_str(), rx_.c_str() + rx_.length(), sm_);
lexertl::citerator end_;
std::size_t parens_ = 0;
for (; iter_ != end_; ++iter_)
{
switch (iter_->id)
{
case eCharset:
case eMacro:
case eComment:
stack_.push(token_pair((eToken)iter_->id, iter_->str()));
break;
case eString:
{
lexertl::citerator i_(iter_->start + 1, iter_->end - 1, sm_);
lexertl::citerator e_;
std::string str_;
for (; i_ != e_; ++i_)
{
str_ = i_->str() + str_;
}
str_ = '"' + str_ + '"';
stack_.push(token_pair((eToken)iter_->id, str_));
break;
}
case eQuantifier:
if (stack_.empty())
{
throw std::runtime_error("Quantifier without regex.");
}
stack_.top().second += iter_->str();
break;
case eDifference:
if (stack_.empty())
{
throw std::runtime_error("Difference without regex.");
}
stack_.top().second += iter_->str();
++iter_;
stack_.top().second += iter_->str();
break;
case eBOL:
// Reverse to eEOL
stack_.push(token_pair(eEOL, std::string(1, '$')));
break;
case eEOL:
// Reverse to eBOL
stack_.push(token_pair(eBOL, std::string(1, '^')));
break;
case eOr:
reduce_stack(stack_);
stack_.push(token_pair((eToken)iter_->id, iter_->str()));
break;
case eOpen:
stack_.push(token_pair((eToken)iter_->id, iter_->str()));
++parens_;
break;
case eClose:
{
if (parens_ < 1)
{
throw std::runtime_error("Unbalanced parens in regex.");
}
std::string str_;
reduce_stack(stack_);
str_ = stack_.top().second;
str_ += iter_->str();
stack_.pop();
stack_.top().second += str_;
stack_.top().first = eCharset;
--parens_;
break;
}
default:
throw std::runtime_error("Unknown regex token.");
break;
}
}
for (; !stack_.empty(); stack_.pop())
{
str_ += stack_.top().second;
}
return str_;
}
