X3:如何创建解析器以进行集中读取

X3: How to create parser to read in sets?

本文关键字：读取 集中 何创建 创建 X3      更新时间：2023-10-16

如何创建一个读取3组整数的规则。即…

1 2 3                   OK, 1 set of 3 ints
1 2 3 4 5 6             OK, 2 sets of 3 ints
1 2 3 4 5               ERROR, 1 set of 3 ints, 1 short for 2nd
1 2 3 4 5 6 7 8 9       OK, 3 sets of 3 ints
1 2 3 4 5 6 7 8 9 10    ERROR, 3 sets of 3 ints, 1 short for 4th

我对fusion adapt结构有问题(如何使args的数量可变(。。。

BOOST_FUSION_ADAPT_STRUCT(client::ast::number, n1, n2, n3, n4, n5, n6)

不知道为什么这个规则不起作用。

... = *(int_ >> int_ >> int_);

这是我的尝试。。。http://coliru.stacked-crooked.com/a/cb10e8096c95fc55

//#define BOOST_SPIRIT_X3_DEBUG
#include <iostream>
#include <boost/spirit/home/x3.hpp>
#include <boost/fusion/include/adapt_struct.hpp>
#include <boost/fusion/include/io.hpp>
namespace client { 
namespace ast {
struct number {
int n1, n2, n3, n4, n5, n6;
};
struct comment {
std::string text;
bool dummy;
};
struct input {
std::vector<comment> comments;  
std::vector<number> numbers;
};
} 
}
BOOST_FUSION_ADAPT_STRUCT(client::ast::comment, text, dummy)
BOOST_FUSION_ADAPT_STRUCT(client::ast::number, n1, n2, n3) // , n4, n5, n6) error
BOOST_FUSION_ADAPT_STRUCT(client::ast::input, comments, numbers)
namespace client {      
namespace parser {
namespace x3 = boost::spirit::x3;
using namespace x3;
typedef std::string::const_iterator It;
using namespace x3;
auto const comment = rule<struct _c, ast::comment> {"comment"} = lexeme[*(char_ - eol)] >> attr(false);
auto const number  = rule<struct _n, ast::number> {"number"}   = int_ >> int_ >> int_;
// auto const number  = rule<struct _n, ast::number> {"number"}   = *(int_ >> int_ >> int_); error
auto lines = [](auto p) { return *(p >> eol); };
auto const input = 
repeat(1)[comment] >> eol >>
lines(number);
}
}
int main() {
namespace x3 = boost::spirit::x3;
std::string const iss("any char string heren1 2 3n1 2 3 4 5 6");
auto iter = iss.begin(), eof = iss.end();
client::ast::input types;
bool ok = phrase_parse(iter, eof, client::parser::input, x3::blank, types);
if (iter != eof) {
std::cout << "Remaining unparsed: '" << std::string(iter, eof) << "'n";
}
std::cout << "Parsed: " << (100.0 * std::distance(iss.begin(), iter) / iss.size()) << "%n";
std::cout << "ok = " << ok << std::endl;
for (auto& item : types.comments) { std::cout << "comment: " << boost::fusion::as_deque(item) << "n"; }
for (auto& item : types.numbers)  { std::cout << "number:  " << boost::fusion::as_deque(item) << "n"; }
}

打印

Parsed: 71.0526%
ok = 1
comment: (any char string here 0)
number:  (1 2 3)

算子Kleene-star合成为容器属性(文档显示：vector<T>(

结构体number不是容器属性。所以。

此外，我完全不清楚你想要实现什么。你的结构应该是6int，但你想解析3的组吗？组的是什么意思？我可能会这么做：

struct number {
struct group { int n1, n2, n3; };
std::vector<group> groups;
};
BOOST_FUSION_ADAPT_STRUCT(client::ast::number::group, n1, n2, n3)
BOOST_FUSION_ADAPT_STRUCT(client::ast::number, groups)

这与语法分析器表达式兼容

*(int_ >> int_ >> int_)

现场演示

两个注意事项：

  1. 再次需要伪attibute(考虑using number = std::vector<number_group>;(
  2. 输入结束时缺少n(考虑eol | eoi(

Coliru

//#define BOOST_SPIRIT_X3_DEBUG
#include <iostream>
#include <boost/spirit/home/x3.hpp>
#include <boost/fusion/include/adapt_struct.hpp>
#include <boost/fusion/include/io.hpp>
namespace client { 
namespace ast {
struct number {
struct group { int n1, n2, n3; };
std::vector<group> groups;
bool dummy;
};
struct comment {
std::string text;
bool dummy;
};
struct input {
std::vector<comment> comments;  
std::vector<number> numbers;
};
} 
}
BOOST_FUSION_ADAPT_STRUCT(client::ast::comment, text, dummy)
BOOST_FUSION_ADAPT_STRUCT(client::ast::number::group, n1, n2, n3)
BOOST_FUSION_ADAPT_STRUCT(client::ast::number, groups, dummy)
BOOST_FUSION_ADAPT_STRUCT(client::ast::input, comments, numbers)
namespace client {      
namespace parser {
namespace x3 = boost::spirit::x3;
using namespace x3;
typedef std::string::const_iterator It;
using namespace x3;
auto const comment = rule<struct _c, ast::comment> {"comment"} = lexeme[*(char_ - eol)] >> attr(false);
auto const number  = rule<struct _n, ast::number> {"number"}   = *(int_ >> int_ >> int_) >> attr(false);
auto lines = [](auto p) { return *(p >> eol); };
auto const input = 
repeat(1)[comment] >> eol >>
lines(number);
}
}
int main() {
namespace x3 = boost::spirit::x3;
std::string const iss("any char string heren1 2 3n1 2 3 4 5 6n");
auto iter = iss.begin(), eof = iss.end();
client::ast::input types;
bool ok = phrase_parse(iter, eof, client::parser::input, x3::blank, types);
if (iter != eof) {
std::cout << "Remaining unparsed: '" << std::string(iter, eof) << "'n";
}
std::cout << "Parsed: " << (100.0 * std::distance(iss.begin(), iter) / iss.size()) << "%n";
std::cout << "ok = " << ok << std::endl;
for (auto &item : types.comments) {
std::cout << "comment: " << boost::fusion::as_deque(item) << "n";
}
for (auto& item : types.numbers) {
std::cout << "number:  ";
for (auto& g : item.groups)
std::cout << boost::fusion::as_deque(g) << " ";
std::cout << "n";
}
}

打印

Parsed: 100%
ok = 1
comment: (any char string here 0)
number:  (1 2 3) 
number:  (1 2 3) (4 5 6)
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