Any special meaning in OCaml type definition -

When I see the definition of the build-in type of stack:

  (* Ocaml-2.04 / stdlib / stack.ml *) Type 'at = {mutable c:' a list} (* t means what's here *) to make the exception empty () = {c = []} clear s = Sc & lt; - [] push xs = sc & lt; - x :: sc let pop s = match with HD :: TL - & gt; S.c & lt; - tl; HD | [] - & gt; Leave the lifting length = list.Lambul s.c let's do this s = List.iter f s.c   
 What type of type is in "T" type? Thanks for explaining I thought it should only be the primitive type in type definition   
 
 After defining "text" itemprop = "text"> 
 in ocaml  c  coding is used to define The type of code explained by the module,  t  means the stack type. Since the file name is assumed with the missed ocaml module, stack.t for  t   
 Use it to view the following in the high-level ocaml (known as REPL) and see the output.  
  # emtpy_stack = stack.create () ;; Val empty_stack: '_a Stack.t = & lt; Abstr & gt;   
 Here is a variable of  empty_stack  type  Stack.t  an empty pile though.  
 In addition, it says that if you want to define a task that takes  stack  as a logic; Here is a way to define with type annotation,  
  # stack_func: (int) Stack.t = s;; Val stack_dummy: int stack.t - & gt; Int Stack.t = & lt; Funny & gt;