generator: Handle <command> via vk-parse types and nom (#719)

For the upcoming `api` attribute in `vk.xml` commands also need to be
processed through `vk-parse` which has support for all the new
attributes, while `vkxml` is deprecated and completely untouched for
years.  This conversion unfortunately requires whipping up yet another
quick-and-dirty `nom` parser of a specific subset of C used in `vk.xml`
to describe parameter signatures.  This PR shows that conversion is
complete and provides no accidental semantic differences.

Also update `vk-parse` to `0.9` which contains a new `code` field on
`CommandParam` (`<param>` element) to be able to inspect the code
signature of individual parameters rather than parsing them out of (and
matching them back to `vk-parse`'s `params` array!) the `<command>`
/ `CommandDefinition` as a whole:
krolli/vk-parse#25 (comment)
krolli/vk-parse@615ffb6

ash/src/vk/extensions.rs

@@ -13331,7 +13331,7 @@ pub type PFN_vkGetPhysicalDeviceFragmentShadingRatesKHR = unsafe extern "system"
 pub type PFN_vkCmdSetFragmentShadingRateKHR = unsafe extern "system" fn(
     command_buffer: CommandBuffer,
     p_fragment_size: *const Extent2D,
-    combiner_ops: *const [FragmentShadingRateCombinerOpKHR; 2],
+    combiner_ops: *const [FragmentShadingRateCombinerOpKHR; 2usize],
 );
 #[derive(Clone)]
 pub struct KhrFragmentShadingRateFn {
@@ -13372,7 +13372,7 @@ impl KhrFragmentShadingRateFn {
                 unsafe extern "system" fn cmd_set_fragment_shading_rate_khr(
                     _command_buffer: CommandBuffer,
                     _p_fragment_size: *const Extent2D,
-                    _combiner_ops: *const [FragmentShadingRateCombinerOpKHR; 2],
+                    _combiner_ops: *const [FragmentShadingRateCombinerOpKHR; 2usize],
                 ) {
                     panic!(concat!(
                         "Unable to load ",
@@ -18058,7 +18058,7 @@ impl NvFragmentShadingRateEnumsFn {
 pub type PFN_vkCmdSetFragmentShadingRateEnumNV = unsafe extern "system" fn(
     command_buffer: CommandBuffer,
     shading_rate: FragmentShadingRateNV,
-    combiner_ops: *const [FragmentShadingRateCombinerOpKHR; 2],
+    combiner_ops: *const [FragmentShadingRateCombinerOpKHR; 2usize],
 );
 #[derive(Clone)]
 pub struct NvFragmentShadingRateEnumsFn {
@@ -18076,7 +18076,7 @@ impl NvFragmentShadingRateEnumsFn {
                 unsafe extern "system" fn cmd_set_fragment_shading_rate_enum_nv(
                     _command_buffer: CommandBuffer,
                     _shading_rate: FragmentShadingRateNV,
-                    _combiner_ops: *const [FragmentShadingRateCombinerOpKHR; 2],
+                    _combiner_ops: *const [FragmentShadingRateCombinerOpKHR; 2usize],
                 ) {
                     panic!(concat!(
                         "Unable to load ",

ash/src/vk/features.rs

@@ -999,7 +999,7 @@ pub type PFN_vkCmdSetDepthBias = unsafe extern "system" fn(
 );
 #[allow(non_camel_case_types)]
 pub type PFN_vkCmdSetBlendConstants =
-    unsafe extern "system" fn(command_buffer: CommandBuffer, blend_constants: *const [f32; 4]);
+    unsafe extern "system" fn(command_buffer: CommandBuffer, blend_constants: *const [f32; 4usize]);
 #[allow(non_camel_case_types)]
 pub type PFN_vkCmdSetDepthBounds = unsafe extern "system" fn(
     command_buffer: CommandBuffer,
@@ -2876,7 +2876,7 @@ impl DeviceFnV1_0 {
             cmd_set_blend_constants: unsafe {
                 unsafe extern "system" fn cmd_set_blend_constants(
                     _command_buffer: CommandBuffer,
-                    _blend_constants: *const [f32; 4],
+                    _blend_constants: *const [f32; 4usize],
                 ) {
                     panic!(concat!(
                         "Unable to load ",

generator/Cargo.toml

@@ -13,7 +13,7 @@ once_cell = "1.7"
 proc-macro2 = "1.0"
 quote = "1.0"
 regex = "1.4"
-vk-parse = { version = "0.7", features = ["vkxml-convert"] }
+vk-parse = { version = "0.9", features = ["vkxml-convert"] }
 vkxml = "0.3"
 
 [dependencies.syn]