C++ 提升精神模板专业化失败
下面是我试图用boost::spirit::qi编写的语法的一个非常简洁的版本。C++ 提升精神模板专业化失败,c++,boost,boost-spirit,boost-spirit-qi,C++,Boost,Boost Spirit,Boost Spirit Qi,下面是我试图用boost::spirit::qi编写的语法的一个非常简洁的版本。 环境:VS2013、x86、Boost1.64 当包含头文件时,编译器会抱怨行 rBlock = "{" >> +(rInvocation) >> "}"; 日志很长(我只复制了开头和结尾): 多个部分专门化与模板参数列表匹配 … … 请参阅函数模板实例化的参考 '提振::精神::气::规则 &正在编译boost::spirit::qi::rule::operator=>(const Ex
环境:VS2013、x86、Boost1.64
当包含头文件时,编译器会抱怨行
rBlock = "{" >> +(rInvocation) >> "}";
日志很长(我只复制了开头和结尾):
多个部分专门化与模板参数列表匹配
……
请参阅函数模板实例化的参考 '提振::精神::气::规则 &正在编译boost::spirit::qi::rule::operator=>(const Expr&) 我的错在哪里 头文件:
//mygrammar.h
#pragma once
#include <boost/spirit/include/qi.hpp>
namespace myNS
{
typedef std::string Identifier;
typedef ::boost::spirit::qi::rule <const char*, Identifier()> myIdentifierRule;
typedef ::boost::variant<char, int> Expression;
typedef ::boost::spirit::qi::rule <const char*, Expression()> myExpressionRule;
struct IdntifierEqArgument
{
Identifier ident;
Expression arg;
};
typedef ::boost::variant < IdntifierEqArgument, Expression > Argument;
typedef ::boost::spirit::qi::rule <const char*, Argument()> myArgumentRule;
typedef ::std::vector<Argument> ArgumentList;
typedef ::boost::spirit::qi::rule <const char*, myNS::ArgumentList()> myArgumentListRule;
struct Invocation
{
Identifier identifier;
::boost::optional<ArgumentList> args;
};
typedef ::boost::spirit::qi::rule <const char*, Invocation()> myInvocationRule;
typedef ::std::vector<Invocation> Block;
typedef ::boost::spirit::qi::rule <const char*, myNS::Block()> myBlockRule;
}
BOOST_FUSION_ADAPT_STRUCT(
myNS::IdntifierEqArgument,
(auto, ident)
(auto, arg)
);
BOOST_FUSION_ADAPT_STRUCT(
myNS::Invocation,
(auto, identifier)
(auto, args)
);
namespace myNS
{
struct myRules
{
myIdentifierRule rIdentifier;
myExpressionRule rExpression;
myArgumentRule rArgument;
myArgumentListRule rArgumentList;
myInvocationRule rInvocation;
myBlockRule rBlock;
myRules()
{
using namespace ::boost::spirit;
using namespace ::boost::spirit::qi;
rIdentifier = as_string[((qi::alpha | '_') >> *(qi::alnum | '_'))];
rExpression = char_ | int_;
rArgument = (rIdentifier >> "=" >> rExpression) | rExpression;
rArgumentList = rArgument >> *("," >> rArgument);
rInvocation = rIdentifier >> "(" >> -rArgumentList >> ")";
rBlock = "{" >> +(rInvocation) >> "}";
}
};
}
//mygrammar.h
#布拉格语一次
#包括
名称空间myNS
{
typedef std::字符串标识符;
typedef::boost::spirit::qi::rule myIdentifierRule;
typedef::boost::variant表达式;
typedef::boost::spirit::qi::rule myExpressionRule;
结构标识符参数
{
标识符标识符;
表达arg;
};
typedef::boost::variant参数;
typedef::boost::spirit::qi::rule myArgumentRule;
typedef::std::向量参数列表;
typedef::boost::spirit::qi::rule myArgumentListRule;
结构调用
{
标识符;
::boost::可选参数;
};
typedef::boost::spirit::qi::rule myInvocationRule;
typedef::std::向量块;
typedef::boost::spirit::qi::rule myBlockRule;
}
增强融合适应结构(
myNS::IdntifierEqArgument,
(自动,识别)
(自动,arg)
);
增强融合适应结构(
myNS::调用,
(自动,标识符)
(自动,args)
);
名称空间myNS
{
结构myRules
{
桃金娘;
myExpressionRule rExpression;
我的爱是稀有的;
myArgumentListRule rArgumentList;
我的职业;
myBlockRule-rBlock;
myRules()
{
使用名称空间::boost::spirit;
使用名称空间::boost::spirit::qi;
rIdentifier=as_字符串[((qi::alpha |'')>*(qi::alnum |''))];
rExpression=char|int|;
rArgument=(rIdentifier>>“=”>>再加压)|再加压;
rArgumentList=rArgument>>*(“,”>>rArgument);
RINOBIATE=rIdentifier>>“(“>>-rArgumentList>>”);
rBlock=“{”>>+(rinjournal)>>“}”;
}
};
}
我不确定问题是在哪里触发的,但这显然是属性转发规则中存在太多歧义的症状
从概念上讲,这可能是由具有相似/兼容布局的属性类型触发的。在语言理论中,您看到的是C++的命名类型系统与属性传播系统中的结构类型近似之间的不匹配。但足够的理论:)
我不认为attr\u cast
会在这里拯救你,因为它可能在引擎盖下使用相同的机制和启发式
它引起了我的注意,使参数列表
可选是。。。不是很有用(因为空列表已经准确地反映了缺少参数)
所以我试着简化规则:
rArgumentList = -(rArgument % ',');
rInvocation = rIdentifier >> '(' >> rArgumentList >> ')';
声明的属性类型可以是ArgumentList
,而不是boost::optional::ArgumentList
事实证明,当传播到向量时,这会消除歧义,因此。。。你得救了
如果你觉得这是“偶然的”,你应该这样做!如果这不是“偶然”消除了歧义,我会怎么做?我会创建一个语义动作,通过更简单的机制来传播调用。很有可能fusion::push_-back(\u-val,\u-1)
或类似的方法会奏效
另见
回顾和演示
在这里的清理评论中,我介绍了一些修复/改进以及转储解析的AST的测试运行
将AST与解析器分开(您不希望在AST类型中使用qi
。您特别不希望在通用模板库中使用名称空间
指令)
不要在自适应宏中使用auto
。这不是一个功能。相反,因为表面上可以使用C++11,所以可以使用基于C++11(decltype)的宏
BOOST_FUSION_ADAPT_STRUCT(myAST::IdntifierEqArgument, ident,arg);
BOOST_FUSION_ADAPT_STRUCT(myAST::Invocation, identifier,args);
AST处于领先地位(为了清晰起见,更喜欢c++11):
我强烈建议使用这些设施
总之,解析器归结为
namespace myNS {
namespace qi = boost::spirit::qi;
template <typename Iterator = char const*>
struct myRules : qi::grammar<Iterator, myAST::Block()> {
myRules() : myRules::base_type(start) {
rIdentifier = qi::raw [(qi::alpha | '_') >> *(qi::alnum | '_')];
rExpression = qi::alpha | qi::int_;
rArgument = (rIdentifier >> '=' >> rExpression) | rExpression;
rArgumentList = -(rArgument % ',');
rInvocation = rIdentifier >> '(' >> rArgumentList >> ')';
rBlock = '{' >> +rInvocation >> '}';
start = qi::skip(qi::space) [ rBlock ];
BOOST_SPIRIT_DEBUG_NODES((start)(rBlock)(rInvocation)(rIdentifier)(rArgumentList)(rArgument)(rExpression))
}
private:
qi::rule<Iterator, myAST::Block()> start;
using Skipper = qi::space_type;
qi::rule<Iterator, myAST::Argument(), Skipper> rArgument;
qi::rule<Iterator, myAST::ArgumentList(), Skipper> rArgumentList;
qi::rule<Iterator, myAST::Invocation(), Skipper> rInvocation;
qi::rule<Iterator, myAST::Block(), Skipper> rBlock;
// implicit lexemes
qi::rule<Iterator, myAST::Identifier()> rIdentifier;
qi::rule<Iterator, myAST::Expression()> rExpression;
};
}
我会考虑通过将<代码>标识符QualGuangs<代码>重命名为更具表现力的东西,比如<代码>命名参数。按照前一种约定,您可以将Expression命名为AnyLooseCharacterOrIntegralNumber
。很可能很清楚哪个更好,以及为什么:)
//#define BOOST_SPIRIT_DEBUG
BOOST_SPIRIT_DEBUG_NODES((start)(rBlock)(rInvocation)(rIdentifier)(rArgumentList)(rArgument)(rExpression))
namespace myNS {
namespace qi = boost::spirit::qi;
template <typename Iterator = char const*>
struct myRules : qi::grammar<Iterator, myAST::Block()> {
myRules() : myRules::base_type(start) {
rIdentifier = qi::raw [(qi::alpha | '_') >> *(qi::alnum | '_')];
rExpression = qi::alpha | qi::int_;
rArgument = (rIdentifier >> '=' >> rExpression) | rExpression;
rArgumentList = -(rArgument % ',');
rInvocation = rIdentifier >> '(' >> rArgumentList >> ')';
rBlock = '{' >> +rInvocation >> '}';
start = qi::skip(qi::space) [ rBlock ];
BOOST_SPIRIT_DEBUG_NODES((start)(rBlock)(rInvocation)(rIdentifier)(rArgumentList)(rArgument)(rExpression))
}
private:
qi::rule<Iterator, myAST::Block()> start;
using Skipper = qi::space_type;
qi::rule<Iterator, myAST::Argument(), Skipper> rArgument;
qi::rule<Iterator, myAST::ArgumentList(), Skipper> rArgumentList;
qi::rule<Iterator, myAST::Invocation(), Skipper> rInvocation;
qi::rule<Iterator, myAST::Block(), Skipper> rBlock;
// implicit lexemes
qi::rule<Iterator, myAST::Identifier()> rIdentifier;
qi::rule<Iterator, myAST::Expression()> rExpression;
};
}
int main() {
std::string const input = R"(
{
foo()
bar(a, b, 42)
qux(someThing_awful01 = 9)
}
)";
auto f = input.data(), l = f + input.size();
myAST::Block block;
bool ok = parse(f, l, myNS::myRules<>{}, block);
if (ok) {
std::cout << "Parse success\n";
for (auto& invocation : block) {
std::cout << invocation.identifier << "(";
for (auto& arg : invocation.args) std::cout << arg << ",";
std::cout << ")\n";
}
}
else
std::cout << "Parse failed\n";
if (f!=l)
std::cout << "Remaining unparsed input: '" << std::string(f,l) << "'\n";
}
//#define BOOST_SPIRIT_DEBUG
#include <boost/spirit/include/qi.hpp>
namespace myAST {
using Identifier = std::string;
using Expression = boost::variant<char, int>;
struct IdntifierEqArgument {
Identifier ident;
Expression arg;
};
using Argument = boost::variant<IdntifierEqArgument, Expression>;
using ArgumentList = std::vector<Argument>;
struct Invocation {
Identifier identifier;
ArgumentList args;
};
using Block = std::vector<Invocation>;
// for debug printing
static inline std::ostream& operator<<(std::ostream& os, myAST::IdntifierEqArgument const& named) {
return os << named.ident << "=" << named.arg;
}
}
BOOST_FUSION_ADAPT_STRUCT(myAST::IdntifierEqArgument, ident,arg);
BOOST_FUSION_ADAPT_STRUCT(myAST::Invocation, identifier,args);
namespace myNS {
namespace qi = boost::spirit::qi;
template <typename Iterator = char const*>
struct myRules : qi::grammar<Iterator, myAST::Block()> {
myRules() : myRules::base_type(start) {
rIdentifier = qi::raw [(qi::alpha | '_') >> *(qi::alnum | '_')];
rExpression = qi::alpha | qi::int_;
rArgument = (rIdentifier >> '=' >> rExpression) | rExpression;
rArgumentList = -(rArgument % ',');
rInvocation = rIdentifier >> '(' >> rArgumentList >> ')';
rBlock = '{' >> +rInvocation >> '}';
start = qi::skip(qi::space) [ rBlock ];
BOOST_SPIRIT_DEBUG_NODES((start)(rBlock)(rInvocation)(rIdentifier)(rArgumentList)(rArgument)(rExpression))
}
private:
qi::rule<Iterator, myAST::Block()> start;
using Skipper = qi::space_type;
qi::rule<Iterator, myAST::Argument(), Skipper> rArgument;
qi::rule<Iterator, myAST::ArgumentList(), Skipper> rArgumentList;
qi::rule<Iterator, myAST::Invocation(), Skipper> rInvocation;
qi::rule<Iterator, myAST::Block(), Skipper> rBlock;
// implicit lexemes
qi::rule<Iterator, myAST::Identifier()> rIdentifier;
qi::rule<Iterator, myAST::Expression()> rExpression;
};
}
int main() {
std::string const input = R"(
{
foo()
bar(a, b, 42)
qux(someThing_awful01 = 9)
}
)";
auto f = input.data(), l = f + input.size();
myAST::Block block;
bool ok = parse(f, l, myNS::myRules<>{}, block);
if (ok) {
std::cout << "Parse success\n";
for (auto& invocation : block) {
std::cout << invocation.identifier << "(";
for (auto& arg : invocation.args) std::cout << arg << ",";
std::cout << ")\n";
}
}
else
std::cout << "Parse failed\n";
if (f!=l)
std::cout << "Remaining unparsed input: '" << std::string(f,l) << "'\n";
}
Parse success
foo()
bar(a,b,42,)
qux(someThing_awful01=9,)
Remaining unparsed input: '
'