Currently it's only legal to use struct member initializer when declaring a variable: struct Foo { int a; int b; } void main() { Foo foo = { a: 3, b: 4 }; } It would be a big improvement if something as the following was allowed: Foo{ a: 3, b: 4 } Then it would be possible to use the member initializer syntax in all places a regular struct initializer is supported. For example, together with "auto" and when calling functions: auto foo = Foo{ a: 3, b: 4 }; bar(Foo{ a: 3, b: 4 }); An alternative syntax could be to use parentheses instead: auto foo = Foo(a: 3, b: 4);
My use case: Vulkan uses structs to pass large amounts of parameters around. My current code looks like this: VkImageCreateInfo imgInfo = { imageType: VkImageType.VK_IMAGE_TYPE_2D, format: VkFormat.VK_FORMAT_R8G8B8A8_UNORM, // TODO: only allocate alpha if needed extent: image.size, mipLevels: image.mipLevels, arrayLayers: image.layers, samples: VkSampleCountFlagBits.VK_SAMPLE_COUNT_1_BIT, tiling: VkImageTiling.VK_IMAGE_TILING_LINEAR, //VK_IMAGE_TILING_OPTIMAL, usage: VkImageUsageFlagBits.VK_IMAGE_USAGE_TRANSFER_SRC_BIT | VkImageUsageFlagBits.VK_IMAGE_USAGE_SAMPLED_BIT, sharingMode: VkSharingMode.VK_SHARING_MODE_EXCLUSIVE, initialLayout: VkImageLayout.VK_IMAGE_LAYOUT_PREINITIALIZED, }; enforceVK(vkCreateImage(device, &imgInfo, null, &image.img)); It'd be really nice if it were possible to specify the struct inline with the creation call: auto img = createImage(device, VkImageCreateInfo { imageType: VkImageType.VK_IMAGE_TYPE_2D, // ... initialLayout: VkImageLayout.VK_IMAGE_LAYOUT_PREINITIALIZED, }); It'd also be very helpful for returning info structs from lamdas: auto queueCreateInfo = priorities .enumerate .filter!(x => x[1].length > 0) .map!((x) { VkDeviceQueueCreateInfo info = { queueFamilyIndex: x[0], queueCount: cast(uint) x[1].length, pQueuePriorities: x[1].ptr, }; return info; }) .array; You also basically have to use the the named field initialization syntax because each Vulkan info struct begins with a `sType` field and a `pNext` field, which at the moment should be a struct-specific constant and null that you don't really want to specify each time you create the struct.
My 2c: this is more D-like, auto foo = cast(Foo){ a: 3, b: 4 };
(In reply to Lionello Lunesu from comment #2) > My 2c: this is more D-like, > > auto foo = cast(Foo){ a: 3, b: 4 }; I disagree, this looks weird.
I just revived a DIP that deals with this topic: https://github.com/dlang/DIPs/pull/71 Help to polish it is welcome ;-)
*** Issue 19237 has been marked as a duplicate of this issue. ***
Another use case is with mixin expressions: --- struct S { int i; } void main() { S s = mixin(`{1}`); } ---
*** Issue 20173 has been marked as a duplicate of this issue. ***
This has been implemented in https://github.com/dlang/dmd/pull/14776