new_vmhook.nim

type
  TypeKind* = enum
    tkNone, tkFoo
  
  Foo* = object
    bar*: string

  Type* = object
    case kind*: TypeKind
    of tkNone: nil
    of tkFoo: fooVal*: Foo

proc getFoo(a: VmArgs; i: Natural): Foo =
  doAssert i < a.rc-1
  let s = cast[seq[Type]](a.slots)
  doAssert s[i+a.rb+1].kind == tkFoo
  result = s[i+a.rb+1].fooVal
  
# output when calling getFoo(a, 0) -
# Traceback (most recent call last)
# C:\Users\carte\projects\embeddedNimScript_old\test.nim(38) test
# C:\Users\carte\projects\embeddedNimScript_old\test.nim(25) main
# C:\Users\carte\projects\embeddedNimScript_old\embeddedNims\enims.nim(156) call
# C:\Users\carte\.nimble\pkgs\compiler-0.20.0\compiler\vm.nim(1946) execProc
# C:\Users\carte\.nimble\pkgs\compiler-0.20.0\compiler\vm.nim(1081) rawExecute
# C:\Users\carte\projects\embeddedNimScript_old\embeddedNims\apiImpl.nim(59) :anonymous
# C:\Users\carte\projects\embeddedNimScript_old\embeddedNims\apiImpl.nim(39) getFoo
# SIGSEGV: Illegal storage access. (Attempt to read from nil?)