frontOr

If value is valid, it returns the internal value. This means .front for a range, .get for a Nullable!T, etc. 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 frontOr(T value)
auto
frontOr
(
alias elsePred
T
)
(
auto ref T value
)
auto frontOr(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.get or elseValue

Optional!T: value.front or elseValue

Range!T: value.front or elseValue

Examples

import optional.optional: some, no;

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

// Get or optional
assert(opt0.frontOr(789) == 789);
assert(opt1.frontOr(789) == 1);

// Lambdas
() @nogc {
    assert(opt0.frontOr!(() => 789) == 789);
    assert(opt1.frontOr!(() => 789) == 1);
}();

// Same with arrays/ranges

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

// Get frontOr optional
assert(arr0.frontOr(789) == 789);
assert(arr1.frontOr(789) == 1);

// Lambdas
() @nogc {
    assert(arr0.frontOr!(() => 789) == 789);
    assert(arr1.frontOr!(() => 789) == 1);
}();

frontOr

Parameters

Return Value

Examples

Meta

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