boost::urls::param
A query parameter
Synopsis
Declared in header <boost/url/param.hpp>
struct param;Description
Objects of this type represent a single key and value pair in a query string where a key is always present and may be empty, while the presence of a value is indicated by has_value equal to true. An empty value is distinct from no value.
Depending on where the object was obtained, the strings may or may not contain percent escapes.
For most usages, key comparisons are case-sensitive and duplicate keys in a query are possible. However, it is the authority that has final control over how the query is interpreted.
BNF
query-params = query-param *( "&" query-param )
query-param = key [ "=" value ]
key = *qpchar
value = *( qpchar / "=" )