Add comment from removed argument.jl

res/wrap/README.md

@@ -5,3 +5,46 @@ This directory contains scripts to generate Julia wrappers for Metal and MetalPe
 Currently, only `enums` and `structs` are able to be generated.
 
 The scripts are meant to be run from this directory, and at the moment, [this Clang.jl branch](https://github.com/christiangnrd/Clang.jl/tree/objectiveC) must be used.
+
+####
+
+Comment from removed file on `MTLDataType`. Parsing the headers does not reveal these hidden values.
+
+```
+#=
+
+Possible (undocumented) values for this enum can be iterated using the MTLTypeInternal type:
+
+\`\`\`julia
+load_framework("Metal")
+
+@objcwrapper immutable=false MTLType <: NSObject
+
+@objcwrapper immutable=false MTLTypeInternal <: MTLType
+
+@objcproperties MTLTypeInternal begin
+    @autoproperty dataType::UInt64
+    @autoproperty description::id{NSString}
+end
+
+function MTLTypeInternal(dataType::Integer)
+    obj = MTLTypeInternal(@objc [MTLTypeInternal alloc]::id{MTLTypeInternal})
+    finalizer(dealloc, obj)
+    @objc [obj::id{MTLTypeInternal} initWithDataType:dataType::UInt64]::id{MTLTypeInternal}
+    return obj
+end
+
+dealloc(obj::MTLTypeInternal) = @objc [obj::id{MTLTypeInternal} dealloc]::Cvoid
+
+for i in 1:200
+    typ = MTLTypeInternal(i)
+    name = string(typ.description)
+    if name != "Unknown"
+        println("    $name = $i")
+    end
+end
+\`\`\`
+
+=#
+
+```