result.h File Reference

#include <expected>
#include <string>
#include <utility>
#include <rex/types.h>

Go to the source code of this file.

Classes
struct	rex::Error

Namespaces
namespace	rex

Macros
#define	REX_TRY_PASTE(a, b)
#define	REX_TRY_EXPAND_PASTE(a, b)
#define	REX_TRY(decl, expr)
#define	REX_TRY_VOID(expr)
#define	REX_ERROR_IF(cond, error)

Typedefs
template<typename T>
using	rex::Result = std::expected<T, Error>

Enumerations
enum class	rex::ErrorCategory : u8 {   kNoError , kIO , rex::kMemory , rex::kFormat ,   rex::kCrypto , kCompression , rex::kRuntime , kPlatform ,   kConfig , rex::kValidation , kNotFound , kNotImplemented ,   rex::kModule }

Functions
template<typename T>
Result< T >	rex::Ok (T &&value)
Result< void >	rex::Ok ()
template<typename T = void>
auto	rex::Err (Error error)
template<typename T = void>
auto	rex::Err (ErrorCategory category, std::string message, int code=0)

Detailed Description

Copyright

Copyright (c) 2026 Tom Clay tomc@.nosp@m.tcte.nosp@m.chstu.nosp@m.ff.c.nosp@m.om All rights reserved.

License

BSD 3-Clause License See LICENSE file in the project root for full license text.

Macro Definition Documentation

REX_ERROR_IF

#define REX_ERROR_IF	(		cond,
			error )

Value:

do {                               \
  if (cond) {                      \
    return std::unexpected(error); \
  }                                \
} while (0)

Returns an error from the enclosing function when a condition holds.

Parameters

error

The rex::Error to return when the condition is true.

REX_ERROR_IF(ptr == nullptr, rex::Error(rex::ErrorCategory::kValidation, "null"));

REX_TRY

#define REX_TRY	(		decl,
			expr )

Value:

auto REX_TRY_EXPAND_PASTE(_rex_try_, __LINE__) = (expr);                                \
if (!REX_TRY_EXPAND_PASTE(_rex_try_, __LINE__)) {                                       \
  return std::unexpected(std::move(REX_TRY_EXPAND_PASTE(_rex_try_, __LINE__)).error()); \
}                                                                                       \
decl = *std::move(REX_TRY_EXPAND_PASTE(_rex_try_, __LINE__))

Unwraps a rex::Result into a declaration, or returns its error from the enclosing function.

It is a statement, not an expression.

Parameters

decl	The declaration that receives the value.
expr	An expression of type rex::Result<T>.

REX_TRY(auto file, Open(path));

REX_TRY_EXPAND_PASTE

#define REX_TRY_EXPAND_PASTE	(		a,
			b )

Value:

REX_TRY_PASTE(a, b)

Pastes two tokens after expanding them, so __LINE__ becomes the line number.

auto REX_TRY_EXPAND_PASTE(_rex_try_, __LINE__) = Open(path);

REX_TRY_PASTE

#define REX_TRY_PASTE	(		a,
			b )

Value:

a##b

Pastes two tokens without expanding them first. Helper of REX_TRY_EXPAND_PASTE.

The example yields the token _rex_try_12.

REX_TRY_PASTE(_rex_try_, 12)

REX_TRY_VOID

#define REX_TRY_VOID

(

expr

)

Value:

do {                                                            \
  auto&& _rex_try_status = (expr);                              \
  if (!_rex_try_status) {                                       \
    return std::unexpected(std::move(_rex_try_status).error()); \
  }                                                             \
} while (0)

Returns the error of a rex::Result expression from the enclosing function.

Parameters

expr	An expression of type rex::Result<T>, usually rex::Result<void>.

REX_TRY_VOID(module->Init());