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const assert = @import("std").debug.assert;
test "optional type" {
const x: ?bool = true;
if (x) |y| {
if (y) {
// OK
} else {
unreachable;
}
} else {
unreachable;
}
const next_x: ?i32 = null;
const z = next_x orelse 1234;
assert(z == 1234);
const final_x: ?i32 = 13;
const num = final_x orelse unreachable;
assert(num == 13);
}
test "test maybe object and get a pointer to the inner value" {
var maybe_bool: ?bool = true;
if (maybe_bool) |*b| {
b.* = false;
}
assert(maybe_bool.? == false);
}
test "rhs maybe unwrap return" {
const x: ?bool = true;
const y = x orelse return;
}
test "maybe return" {
maybeReturnImpl();
comptime maybeReturnImpl();
}
fn maybeReturnImpl() void {
assert(foo(1235).?);
if (foo(null) != null) unreachable;
assert(!foo(1234).?);
}
fn foo(x: ?i32) ?bool {
const value = x orelse return null;
return value > 1234;
}
test "if var maybe pointer" {
assert(shouldBeAPlus1(Particle{
.a = 14,
.b = 1,
.c = 1,
.d = 1,
}) == 15);
}
fn shouldBeAPlus1(p: *const Particle) u64 {
var maybe_particle: ?Particle = p.*;
if (maybe_particle) |*particle| {
particle.a += 1;
}
if (maybe_particle) |particle| {
return particle.a;
}
return 0;
}
const Particle = struct {
a: u64,
b: u64,
c: u64,
d: u64,
};
test "null literal outside function" {
const is_null = here_is_a_null_literal.context == null;
assert(is_null);
const is_non_null = here_is_a_null_literal.context != null;
assert(!is_non_null);
}
const SillyStruct = struct {
context: ?i32,
};
const here_is_a_null_literal = SillyStruct{ .context = null };
test "test null runtime" {
testTestNullRuntime(null);
}
fn testTestNullRuntime(x: ?i32) void {
assert(x == null);
assert(!(x != null));
}
test "optional void" {
optionalVoidImpl();
comptime optionalVoidImpl();
}
fn optionalVoidImpl() void {
assert(bar(null) == null);
assert(bar({}) != null);
}
fn bar(x: ?void) ?void {
if (x) |_| {
return {};
} else {
return null;
}
}
const StructWithOptional = struct {
field: ?i32,
};
var struct_with_optional: StructWithOptional = undefined;
test "unwrap optional which is field of global var" {
struct_with_optional.field = null;
if (struct_with_optional.field) |payload| {
unreachable;
}
struct_with_optional.field = 1234;
if (struct_with_optional.field) |payload| {
assert(payload == 1234);
} else {
unreachable;
}
}
test "null with default unwrap" {
const x: i32 = null orelse 1;
assert(x == 1);
}
test "optional types" {
comptime {
const opt_type_struct = StructWithOptionalType { .t=u8, };
assert(opt_type_struct.t != null and opt_type_struct.t.? == u8);
}
}
const StructWithOptionalType = struct {
t: ?type,
};
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