A New Turing Machine Model

Many should have been annoyed by the low-level-ness of the traditional Turing
Machine. Spu comes to the rescue.
Spu is a simple C++ class, the significance is that it can also be used as a
theoretical TM model, greatly simplifies deduction and statement based on TM
and also significantly provides a way of mechanical verification.
https://sourceforge.net/projects/cscall/

------------- Spu manpage
Wy.Sct.Spu(3wy)                                                 Wy.Sct.Spu(3wy)

NAME
       Spu - Class of general purpose Soft-CPU

SYNOPSIS
       Except POD types, C structures, all types are declared in namespace Wy.

       #include <CSCall/Sct.h>

       Spu  (Soft CPU) is a class that mimics the behavior of a general purpose
       CPU-based computing machine to provide semantics of  computing  language
       and for remote program communication.

       The  main  differences of Spu and general purpose CPU is that Spu has no
       ´register´ nor ´flag´, Spu has only a tape. Every object  on  the  tape,
       referred  to  as  tape  variable, is allocated via instruction Alloc and
       identified by a continuous index number.  Tape variable can contain  any
       C++ type, including Spu.

       The  instruction  of Spu is application definable. Except necessary few,
       about  >30  instructions  are  defined  for  convenience,  see   manpage
       Wy.Sct(3wy).

       Documentation following omits the scope name Wy::Sct for each occurrence
       of Spu for clearity.

PUBLIC MEMBERS
        class Reply
        typedef ssize_t IndexType
        Spu()
        ~Spu()

        InstrIdx next_instr
        Array<InstrIdx> istack
        Array<unsign char> tape
        PtrArray<InstrBase> program

        template<T> T& get_data(IndexType) const
        void set_instr_spu()
        Errno run(InstrIdx)
        Errno step()
        void add_instr(InstrBase*)
.....[cut]

From the theoretical side, Spu just added an insruction stack (istack) for
'call instruction', others are pretty much the same thing as the tradition TM.

For example, olcott's POOH has been discussed for a long time. One of the basic
problem is that POOH proof is invalid. The reason ('simulator') is a bit
abstract in traditional TM language. But, with Spu, it can be more clearer ---
The simulated program is actually a Spu instance in the tape, it has no way to
access the program (simulator) that simulates it. All things are concrete, not
easy to make words that only significant in the author's mind.