[colorforth] Eight instruction Turing-complete programming language
- Subject: [colorforth] Eight instruction Turing-complete programming language
- From: "John A. Peters" <japeters@xxxxxxxxxxx>
- Date: Fri, 27 Feb 2004 10:28:36 -0800
FWD from 4th-list@xxxxxxxxxxxxxxxxxx by JAP
Tired of programming languages whose goal it is to make your life easier?
Feel like stretching the 'ol grey matter a bit? Why not try coding in
Brainfuck!
"Did you say Brainfuck?"
Yup, that's what I said, Brainfuck.
Created by Urban Mueller, Brainfuck is an eight instruction Turing-complete
programming language. This means that it can be shown to be equivalent to a
Turing machine and therefore capable of performing any computation. (Click
here for a Google search on Turing machine.)
"Why would someone
Tired of programming languages whose goal it is to make your life easier?
Feel like stretching the 'ol grey matter a bit? Why not try coding in
Brainfuck!
"Did you say Brainfuck?"
Yup, that's what I said, Brainfuck.
Created by Urban Mueller, Brainfuck is an eight instruction Turing-complete
programming language. This means that it can be shown to be equivalent to a
Turing machine and therefore capable of performing any computation. (Click
here for a Google search on Turing machine.)
Etc more here -
http://cydathria.com/bf/brainfuck.html
----- Original Message -----
From: "Hans Bezemer" <thebeez@xxxxxxxxx>
To: <4th-list@xxxxxxxxxxxxxxxxxx>
Sent: Thursday, February 26, 2004 10:28 AM
Subject: [4th-list] Brainf*ck interpreter
> I stumbled upon a strange computer language with a bit of a controversial
> name and wondered whether I could make an interpreter in 4tH for it. My
old
> pal Benjamin Hoyt had already done it for another language, so I could not
> stay behind. I had a hack for about 15 minutes and it worked (although it
is
> still slow). Here you have the source. Enter the name of this language in
> google and you'll find some sites with programs. Please note, that it
doesn't
> run every single program as well and it is slow (it's an interpreter!!).
>
> Programs that it is known to run acceptably:
>
> -rw-r--r-- 1 habe users 5832 Feb 26 19:22 factor.bf
> -rw-r--r-- 1 habe users 352 Feb 25 22:45 fib.bf
> -rw-r--r-- 1 habe users 4983 Feb 25 23:48 hanoi.bf
> -rw-r--r-- 1 habe users 185 Feb 25 22:30 hello.bf
> -rw-r--r-- 1 habe users 4100 Feb 26 19:21 prime.bf
> -rw-r--r-- 1 habe users 895 Feb 25 22:41 ryanbeer.bf
> -rw-r--r-- 1 habe users 1649 Feb 25 22:57 triangle.bf
>
> --- CUT HERE ---
>
> \ 4tH BrainFuck interpreter - Copyright 2004 J.L. Bezemer
> \ You can redistribute this file and/or modify it under
> \ the terms of the GNU General Public License
>
> include lib/lookup.4th
> \ BF memory
> 30000 constant #BFMemory
> #BFMemory string BFmemory
> \ BF source
> 8192 constant #BFSource
> #BFSource string BFSource
>
> 10 constant EOL \ end of line character
> variable level \ level for jumps
> defer next \ jump program counter instruction
> \ get character from TIB
> : char> ( t p m -- t p m c)
> >r >r dup tib = \ save pointers, if start buffer
> if refill drop then \ then refill the buffer
> dup c@ dup 0= \ get character, if end of string
> if EOL + nip tib swap \ return LF and signal end of
buffer
> else swap char+ swap \ else increment pointer
> then r> r> rot \ restore pointers and rotate char
> ;
>
> : p@ over c@ ; \ fetch program instruction
> : m@ dup c@ ; \ fetch memory contents
> : m! over c! ; \ store memory contents
> : m++ char+ ; \ increment memory pointer
> : m-- char- ; \ decrement memory pointer
> : p++ swap char+ swap ; \ increment program pointer
> : p-- swap char- swap ; \ decrement program pointer
> : >m char> m! ; \ store input at memory pointer
> : m> m@ emit ; \ emit content at memory pointer
> : m@++ m@ 1+ m! ; \ increment contents at mem pointer
> : m@-- m@ 1- m! ; \ decrement contents at mem pointer
>
> : level-- = if -1 level +! then ; \ increment level if equal
> : level++ = if 1 level +! then ; \ decrement level if equal
> \ jump to location
> : jump ( p m c1 c2 xt -- p' m)
> is next ( p m c1 c2)
> >r rot swap ( m p c1)
> begin ( m p c1)
> p@ dup r@ level-- ( m p c1 p@)
> over level++ ( m p c1)
> level @ ( m p c1 n)
> while ( m p c1)
> next ( m p' c1)
> repeat ( m p' c1)
> r> drop drop swap ( p' m)
> ;
> \ BF jump instructions
> : <p [char] ] [char] [ ['] p-- jump p-- ;
> : ?p> m@ 0= if [char] [ [char] ] ['] p++ jump then ;
> \ BF operators table
> create BFop
> char > , ' m++ ,
> char < , ' m-- ,
> char + , ' m@++ ,
> char - , ' m@-- ,
> char . , ' m> ,
> char , , ' >m ,
> char [ , ' ?p> ,
> char ] , ' <p ,
> NULL ,
> \ open a file from argument n
> : (open) ( m n -- h)
> args over over >r >r rot open dup 0= ( h f)
> if ( h)
> stdout use \ force use of stdout
> ." Cannot open " \ write message
> r> r> type cr abort \ write filename
> else ( h)
> dup use r> r> drop drop \ use file, clear return stack
> then ( h)
> ;
> \ read BF source
> : ReadBF ( --)
> argn 2 < \ if no filename issued
> abort" Usage: bf sourcefile" \ issue error message
> input 1 (open) \ open the input file
> BFSource #BFSource \ setup source buffer
> over over erase accept \ read sourcefile
> #BFSource = abort" File too large" \ check size
> close \ close file
> ;
> \ initialize interpreter
> : InitBF ( -- a1 a2 a3)
> 0 level ! \ reset level
> BFMemory #BFMemory erase \ clear memory
> tib BFSource BFMemory \ setup parameters
> ;
> \ run interpreter
> : ExecBF ( a1 a2 a3 --)
> p@ \ get operator
> begin \ begin
> BFop 2 1 lookup \ find operator
> if execute else drop then \ if found execute else drop
> p++ p@ dup 0= \ increment program counter
> until \ until end-of-code marker
> drop drop drop drop \ drop pointers
> ;
>
> : BF ReadBF InitBF ExecBF ;
>
> BF
>
> --
> ================
> "First make it work, then improve it."
> Visit our website! http://come.to/hansoft
>
> *** Home of the 4tH compiler! ***
>
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