wgslmsl

type Binding struct {
	Group, BindingIndex int
	Name                string // the WGSL variable name, for diagnostics
	MetalIndex          int
	// ElemBytes is the resource's element byte size (4 for f32/i32/u32, 8
	// for vec2<f32>, 16 for vec4<f32>, …) — the host needs it to compute
	// SizeMetalIndex's own element-count value from the bound GPUBuffer's
	// real byte length.
	ElemBytes int
}

type Options struct {
	// EntryPoint selects which @compute entry point to translate when the
	// module declares more than one. Empty selects the module's only
	// compute entry point (an error if there is more than one or none).
	EntryPoint string
}

type Result struct {
	MSL string
	// EntryPointName is the MSL function name to pass to Library.Pipeline —
	// NOT always the WGSL entry point's own name (a WGSL entry point named
	// "main" collides with Metal/C++'s own reserved main, so it is renamed;
	// see identMSL).
	EntryPointName string
	WorkgroupSize  [3]int
	Bindings       []Binding
	// SizeMetalIndex is the Metal buffer index of the synthesised
	// "_bufferSizes" struct every kernel with at least one runtime-sized
	// storage array binding takes — one uint32 per Bindings entry (same
	// order), each the bound buffer's real element COUNT (byte length /
	// ElemBytes). This is what every array index this package emits is
	// clamped against (see clampedIndex) — Metal performs no bounds
	// checking of its own, so this is a real security boundary, not a
	// correctness nicety: without it, a page's own WGSL could read or write
	// adjacent GPU memory outside its bound buffer via an out-of-range
	// index. -1 when no binding needs it (no array indexing was ever
	// bounds-checked because the kernel has no runtime-sized array
	// resource).
	SizeMetalIndex int
}