Keyword List Operators in Boost

Question

I am trying to parse an object where the order of the attributes doesn't matter.

For example, parsing an employee

employee {surname = "doe", firstname = "john", age = 30}

should be the same as

employee {age = 30, firstname = "john", surname = "doe"}

Ideally, my rule should be something like (not against the lack of a formal definition)

unordered_rule %= lit("employee") >> "{" 
             >> kwd("surname")["=" > quoted_string] 
            / kwd("age")["=" > int_] 
            / kwd("firstname")["=" > quoted_string] 
            / kwd("age")["=" > int] >> "}"; 

But first, how do I include separator commas in a parsing rule? And for my C ++ structure struct employee { std::string firstname; ... int age; }, is there an order of attributes or how to increase the value, which keyword matches that attribute, even after the structure has been converted to a merge vector?

It really doesn't work for me even after reading the documentation for the keyword list operators.

Answer 1

Fusion . , , , , .

( , - ... :)).

, . (qi::space | ',') qi::lexeme[] (. ).

lookahead,

unordered_rule %= lit("employee") >> "{" 
        >> (kwd("surname")  >> (&lit('}') | ',')) [ "=" > quoted_string ]
        / kwd("age")       >> (&lit('}') | ',')) [ "=" > int_ ]
        / kwd("firstname") >> (&lit('}') | ',')) [ "=" > quoted_string ]
        / kwd("age")       >> (&lit('}') | ',')) [ "=" > int ]
        >> "}";

( ).