Result

Result of T with optional error E. Designed for error handling where an operation can either succeed or fail. - TODO: Add member toRange alias with opSlice - TODO: Add member visit()

@safe

struct Result (

E = void

) {

import core.lifetime : move, moveEmplace;;

this(T value);

this(E error);

~this();

typeof(this) opAssign(T value);

static if(hasError)

typeof(this) opAssign(E error);

inout(T) value [@property getter];

static if(hasError)

inout(E) error [@property getter];

inout(T) opUnary [@property getter];

T opEquals [@property setter];

typeof(this) opEquals [@property setter];

string toString [@property getter];

bool isValue [@property getter];

static if(hasError)

bool isError [@property getter];

bool opCast [@property getter];

static typeof(this) invalid [@property getter];

}

Constructors

this this(T value): Undocumented in source.
this this(E error): Undocumented in source.

Destructor

~this ~this(): Undocumented in source.

Members

Functions

opAssign typeof(this) opAssign(T value): Undocumented in source. Be warned that the author may not have intended to support it.
opAssign typeof(this) opAssign(E error): Undocumented in source. Be warned that the author may not have intended to support it.

Properties

error inout(E) error [@property getter]: Undocumented in source. Be warned that the author may not have intended to support it.
invalid typeof(this) invalid [@property getter]: Undocumented in source. Be warned that the author may not have intended to support it.
isError bool isError [@property getter]: Undocumented in source. Be warned that the author may not have intended to support it.
isValue bool isValue [@property getter]: Undocumented in source. Be warned that the author may not have intended to support it.
opCast bool opCast [@property getter]: Undocumented in source. Be warned that the author may not have intended to support it.
opEquals T opEquals [@property setter]: Undocumented in source. Be warned that the author may not have intended to support it.
opEquals T opEquals [@property setter]: Undocumented in source. Be warned that the author may not have intended to support it.
opEquals typeof(this) opEquals [@property setter]: Undocumented in source. Be warned that the author may not have intended to support it.
opUnary inout(T) opUnary [@property getter]: Undocumented in source. Be warned that the author may not have intended to support it.
toString string toString [@property getter]: Undocumented in source. Be warned that the author may not have intended to support it.
value inout(T) value [@property getter]: Undocumented in source. Be warned that the author may not have intended to support it.

Examples

to string conversion

alias T = int;
alias R = Result!T;
const R r1;
assert(r1.toString == "invalid");
const R r2 = 42;
assert(r2.toString == "42");
R r3 = r2;
r3 = 42;
assert(*r3 == 42);
assert(r3 == 42);
T v42 = 42;
assert(r3 == v42);

result of uncopyable type

alias T = Uncopyable;
alias R = Result!T;
const R r_ = R(T.init);
R r1;
assert(!r1);
assert(r1 != r_);
assert(!r1.isValue);
T t = T(42);
r1 = move(t);
assert(r1 != r_);
assert(*r1 == T(42));
R r2 = T(43);
assert(*r2 == T(43));
assert(r2.value == T(43));

result of pointer and error enum

alias V = ulong;
alias T = V*;
enum E { first, second }
alias R = Result!(T, E);
R r1;
assert(!r1);
assert(r1 == R.invalid);
assert(r1 != R(T.init));
assert(!r1.isValue);
assert(r1.isError);
assert(r1.error == E.init);
assert(r1.error == E.first);
T v = new V(42);
r1 = move(v);
assert(r1 != R(T.init));
assert(**r1 == V(42));

result of pointer and error enum toString

alias V = ulong;
alias T = V*;
enum E { first, second }
alias R = Result!(T, E);
R r1;
assert(r1.toString == "first");
r1 = T.init;
assert(r1.toString == "null");

result of pointer and error enum

alias V = ulong;
alias T = V*;
enum E { first, second }
alias R = Result!(T, E);
R r2 = new V(43);
assert(**r2 == V(43));
assert(*r2.value == V(43));

result of pointer and error enum

alias V = ulong;
alias T = V*;
enum E { first, second }
alias R = Result!(T, E);
R r2 = E.first;
assert(r2.error == E.first);
r2 = E.second;
assert(r2.error == E.second);

Result

Constructors

Destructor

Members

Functions

Properties

Examples

Meta

Source