Locals revisited

In hindsight my locals definition is not convincing,
because carnal knowledge about the behaviour of
the return stack is required.
"
   : local R> SWAP DUP >R @ >R >R CO R> R> ! ;

   VARIABLE A
   VARIABLE B

   : divide
      A local
      B local
      B ! A !  A @ B @ /
      . CR
   ;

   15 3 divide
"

Imagine a RiscV processor. Every low level word, doesn't use
the return stack, but uses a link register, so the above
probably doesn't work on a riscV.

To abstract of this you need an extra stack, for example
the "system stack" from Marcel Hendrix.
In the above it is necessary to temporarily store the return
information

   : local
       R>                          \ Return address
            SWAP DUP >R @ >R       \ Abuse return stack for extra storage
       >R                          \ Restore return address
       CO
            R> R> !                \ Further abuse
    ;


With the "system stack" it becomes :
"
   : local DUP >S @ >S CO S> S> ! ;

   VARIABLE A
   VARIABLE B

   : divide
      A local
      B local
      B ! A !  A @ B @ /
      . CR
   ;

   15 3 divide
"
Don't ask me these questions:

If you have an extra stack, why not use a locals stack?

R R> R@ 2R> etc. are a poor mans tool. Isn't it time to

replace them with >S S> S@ 2S> etc. and terminate all worries
these facilities interfere with other stuff?

(I get 30 registers in RISCV that can serve as a stack pointer.)

Groetjes Albert.
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