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From: "Rod Pemberton" <dont_use_email@xnothavet.cqm>
Newsgroups: comp.lang.forth
Subject: Re: Brainfuck in ANS Forth
Date: Thu, 01 May 2014 16:08:22 -0400
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On Thu, 01 May 2014 11:31:38 -0400, Mark Wills <markwills1970@gmail.com>  
wrote:

> Just for fun...
>
>>  Increment the pointer.
> <  Decrement the pointer.
> +  Increment the byte at the pointer.
> -  Decrement the byte at the pointer.
> .  Output the byte at the pointer.
> ,  Input a byte and store it in the byte at the pointer.
> [  Jump forward past the matching ] if the byte at the pointer is zero.
> ]  Jump backward to the matching [ unless the byte at the pointer is  
> zero.
>
>
>
> create array
> 8000 chars allot

The array is usually 32KB.

> variable pointer
> array pointer !
>
> : reset ( -- )
>     \ zero bf memory and reset pointer
>     array 8000 0 fill
>     array pointer !  ;

0 fill.  Good.  Officially, BF doesn't need that.  But, I found that
some BF programs wont' work without it, and all seem to work with it.

> : peek ( -- )
>     pointer @ c@ ;
> : poke ( -- )
>     pointer @ c! ;
...

> : > ( -- )
>     \ increment the pointer
>     pointer @ 1+ pointer ! ;

How common is +! ?  It seems I picked it up from fig-Forth and one
critical word needs it.

> : < ( -- )
>     \ decrement the pointer
>     pointer @ 1- pointer ! ;
>
...

> : + ( -- )
>     \ increment the byte at the pointer
>     peek 1+ poke ;
> : - ( -- )
>     \ decrement the byte at the pointer
>     peek 1- poke ;

If you're using peek and poke, why not words for
  'pointer @' and 'pointer !' ...

> : . ( -- )
>     \ output the byte at the pointer
>     peek . ;

. or EMIT ?  Shouldn't it be EMIT ?  It's a value for a character.

> : , ( -- )
>     \ input a byte and store it in the byte at the pointer
>     pad 3 expect  pad 3 number  drop poke ;

Um, did ANS Forth remove KEY ?

> : [ \ ( -- )
>     \ jump forward past the matching ] if the byte at the pointer is zero
>     [compile] begin  compile peek  [compile] while ; immediate
> : ] ( -- )
>     \ jump backward to the matching [ unless the byte at the pointer is  
> zero
>     [compile] repeat ; immediate

...

> : hw
>     + + + + + + + + [ > + + + + [ > + + > + + + > + + + > + < < < < - ]  
> > +
>     > + > - > > + [ < ] < - ] > > . > - - - . + + + + + + + . . + + + .  
> > >
>     . < - . < . + + + . - - - - - - . - - - - - - - - . > > + . > + + . ;
>

Ha!  Each one has a space after them for Forth space parsing.  And, it's
a colon-def.  Awkward.

> Test:
>
> hw
> 72 101 108 108 111 32 87 111 114 108 100 33 10
>
> Note: BrainFuck can't emit characters, only numbers. So the Hello World!
> example above (taken from WikiPedia) outputs the ASCII *values* of Hello
> World! complete with a carriage return.
>
> http://en.wikipedia.org/wiki/Brainfuck

No.  You've misunderstood something.

It's supposed to emit ASCII text "Hello World!" with linefeed (ASCII LF  
0x0A).
The . in BF emits the ASCII character for the value.  If you look at the C
equivalent for . and , on the Wikipedia page, they use getchar() and  
putchar()
in C which fetches a char and emits a char, respectively.


Rod Pemberton