I want use Boost.Spirit.Lex to lex a binary file; for this purpose I wrote the following program (here is an extract):
#include <boost/spirit/include/lex_lexertl.hpp>
#include <boost/spirit/include/support_multi_pass.hpp>
#include <boost/bind.hpp>
#include <boost/ref.hpp>
#include <fstream>
#include <iterator>
#include <string>
namespace spirit = boost::spirit;
namespace lex = spirit::lex;
#define X 1
#define Y 2
#define Z 3
template<typename L>
class word_count_tokens : public lex::lexer<L>
{
public:
word_count_tokens () {
this->self.add
("[^ \t\n]+", X)
("\n", Y)
(".", Z);
}
};
class counter
{
public:
typedef bool result_type;
template<typename T>
bool operator () (const T &t, size_t &c, size_t &w, size_t &l) const {
switch (t.id ()) {
case X:
++w; c += t.value ().size ();
break;
case Y:
++l; ++c;
break;
case Z:
++c;
break;
}
return true;
}
};
int main (int argc, char **argv)
{
std::ifstream ifs (argv[1], std::ios::in | std::ios::binary);
auto first = spirit::make_default_multi_pass (std::istream_iterator<char> (ifs));
auto last = spirit::make_default_multi_pass (std::istream_iterator<char> ());
size_t w, c, l;
word_count_tokens<lex::lexertl::lexer<>> word_count_functor;
w = c = l = 0;
bool r = lex::tokenize (first, last, word_count_functor, boost::bind (counter (), _1, boost::ref (c), boost::ref (w), boost::ref (l)));
ifs.close ();
if (r) {
std::cout << l << ", " << w << ", " << c << std::endl;
}
return 0;
}
The build returns the following error:
lexer.hpp:390:46: error: non-const lvalue reference to type 'const char *' cannot bind to a value of unrelated type
Now, the error is due to definition of concrete lexer, lex::lexer<>
; in fact its first parameter is defaulted to const char *
. I obtain the same error also if I use spirit::istream_iterator
or spirit::make_default_multi_pass (.....)
.
But if I specify the correct template parameters of lex::lexer<>
I obtain a plethora of errors!
Solutions?
Update
I have putted all source file; it's the word_counter site's example.
Okay, since the question was changed, here's a new answer, addressing some points with the complete code sample.
Firstly, you need to use a custom token type. I.e.
word_count_tokens<lex::lexertl::lexer<lex::lexertl::token<boost::spirit::istream_iterator>>> word_count_functor;
// instead of:
// word_count_tokens<lex::lexertl::lexer<>> word_count_functor;
Obviously, it's customary to typedef lex::lexertl::token<boost::spirit::istream_iterator>
You need to use min_token_id
instead of token IDs 1,2,3. Also, make it an enum for ease of maintenance:
enum token_ids {
X = lex::min_token_id + 1,
Y,
Z,
};
You can no longer just use .size()
on the default token value()
since the iterator range is not RandomAccessRange anymore. Instead, employ boost::distance()
which is specialized for iterator_range
:
++w; c += boost::distance(t.value()); // t.value ().size ();
Combining these fixes: Live On Coliru
#include <boost/spirit/include/lex_lexertl.hpp>
#include <boost/spirit/include/support_istream_iterator.hpp>
#include <boost/bind.hpp>
#include <fstream>
namespace spirit = boost::spirit;
namespace lex = spirit::lex;
enum token_ids {
X = lex::min_token_id + 1,
Y,
Z,
};
template<typename L>
class word_count_tokens : public lex::lexer<L>
{
public:
word_count_tokens () {
this->self.add
("[^ \t\n]+", X)
("\n" , Y)
("." , Z);
}
};
struct counter
{
typedef bool result_type;
template<typename T>
bool operator () (const T &t, size_t &c, size_t &w, size_t &l) const {
switch (t.id ()) {
case X:
++w; c += boost::distance(t.value()); // t.value ().size ();
break;
case Y:
++l; ++c;
break;
case Z:
++c;
break;
}
return true;
}
};
int main (int argc, char **argv)
{
std::ifstream ifs (argv[1], std::ios::in | std::ios::binary);
ifs >> std::noskipws;
boost::spirit::istream_iterator first(ifs), last;
word_count_tokens<lex::lexertl::lexer<lex::lexertl::token<boost::spirit::istream_iterator>>> word_count_functor;
size_t w = 0, c = 0, l = 0;
bool r = lex::tokenize (first, last, word_count_functor,
boost::bind (counter (), _1, boost::ref (c), boost::ref (w), boost::ref (l)));
ifs.close ();
if (r) {
std::cout << l << ", " << w << ", " << c << std::endl;
}
}
When run on itself, prints
65, 183, 1665