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Re: Why I like Forth

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mhx@iae.nl writes:
>========================================
>Scilab 5.5.0 (Apr 11 2014, 12:13:09)
>
>-->abs(int8(-128))
> ans  =
>
> -128
>========================================
>marcel@me-tarzan ~
>$ echo "int main (void) { char a=-128; return printf("%d",abs(a)); }" > a.c; gcc a.c 2&>err; ./a
>128
>========================================
>iForth version 4.0.1782, generated 21:06:07, March 6, 2014.
>x86_64 binary, native floating-point, extended precision.
>Copyright 1996 - 2014 Marcel Hendrix.
>
>FORTH> -128 $FF AND abs . 128  ok
>========================================

And your point is?

ABS does not always produce a "positive" number even in Forth (and C):

-9223372036854775808 abs . -9223372036854775808  ok

However, one can consider "ABS ." to be a type error.  If you improve
this to

-9223372036854775808 abs u.

you get the right result (on a 64-bit system).  The difference in type
definitions between Forth and C is interesting, though:

|6.1.0690 ABS abs CORE	( n -- u )

vs.

|int abs(int j);
|Trying to take the absolute value of the most negative integer  is  not
|defined.


- anton
-- 
M. Anton Ertl  http://www.complang.tuwien.ac.at/anton/home.html
comp.lang.forth FAQs: http://www.complang.tuwien.ac.at/forth/faq/toc.html
     New standard: http://www.forth200x.org/forth200x.html
   EuroForth 2014: http://www.euroforth.org/ef14/

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Why I like Forth mhx@iae.nl - 2014-11-23 02:45 -0800
  Re: Why I like Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-11-23 13:29 +0000
    Re: Why I like Forth mhx@iae.nl - 2014-11-23 06:58 -0800
      Re: Why I like Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-11-23 15:28 +0000
        Re: Why I like Forth Julian Fondren <julian.fondren@gmail.com> - 2014-11-23 09:55 -0800
  Re: Why I like Forth "Rod Pemberton" <buzzoff@nonamewhichexists.cmm> - 2014-11-23 14:33 -0500
    Re: Why I like Forth Julian Fondren <julian.fondren@gmail.com> - 2014-11-23 12:35 -0800
      Re: Why I like Forth mhx@iae.nl - 2014-11-23 13:23 -0800

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