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Re: pforth return stack strangeness

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On Saturday, May 27, 2017 at 12:04:00 PM UTC-5, ad...@simple.gopher wrote:
> Maybe there are some pforth users here..
> 
> QUADRATIC example from page 112 in Starting Forth book:
> % pforth
>   / compute a * X^2 + b * X + c
>   : QUAD ( a b c X -- n) >R SWAP ROT I * + R> * + ;    ok
>   2 7 9 3 QUAD . ==> 30 ok
> 
> The answer should be 48.

The answer's also wrong under SwiftForth.

You can get the intended answer under both by accessing the top
of the return stack with R@ , rather than I :

  $ ./pforth_standalone 
  PForth V27-LE/64, built May 27 2017 12:18:53 (static)
  
  : quad >r swap rot r@ * + r> * + ; 2 7 9 3 quad . 48    ok
  Stack<10> 

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pforth return stack strangeness admin@simple.gopher - 2017-05-27 17:03 +0000
  Re: pforth return stack strangeness Julian Fondren <julian.fondren@gmail.com> - 2017-05-27 10:22 -0700
    Re: pforth return stack strangeness admin@simple.gopher - 2017-05-27 19:15 +0000
      Re: pforth return stack strangeness Julian Fondren <julian.fondren@gmail.com> - 2017-05-27 12:37 -0700
  Re: pforth return stack strangeness Roelf Toxopeus <rt4all@nothishetnet.nl> - 2017-05-27 21:10 +0200

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