Brainfuck

Brainfuck ist eine sehr einfache Programmiersprache, mit der man auch schöne Dinge tun kann. Zum Beispiel die TürmeVonHanoi:

[-][
****************************************
The Towers of Hanoi
Copyright (C) 2002 Roland Illig
1illig@informatik.uni-hamburg.de

This program is free software as
described in the GNU General Public
License;
****************************************

This is a _recursive_ version of the
Towers of Hanoi written in Brainfuck;
When you compare the source code the
ones written in other languages you
can easily see the relationship to
other imperative languages;

The stack consists of frames of the
length 8; The layout is as follows:

Byte Description
0 recursion flag
(the program stops if the flag is
zero)
1 the step which is currently
executed
4 means a call to
move(a c b sub(n 1))
3 means a call to
move(a b c 1)
2 means a call to
move(b a c sub(n 1))
1 prints the source and dest pile
2 flag to check whether the current
step has already been done or if
it still must be executed
3 the step which will be executed
in the next loop
4 the source pile
5 the helper pile
6 the destination pile
7 the number of disks to move
]

The first stack frame (0 0 0 0 0 0 0 0)
is used to abort the recursion
>>>>>>>>

These are the parameters for the program
(1 4 1 0 'a 'b 'c 5)
+>++++>+>>
>>>>++++++++[<++++++++++++>-]<
[<<<+>+>+>-]<<<+>++>+++>+++++>
<<<<<<<<

[> while (recurse)
[- if (step gt 0)
>[-]+< todo = 1
[- if (step gt 1)
[- if (step gt 2)
[- if (step gt 3)
>>+++<< next = 3
>-< todo = 0
>>>>>>[>+>+<<-]>[<+>-]> n dup
-
[[-] if (sub(n 1) gt 0)
<+>>>++++> push (1 0 0 4)

copy and push a
<<<<<<<<[>>>>>>>>+>+
<<<<<<<<<-]>>>>>>>>
>[<<<<<<<<<+>>>>>>>>>-]< >

copy and push c
<<<<<<<[>>>>>>>+>+
<<<<<<<<-]>>>>>>>
>[<<<<<<<<+>>>>>>>>-]< >

copy and push b
<<<<<<<<<[>>>>>>>>>+>+
<<<<<<<<<<-]>>>>>>>>>
>[<<<<<<<<<<+>>>>>>>>>>-]< >

copy n and push sub(n 1)
<<<<<<<<[>>>>>>>>+>+
<<<<<<<<<-]>>>>>>>>
>[<<<<<<<<<+>>>>>>>>>-]< -
>>
]
<<<<<<<<
]
>[-< if ((step gt 2) and todo)
>>++<< next = 2
>>>>>>>
+>>>+> push 1 0 0 1 a b c 1
<<<<<<<<[>>>>>>>>+>+
<<<<<<<<<-]>>>>>>>>
>[<<<<<<<<<+>>>>>>>>>-]< > a
<<<<<<<<[>>>>>>>>+>+
<<<<<<<<<-]>>>>>>>>
>[<<<<<<<<<+>>>>>>>>>-]< > b
<<<<<<<<[>>>>>>>>+>+
<<<<<<<<<-]>>>>>>>>
>[<<<<<<<<<+>>>>>>>>>-]< > c
+ >>
>]<
]
>[-< if ((step gt 1) and todo)
>>>>>>[>+>+<<-]>[<+>-]> n dup
-
[[-] if (n sub 1 gt 0)
<+>>>++++> push (1 0 0 4)

copy and push b
<<<<<<<[>>>>>>>+
<<<<<<<-]>>>>>>>
>[<<<<<<<<+>>>>>>>>-]< >

copy and push a
<<<<<<<<<[>>>>>>>>>+
<<<<<<<<<-]>>>>>>>>>
>[<<<<<<<<<<+>>>>>>>>>>-]< >

copy and push c
<<<<<<<<[>>>>>>>>+
<<<<<<<<-]>>>>>>>>
>[<<<<<<<<<+>>>>>>>>>-]< >

copy n and push sub(n 1)
<<<<<<<<[>>>>>>>>+>+
<<<<<<<<<-]>>>>>>>>
>[<<<<<<<<<+>>>>>>>>>-]< -
>>
]
<<<<<<<<
>]<
]
>[-< if ((step gt 0) and todo)
>>>>>>>
>++++[<++++++++>-]<
>>++++++++[<+++++++++>-]<++++
>>++++++++[<++++++++++++>-]<+++++
>>+++++++++[<++++++++++++>-]<+++
<<<
>.+++++++>.++.--.<<.
>>-.+++++.----.<<.
>>>.<---.+++.>+++.+.+.<.<<.
>.>--.+++++.---.++++.
-------.+++.<<.
>>>++.-------.-.<<<.
>+.>>+++++++.---.-----.<<<.
<<<<.>>>>.
>>----.>++++++++.<+++++.<<.
>.>>.---.-----.<<<.
<<.>>++++++++++++++.
>>>[-]<[-]<[-]<[-]
+++++++++++++.---.[-]
<<<<<<<
>]<
>>[<<+>>-]<< step = next
]
return with clear stack frame
<[-]>[-]>[-]>[-]>[-]>[-]>[-]>[-]<<<<<<
<<<<<<<<
>>[<<+>>-]<< step = next
<
]