or

If value is valid, it returns the value. If value is invalid, then elseValue is returned. If an elsePred is provided than that is called.

elsePred can return void as well, in which case frontOr also returns void.

auto or(T value)
auto
or
(
alias elsePred
T
)
(
auto ref T value
)
auto or(T value, U elseValue)

Parameters

value T: the value to check
elsePred: the perdicate to call if value is invalid

Return Value

Type: auto

Nullable!T: value.isNull ? elseValue : value

Optional!T: value.empty ? elseValue : value

Range!T: value.empty ? elseValue : value

Null-testable type: value is null ? elseValue : value

Examples

import optional.optional: some, no;

auto opt0 = no!int;
auto opt1 = some(1);

// Get or optional
assert(opt0.or(opt1) == opt1);
assert(opt1.or(opt0) == opt1);

// Lambdas
() @nogc {
    assert(opt0.or!(() => opt1) == opt1);
    assert(opt1.or!(() => opt0) == opt1);
}();

// Same with arrays/ranges

int[] arr0;
int[] arr1  = [1, 2];

// Get or optional
assert(arr0.or(arr1) == arr1);
assert(arr1.or(arr0) == arr1);

// Lambdas
() @nogc {
    assert(arr0.or!(() => arr1) == arr1);
    assert(arr1.or!(() => arr0) == arr1);
}();

or

Parameters

Return Value

Examples

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