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Groups > comp.lang.forth > #41893

Re: `don't` instead of `?do`

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En/Je/On 2015-09-08, Julian Fondren <julian.fondren@gmail.com>
escribió/skribis/wrote:

> On Monday, September 7, 2015 at 3:20:46 PM UTC-5, Marcos Cruz wrote:

>>   : don't  ( n1 n2 -- | n1 n2 )
>>     2dup = if  2drop unnest unnest then  ;

> unnest ?
>
>  : don't ( n n -- )
>     2dup = if 2drop r>drop r>drop then ;

Right, `unnest` does `rdrop` (or `r>drop` in your case).

> A more common word is ?DO , which does nothing if its arguments are
> equal.

> then DON'T is just a less versatile clone of ?DO ,which can be used
> within a larger word

Of course, I know. `don't` is *a simple alternative I wrote while I
implement `?do`*, and only useful when the loop is in its own word, not
in larger words, as you point out.

I think my intention was not clear because, by mistake, the word `?do`
was missing from the first sentence of my message: "I still haven't
implemented `?do` in a Forth of mine."

Regards,

-- 
Marcos Cruz
http://programandala.net

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Thread

`don't` instead of `?do` Marcos Cruz <null_email_so_use_my_contact_page@programandala.net> - 2015-09-07 20:20 +0000
  Re: `don't` instead of `?do` Julian Fondren <julian.fondren@gmail.com> - 2015-09-08 11:32 -0700
    Re: `don't` instead of `?do` Coos Haak <chforth@hccnet.nl> - 2015-09-09 00:38 +0200
      Re: `don't` instead of `?do` Julian Fondren <julian.fondren@gmail.com> - 2015-09-08 15:52 -0700
        Re: `don't` instead of `?do` Coos Haak <chforth@hccnet.nl> - 2015-09-09 00:58 +0200
    Re: `don't` instead of `?do` Marcos Cruz <null_email_so_use_my_contact_page@programandala.net> - 2015-09-09 11:53 +0000
      Re: `don't` instead of `?do` Mark Wills <markwills1970@gmail.com> - 2015-09-09 08:48 -0700
        Re: `don't` instead of `?do` Bernd Paysan <bernd.paysan@gmx.de> - 2015-09-09 20:59 +0200
          Re: `don't` instead of `?do` hughaguilar96@gmail.com - 2015-09-10 21:26 -0700

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