Expected

Union (sum) type of either an expected (most probable) value of type T or an unexpected value of type E (being an instance of type Unexpected!E).

E is typically an error code (for instance C/C++'s' errno int) or a subclass of Exception (which is the default).

struct Expected (

E = Exception

) if (

!isInstanceOf!(Unexpected, T) &&

!is(T == void)

) {

import core.lifetime : moveEmplace;;

template isAddress(T) via import nxt.container_traits : isAddress;;

this(T expectedValue);

this(Unexpected!E unexpectedValue);

void opAssign(T expectedValue);

void opAssign(E unexpectedValue);

bool hasExpectedValue();

import std.traits : CommonType;;

CommonType!(T, typeof(elseWorkFun())) valueOr();

import std.functional : unaryFun;;

Expected!(typeof(unaryFun!fun(T.init)), E) apply();

bool empty [@property getter];

inout(T) front [@property getter];

void popFront();

}

Constructors

this this(T expectedValue): Construct from expected value expectedValue.
this this(Unexpected!E unexpectedValue): Construct from unexpected value unexpectedValue.

Members

Functions

apply Expected!(typeof(unaryFun!fun(T.init)), E) apply(): If this is an expected value (of type T) apply fun on it and return result, otherwise return current unexpected value (of type E).
hasExpectedValue bool hasExpectedValue(): Is true iff this has a expectedValue of type T.
opAssign void opAssign(T expectedValue): Assign from expected value expectedValue.
opAssign void opAssign(E unexpectedValue): Assign from unexpected value unexpectedValue.
popFront void popFront(): Pop (clear) current value.
valueOr CommonType!(T, typeof(elseWorkFun())) valueOr(): Get current value if any or call function elseWorkFun with compatible return value.

Properties

empty bool empty [@property getter]: Check if empty.
front inout(T) front [@property getter]: Get current value.

Expected

Constructors

Members

Functions

Properties

See Also

Meta

Source