Error

The <system_error> framework is used for error codes and exceptions.

Error codes and utilities are located in the <trial/protocol/json/error.hpp> header.

Error codes

Trial.Protocol defines its own json::error_category with associated error enumerator constants.

Normally, an error_code of the current error can be obtained via an error() member function.

std::string input = "illegal";
json::reader reader(input);

assert(reader.symbol() == json::symbol::error);
assert(reader.error() == json::invalid_value);

This conversion can also be done manually with json::to_errc() and json::make_error_code().

std::string input = "illegal";
json::reader reader(input);

assert(reader.symbol() == json::symbol::error);
assert(reader.code() == json::code::error_invalid_value);

enum json::errc ec = json::to_errc(reader.code());
assert(ec == json::invalid_value);

auto error = json::make_error_code(ec);
assert(error == json::invalid_value);

The following error codes exists.

Error Codes
`json::errc`	Description
`unexpected_token`	An unexpected token is encountered in the input.
`invalid_key`	An associative array key is not in a valid format.
`invalid_value`	The content is not in a valid format.
`incompatible_type`	Conversion between two incompatible types failed.
`unbalanced_end_array`	Encountered an end array token without a corresponding begin array token.
`unbalanced_end_object`	Encountered an end object token without a corresponding begin object token.
`expected_end_array`	Encountered an end array token outside an array.
`expected_end_object`	Encountered an end object token outside an associative array.

Exception

Conversion errors will result in json::error exceptions being thrown. json::error inherits from std::system_error which contains a std::error_code.