[英]Boost::spirit::qi parser not consuming entire string
我正在為一個簡單的計算器創建語法,但是我很難確定一個特定測試用例無法正常工作的原因。 這是解析器的一個功能示例:
#include <iostream>
#include <vector>
#include <string>
#include <boost/spirit/include/qi.hpp>
#include <boost/spirit/include/qi_char.hpp>
#include <boost/spirit/include/qi_parse.hpp>
#include <boost/spirit/include/phoenix_bind.hpp>
using namespace boost::spirit;
using namespace boost::phoenix;
using std::endl;
using std::cout;
using std::string;
using std::vector;
void fPushOp(const string& op){
cout << "PushOp: " << op << endl;
}
void fPushInt(string& my_str){
cout << "PushInt: " << my_str << endl;
}
template<class Iterator>
struct Calculator : public qi::grammar<Iterator> {
qi::rule<Iterator>
expression, logical_or_expression, logical_and_expression, negate_expression, series_expression,
single_expression, inclusive_or_expression, exclusive_or_expression, and_expression, equality_expression,
relational_expression, shift_expression, additive_expression, multiplicative_expression,
term, complement_factor, factor, number, integer, variable, variable_combo, word, result;
Calculator() : Calculator::base_type(result)
{
number =
lexeme[
qi::as_string[
("0x" >> +qi::char_("0-9a-fA-F"))
| ("0b" >> +qi::char_("0-1"))
| ("0" >> +qi::char_("0-7"))
| +qi::char_("0-9")
] [bind(&fPushInt, qi::_1)]
]
;
complement_factor = number
| ('~' >> number)[bind(&fPushOp, "OP_COMPLEMENT")]
| ('!' >> number)[bind(&fPushOp, "OP_NEGATE")];
;
term = complement_factor
>> *( (".." >> complement_factor)[bind(&fPushOp, "OP_LEGER")]
| ('\\' >> complement_factor)[bind(&fPushOp, "OP_MASK")]
);
multiplicative_expression = term
>> *( ('/' >> term)[bind(&fPushOp, "OP_DIV")]
| ('%' >> term)[bind(&fPushOp, "OP_MOD")]
| ('*' >> term)[bind(&fPushOp, "OP_MUL")]
);
additive_expression = multiplicative_expression
>> *( ('+' >> multiplicative_expression)[bind(&fPushOp, "OP_ADD")]
| ('-' >> multiplicative_expression)[bind(&fPushOp, "OP_SUB")]
);
shift_expression = additive_expression
>> *( (">>" >> additive_expression)[bind(&fPushOp, "OP_SRL")]
| ("<<" >> additive_expression)[bind(&fPushOp, "OP_SLL")]
);
relational_expression = shift_expression
>> *( ('<' >> shift_expression)[bind(&fPushOp, "OP_LT")]
| ('>' >> shift_expression)[bind(&fPushOp, "OP_GT")]
| ("<=" >> shift_expression)[bind(&fPushOp, "OP_LET")]
| (">=" >> shift_expression)[bind(&fPushOp, "OP_GET")]
);
equality_expression = relational_expression
>> *( ("==" >> relational_expression)[bind(&fPushOp, "OP_EQ")]
| ("!=" >> relational_expression)[bind(&fPushOp, "OP_NEQ")]
);
and_expression = equality_expression
>> *(('&' >> equality_expression)[bind(&fPushOp, "OP_AND")]);
exclusive_or_expression = and_expression
>> *(('^' >> and_expression)[bind(&fPushOp, "OP_XOR")]);
inclusive_or_expression = exclusive_or_expression
>> *(('|' >> exclusive_or_expression)[bind(&fPushOp, "OP_OR")]);
single_expression = inclusive_or_expression;
series_expression = inclusive_or_expression
>> *((',' >> inclusive_or_expression)[bind(&fPushOp, "OP_SERIES")]);
logical_and_expression = series_expression
>> *(("&&" >> series_expression)[bind(&fPushOp, "OP_LOGICAL_AND")]);
logical_or_expression = logical_and_expression
>> *(("||" >> logical_and_expression)[bind(&fPushOp, "OP_LOGICAL_OR")]);
expression = logical_or_expression;
result = expression;
}
};
int main(){
Calculator<string::const_iterator> calc;
const string expr("!3 && 0,1");
string::const_iterator it = expr.begin();
parse(it, expr.end(), calc, qi::space);
cout << "Remaining: " << (string(it,expr.end())) << endl;
return 0;
}
預期的輸出如下:
PushInt: 3
PushOp: OP_NEGATE
PushInt: 0
PushInt: 1
PushOp: OP_SERIES
PushOp: OP_LOGICAL_AND
Remaining:
expr
為!3 && 0,1
時的當前輸出似乎表明&& 0,1
沒有被消耗:
PushInt: 3
PushOp: OP_NEGATE
Remaining: && 0,1
如果expr
為!3&&0,1
,那么它可以正常工作。 在調用qi::parse
時使用qi::space
跳線時,我看不出這兩個字符串的區別。 誰能指出我的問題?
您的規則不會聲明船長:
qi::rule<Iterator>
因此,它們隱式為lexeme
。 有關與船長有關的lexeme[]
的背景信息,請參見Boost Spirit船長問題
正確應用船長
您需要在語法和規則定義中聲明船長
template<class Iterator, typename Skipper = qi::space_type> struct Calculator : public qi::grammar<Iterator, Skipper> { qi::rule<Iterator, Skipper> expression, logical_or_expression, logical_and_expression, negate_expression, series_expression, single_expression, inclusive_or_expression, exclusive_or_expression, and_expression, equality_expression, relational_expression, shift_expression, additive_expression, multiplicative_expression, term, complement_factor, factor, result; qi::rule<Iterator> number, integer, variable, variable_combo, word;
傳遞船長類型的實例時需要使用phrase_parse
phrase_parse(it, expr.end(), calc, qi::space);
進一步說明:
phoenix.hpp
因為如果您遺漏了一些細微的位,您將被莫名其妙的bug所咬。當然,如果您知道哪些位,可以通過選擇性地包含子頭來減少編譯時間) 除非絕對必要,否則我強烈建議不要using namespace
。 在這種情況下,您很容易在bind
的多個品牌之一之間產生混淆。 而且,不,僅說using boost::phoenix::ref
是不夠的,因為
using boost::phoenix::ref; std::string s; bind(foo, ref(s))();
由於ADL而最終使用std::ref
而不是boost::phoenix::ref
#include <iostream>
#include <string>
#include <boost/spirit/include/qi.hpp>
#include <boost/spirit/include/phoenix.hpp>
namespace qi = boost::spirit::qi;
namespace phx = boost::phoenix;
void fPushOp(const std::string& op){
std::cout << "PushOp: " << op << std::endl;
}
void fPushInt(std::string& my_str){
std::cout << "PushInt: " << my_str << std::endl;
}
template<class Iterator, typename Skipper = qi::space_type>
struct Calculator : public qi::grammar<Iterator, Skipper> {
qi::rule<Iterator, Skipper>
expression, logical_or_expression, logical_and_expression,
negate_expression, series_expression, single_expression,
inclusive_or_expression, exclusive_or_expression, and_expression,
equality_expression, relational_expression, shift_expression,
additive_expression, multiplicative_expression, term,
complement_factor, factor, result;
qi::rule<Iterator>
number, integer, variable, variable_combo, word;
Calculator() : Calculator::base_type(result)
{
number =
qi::lexeme[
qi::as_string[
("0x" >> +qi::char_("0-9a-fA-F"))
| ("0b" >> +qi::char_("0-1"))
| ("0" >> +qi::char_("0-7"))
| +qi::char_("0-9")
] [phx::bind(&fPushInt, qi::_1)]
]
;
complement_factor = number
| ('~' >> number)[phx::bind(&fPushOp, "OP_COMPLEMENT")]
| ('!' >> number)[phx::bind(&fPushOp, "OP_NEGATE")];
;
term = complement_factor
>> *( (".." >> complement_factor)[phx::bind(&fPushOp, "OP_LEGER")]
| ('\\' >> complement_factor)[phx::bind(&fPushOp, "OP_MASK")]
);
multiplicative_expression = term
>> *( ('/' >> term)[phx::bind(&fPushOp, "OP_DIV")]
| ('%' >> term)[phx::bind(&fPushOp, "OP_MOD")]
| ('*' >> term)[phx::bind(&fPushOp, "OP_MUL")]
);
additive_expression = multiplicative_expression
>> *( ('+' >> multiplicative_expression)[phx::bind(&fPushOp, "OP_ADD")]
| ('-' >> multiplicative_expression)[phx::bind(&fPushOp, "OP_SUB")]
);
shift_expression = additive_expression
>> *( (">>" >> additive_expression)[phx::bind(&fPushOp, "OP_SRL")]
| ("<<" >> additive_expression)[phx::bind(&fPushOp, "OP_SLL")]
);
relational_expression = shift_expression
>> *( ('<' >> shift_expression)[phx::bind(&fPushOp, "OP_LT")]
| ('>' >> shift_expression)[phx::bind(&fPushOp, "OP_GT")]
| ("<=" >> shift_expression)[phx::bind(&fPushOp, "OP_LET")]
| (">=" >> shift_expression)[phx::bind(&fPushOp, "OP_GET")]
);
equality_expression = relational_expression
>> *( ("==" >> relational_expression)[phx::bind(&fPushOp, "OP_EQ")]
| ("!=" >> relational_expression)[phx::bind(&fPushOp, "OP_NEQ")]
);
and_expression = equality_expression
>> *(('&' >> equality_expression)[phx::bind(&fPushOp, "OP_AND")]);
exclusive_or_expression = and_expression
>> *(('^' >> and_expression)[phx::bind(&fPushOp, "OP_XOR")]);
inclusive_or_expression = exclusive_or_expression
>> *(('|' >> exclusive_or_expression)[phx::bind(&fPushOp, "OP_OR")]);
single_expression = inclusive_or_expression;
series_expression = inclusive_or_expression
>> *((',' >> inclusive_or_expression)[phx::bind(&fPushOp, "OP_SERIES")]);
logical_and_expression = series_expression
>> *(("&&" >> series_expression)[phx::bind(&fPushOp, "OP_LOGICAL_AND")]);
logical_or_expression = logical_and_expression
>> *(("||" >> logical_and_expression)[phx::bind(&fPushOp, "OP_LOGICAL_OR")]);
expression = logical_or_expression;
result = expression;
}
};
int main(){
Calculator<std::string::const_iterator> calc;
const std::string expr("!3 && 0,1");
std::string::const_iterator it = expr.begin();
phrase_parse(it, expr.end(), calc, qi::space);
std::cout << "Remaining: " << std::string(it,expr.end()) << std::endl;
return 0;
}
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