cli::ActionResult< T > Struct Template Reference

The result type produced and consumed at each step of an action pipeline. More...

#include <action.hh>

Public Types
enum class	State : std::uint8_t { ok , error , ignore }
using	value_type = T

Public Member Functions
constexpr	operator bool () const noexcept
	Returns true when the result represents success.
constexpr auto	have_value () const noexcept -> bool
	Returns true when the result represents success.
constexpr auto	has_value () const noexcept -> bool
	Returns true when the result represents success.
constexpr auto	has_error () const noexcept -> bool
	Returns true when the result represents failure.
constexpr auto	is_ignored () const noexcept -> bool
	Returns true when the result represents an ignored step.

Static Public Member Functions
template<class U>
static constexpr auto	ok (U &&v) -> ActionResult
	Creates a success result holding value.
static constexpr auto	fail (ParseError e) -> ActionResult
	Creates a failure result carrying error.
static constexpr auto	ignore () -> ActionResult
	Creates an ignore result.

Public Attributes
State	state {State::ok}
ParseError	error {}
T	value {}

Detailed Description

template<class T>
struct cli::ActionResult< T >

The result type produced and consumed at each step of an action pipeline.

An ActionResult<T> is a 3-state type: ok (carrying a value of type T), error (carrying a ParseError), or ignore (silent skip). The operator bool(), have_value(), has_value(), has_error(), and is_ignored() methods make it easy to check the state inline.

Factory methods:

• ActionResult<T>::ok(value) — create a success result.
• ActionResult<T>::fail(error) — create a failure result.
• ActionResult<T>::ignore() — create an ignore result.

Template Parameters

T	The value type held on success.

Definition at line 48 of file action.hh.

Member Typedef Documentation

value_type

template<class T>

using cli::ActionResult< T >::value_type = T

Definition at line 49 of file action.hh.

Member Enumeration Documentation

State

template<class T>

enum class cli::ActionResult::State : std::uint8_t

strong

Enumerator
ok
error
ignore

Definition at line 51 of file action.hh.

Member Function Documentation

fail()

template<class T>

constexpr auto cli::ActionResult< T >::fail ( ParseError e ) -> ActionResult

inlinestaticnodiscardconstexpr

Creates a failure result carrying error.

Parameters

e	The error to store.

Returns

A failed ActionResult<T>.

Definition at line 100 of file action.hh.

has_error()

template<class T>

auto cli::ActionResult< T >::has_error ( ) const -> bool

inlinenodiscardconstexprnoexcept

Returns true when the result represents failure.

Definition at line 73 of file action.hh.

has_value()

template<class T>

auto cli::ActionResult< T >::has_value ( ) const -> bool

inlinenodiscardconstexprnoexcept

Returns true when the result represents success.

Definition at line 68 of file action.hh.

have_value()

template<class T>

auto cli::ActionResult< T >::have_value ( ) const -> bool

inlinenodiscardconstexprnoexcept

Returns true when the result represents success.

Definition at line 63 of file action.hh.

ignore()

template<class T>

constexpr auto cli::ActionResult< T >::ignore ( ) -> ActionResult

inlinestaticnodiscardconstexpr

Creates an ignore result.

Returns

An ignored ActionResult<T>.

Definition at line 109 of file action.hh.

is_ignored()

template<class T>

auto cli::ActionResult< T >::is_ignored ( ) const -> bool

inlinenodiscardconstexprnoexcept

Returns true when the result represents an ignored step.

Definition at line 78 of file action.hh.

ok()

template<class T>

template<class U>

constexpr auto cli::ActionResult< T >::ok ( U && v ) -> ActionResult

inlinestaticnodiscardconstexpr

Creates a success result holding value.

Template Parameters

U	Type of the value (deduced).

Parameters

v	The value to store.

Returns

A successful ActionResult<T>.

Definition at line 90 of file action.hh.

operator bool()

template<class T>

cli::ActionResult< T >::operator bool ( ) const

inlineexplicitnodiscardconstexprnoexcept

Returns true when the result represents success.

Definition at line 58 of file action.hh.

Member Data Documentation

error

template<class T>

ParseError cli::ActionResult< T >::error {}

Definition at line 54 of file action.hh.

state

template<class T>

State cli::ActionResult< T >::state {State::ok}

Definition at line 53 of file action.hh.

value

template<class T>

T cli::ActionResult< T >::value {}

Definition at line 55 of file action.hh.

---

The documentation for this struct was generated from the following file:

• include/cli/action.hh