A class indicating that a parsed value can be automatically computed instead of specified.
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template<typename T, typename Label = AutoLabel::Auto>
class Options::Auto< T, Label >
A class indicating that a parsed value can be automatically computed instead of specified.
When an Auto <T>
is parsed from an input file, the value may be specified either as the AutoLabel
(defaults to "Auto") or as a value of type T
. When this class is passed to the constructor of the class taking it as an option, it can be implicitly converted to a std::optional <U>
, for any type U
implicitly creatable from a T
.
class ExampleClass {
public :
ExampleClass() = default ;
struct AutoArg {
static type suggested_value() { return {}; }
"Integer that can be automatically chosen" ;
};
struct OptionalArg {
};
struct AllArg {
};
"A class that can automatically choose an argument" ;
using options = tmpl::list<AutoArg, OptionalArg, AllArg>;
:
value (auto_arg ? *auto_arg : -12),
optional_value(opt_arg),
all_value(all_arg) {}
};
A class indicating that a parsed value can be automatically computed instead of specified.
Definition: Auto.hpp:43
constexpr T & value(T &t)
Returns t.value() if t is a std::optional otherwise returns t.
Definition: OptionalHelpers.hpp:32
const char *const String
The string used in option structs.
Definition: String.hpp:8
'All' label
Definition: Auto.hpp:27
const auto example1 = TestHelpers::test_creation<ExampleClass>(
"AutoArg: 7\n"
"OptionalArg: 10.\n"
"AllArg: [0, 1, 2]" );
CHECK(example1.value == 7);
CHECK(example1.optional_value == 10.);
const auto example2 = TestHelpers::test_creation<ExampleClass>(
"AutoArg: Auto\n"
"OptionalArg: None\n"
"AllArg: [0, 1, 2]" );
CHECK(example2.value == -12);
CHECK(example2.optional_value == std::nullopt);
const auto example3 = TestHelpers::test_creation<ExampleClass>(
"AutoArg: 7\n"
"OptionalArg: 10.\n"
"AllArg: All" );
CHECK(example3.value == 7);
CHECK(example3.optional_value == 10.);
CHECK(example3.all_value == std::nullopt);