The XOROR sequence

Question

Cellular Automata are truly fascinating. The ones that are usually talked about are the binary ones, i.e., the ones representable by a number. However, those, in my opinion, have been done to death. Ternary CAs are more interesting, but we have all of ASCII to consider! What fun could that be!

Instead of deciding a ruleset for each character, I will use a simple deciding rule which I will talk about soon. To decide the next generation, we look at the three "top" cells, much like a cellular automata. Observe an example:

QWERTY
X Y Z

The "top" of Y is WER, being the cells above-and-right, above, and above-and left. Y will be the result of the function I'm about to define, which is a function on three-char strings. The "top" of X is QW, or a space filling in the non-existent/missing cell.

Now, for the fun function! I call this sequence the XOROR sequence for a reason. Let A be the top-left cell charcode, B be the above cell charcode, and C be the top-right cell charcode. Then, the resulting cell is the character whose charcode is (A XOR B) OR C, that is, (A^B)|C. (If a resulting value is greater than 126, then it is set to (CHARCODE % 127) + 32. Nothing is done if a value is less than 32.) Here is an example of the seed Hello, World!:

S: Hello, World!
0: mmmo/c_ z}~)e
   m = ( )^(H)|(e) = (32^72)|101 = 104|101 = 109 (m)
    m = (H)^(e)|(l) = (72^101)|108 = 45|108 = 109 (m)
    etc.
1: mmo/c_<   +wl
2: mo/c_<c< + |;
3: o/c_<c  ?+  g
4: oc_<c c??4+gg
5: 0_<c c  4+ o 
6: _<c ccc4??ooo
7:  c ccc4 ?o o 
8: ccccc4w? pooo
9: cccc4w h   o 
A: ccc4wc hh ooo
B: cc4wc4kh ooo 
C: c4wc4  #ooo o
D: wwc4w4#ooo oo
E: wc4wwc oo oo 
F: w4wwc4oo oo o
G: wwwc4   oo oo
H: wwc4w4 oo oo 
I: w4wwc4oooo oo
J: wwwc4  oo oo 
K: wwc4w4oo oo o
L: wc4wwo  oo oo
M: w4wwo8ooo oo 
N: wwwo8  o oo o
O: wwo8w8oooo oo

And we can proceed on for a while hereafter. This modification of the string is called the XOROR sequence.

Objective You are to write a program or function that does one of the following tasks:

1. Given a string s and a number n >= 0, output the nth string on the XOROR sequence with seed s, with n = 0 being the first transformation of the string.
2. Given a string s, output (for programs) or generate (for functions/generators) an infinite stream of the XOROR sequence with seed s. You may choose to stop if the sequence repeats, but this is not necessary.

s will always only consist of printable ASCII characters, from space to tilde plus tabs (no newlines.)

This is a code-golf, so the shortest program in bytes wins.

Answer 1

Mathematica, 133 bytes

FromCharacterCode@Nest[BlockMap[If[#>126,#~Mod~127+32,#]&[BitXor[#,#2]~BitOr~#3]&@@#&,ArrayPad[#,1,32],3,1]&,ToCharacterCode@#,#2+1]&

It would be nice to make a CellularAutomaton[] solution work, but I kept coming up short. Anyone?

Edit: some pretty pictures (click to enlarge)

plotCA[str_, n_] := ArrayPlot[NestList[foo[str],n], ColorFunction -> "Rainbow"]

plotCA["Hello, World!", 60]:

plotCA[bXORnotb, 100]:

plotCA[raven, 100]:

Answer 2

Java, 193 185 bytes

Because Java.

-8 bytes by switching to looping rather than recursing to make it an anonymous function

Returns the n'th iteration of XOROR on s.

(s,n)->{String o=s;for(;n-->=0;){o="";for(int i=0;i<s.length();i++){char c=(char)((i>1?s.charAt(i-1):' ')^s.charAt(i)|(i<s.length()-1?s.charAt(i+1):' '));o+=c>126?' ':c;}s=o;}return o;}

Readable version:

static BiFunction<String, Integer, String> f = (s,n)->{
    String o=s;
    for(;n-->=0;) {
        o = "";
        for (int i=0;i<s.length();i++) {
            char c=(char)((i>1?s.charAt(i-1):' ')^s.charAt(i)|(i<s.length()-1?s.charAt(i+1):' '));
            o+=c>126?' ':c;
        }
        s=o;
    }
    return o;
};

public static void main(String[]a) {
    System.out.println(f.apply("Hello, World",1));
}

Pretty much a literal implementation of the spec, with a recursive loop to apply the operation n times. Some bytes were saved, however, with my observation that the CHARCODE>126 clause will only ever happen with CHARCODE==127, which results in saving SPACE instead of DEL.

I ran my code over a few arbitrarily chosen strings and found this wonderful cycle:

oook$ok$ok$ok$
ook$ok$ok$ok$o
oo$ok$ok$ok$ok
oook$ok$ok$ok$

Answer 3

MATL, 33 31 bytes

Q:"32XKhKwh3YCPo2$1Z}Z~Z|127KYX

This works in release 13.1.0 of the language/compiler, which predates the challenge.

The first input is the number, the second is the string.

Try it online!

Q           % take input (number) implicitly and add 1
:"          % repeat that many times
  32XK      %   push 32 (space). Copy to clipboard K.
  h         %   concatenate. Takes input (string) implicitly the first time
  Kwh       %   push space, swap, concatenate
  3YC       %   overlapping blocks of length 3 as columns of 2D array
  P         %   flip upside-down 
  o         %   convert to numbers
  2$1Z}     %   separate the three rows and push them
  Z~        %   bitwise XOR (note the rows are in reverse order)
  Z|        %   bitwise OR
  127KYX    %   replace 127 by space using regexprep, which converts to char
            % end loop
            % implicitly display

Answer 4

CJam, 38 bytes

lri){2S*\*3ew{)\:^|_'~>{i127%' +}&}%}*

Test it here.

Explanation

l                e# Read string.
ri               e# Read n.
){               e# Run this block n+1 times...
  2S*\*          e#   Wrap in two spaces.
  3ew            e#   Get all (overlapping) substrings of length 3.
  {              e#   Map this block over all those substrings...
    )\           e#     Pull off the third character and put it below the other two.
    :^           e#     Take XOR of the other two.
    |            e#     OR with the third one.
    _'~>         e#     Duplicate and check if it's greater than '~'.
    {i127%' +}&  e#     If so, mod 127, add to space.
  }%
}*

Answer 5

Haskell, 123 bytes

import Data.Bits
f s=toEnum.a<$>zipWith3(((.|.).).xor)(32:s)s(tail s++[32])
a x|x>126=32|1<2=x
tail.iterate(f.map fromEnum)

This returns an infinite stream of the XOROR sequence. Usage example (print the first 5 elements of the seed "Hello, World!"):

*Main> mapM_ print $ take 5 $ (tail.iterate(f.map fromEnum)) "Hello, World!"
"mmmo/c_ z}~)e"
"mmo/c_<   +wl"
"mo/c_<c< + |;"
"o/c_<c  ?+  g"
"oc_<c c??4+gg"

How it works:

tail.iterate(f.map fromEnum)               -- repeat forever: convert to ASCII
                                           -- value and call f, discard the first
                                           -- element (the seed).

                                           -- one iteration is:
  zipWith3(   )(32:s) s (tail s++[32])     -- zip the elements from the three lists
                                           -- (space:s), s and tail of s ++ space,
                                           -- e.g. s = "Hello!":
                                           --   | Hello|
                                           --   |Hello!|
                                           --   |ello! |
                                           -- (shortest list cuts off)

         ((.|.).).xor                      -- the function to zip with is a
                                           -- point-free version of (x xor y) or z

toEnum.a<$>                                -- adjust every element >126 and convert
                                           -- back to characters

Answer 6

PHP, 186 bytes (with n) | 177 bytes (infinite)

It turned out that infinite printing is shorter...

// With n
function x($s,$n){while($n-->=0){for($i=0,$r='';$i<strlen($s);$i++){$b=ord($s[$i-1])or$b=32;$a=ord($s[$i+1])or$a=32;$t=($b^ord($s[$i]))|$a;$r.=chr($t>126?($t%127)+32:$t);}$s=$r;}echo$s;}

// Infinite
function i($s){while(true){for($i=0,$r='';$i<strlen($s);$i++){$b=ord($s[$i-1])or$b=32;$a=ord($s[$i+1])or$a=32;$t=($b^ord($s[$i]))|$a;$r.=chr($t>126?($t%127)+32:$t);}echo$s=$r;}}

Ungolfed with n:

function x($s, $n) { // $s - string to process; $n - which string to output
  while ($n-- >= 0) {
    for ($i = 0, $r = ''; $i < strlen($s); $i++) {
      $b = ord($s[$i - 1]) or $b = 32;
      $a = ord($s[$i + 1]) or $a = 32;
      $t = ($b ^ ord($s[$i])) | $a;
      $r .= chr($t > 126 ? ($t % 127) + 32 : $t);
    }
  $s = $r;
  }
  echo $s;
}

Ungolfed infinite:

function x($s) { // $s - string to process
  while (true) {
    for ($i = 0, $r = ''; $i < strlen($s); $i++) {
      $b = ord($s[$i - 1]) or $b = 32;
      $a = ord($s[$i + 1]) or $a = 32;
      $t = ($b ^ ord($s[$i])) | $a;
      $r .= chr($t > 126 ? ($t % 127) + 32 : $t);
    }
    echo $s = $r;
  }
}

Answer 7

Perl, 47 bytes

Includes +2 for -lp

Run with the input on STDIN, e.g. perl -lp xoror.pl <<< "Hello, World!" | head -26

xoror.pl:

/./s;$_=$_.chop^" $_"|"$' ";y/\x7f/ /;print;redo

This works as is, but replace the \x7f by the corresponding binary value to get the given score

Answer 8

C++

Nth-Sequence (212)

void x(char*s,int l,int n){for (;n-->0;) {char*t=new char[l-1](),w;for(int i=0;i<l-1;i++)t[i]=((w=(((i-1>= 0)?s[i-1]:32)^s[i])|((i+1<l-1)?s[i+1]:32))>126)?((w%127)+32):w;for(int i=0;i<l-1;i++)s[i]=t[i];delete[]t;}}

Un-Golfed

void x(char*s, int l, int n){
    for (;n-- > 0;) {
        char*t=new char[l-1](),w;
        for(int i = 0;i < l-1; i++)
            t[i] = ((w = (((i-1>= 0) ? s[i-1] : 32)^s[i]) | ((i+1 < l-1) ? s[i+1] : 32)) > 126) ? ((w % 127) + 32) : w;

        for(int i = 0; i < l-1; i++)
            s[i] = t[i];
        delete[]t;
    }
}

Nth-Sequence using pointer syntax instead of array syntax to make this all the more confusing: (231)

void x(char*s,int l,int n){for(int x=0;x++<n;) {char*t=new char[l-1](),w;for(int i=0;i<l-1; i++)*(t+i)=((w=(((i-1>= 0)?*(s+i-1):32)^*(s+i))|((i+1<l-1)?*(s+i+1):32))>126)?((w%127)+32):w;for(int i=0;i<l-1;i++)*(s+i)=*(t+i);delete[]t;}}

Un-Golfed

void x(char* s, int l, int n){
    for (;n-- > 0;) {
        char*t = new char[l-1](),w;
        for(int i = 0; i < l-1; i++)
            *(t+i) = ((w = (((i-1>= 0) ? *(s+i-1) : 32)^ *(s+i)) | ((i+1<l-1) ? *(s+i+1) : 32)) > 126) ? ((w%127)+32) : w;

        for(int i = 0;i < l-1; i++)
            s[i] = t[i];
        delete[]t;
    }
}

Debug Function (For Fun)

void d(char* seed, int len, int nth) {
    for (int n = 0; n++ < nth;) {
        char* tout = new char[len - 1]();
        for (int i = 0; i < len - 1; i++) {
            char x, y, z;
            x = ((--i >= 0) ? seed[i] : 32);
            y = seed[++i];
            z = ((++i < len - 1) ? seed[i] : 32);
            char w = (x ^ y) | z;
            tout[--i] = (w > 126) ? ((w % 127) + 32) : w;

            cout << "[" << x << " " << y << " " << z << "] " << w << endl;
        }

        for (int i = 0; i < len - 1; i++)
            seed[i] = tout[i];
        delete[] tout;
        cout << endl;
    }
}

Answer 9

JAVA 240/280 Bytes

The popular Java version at the time I wrote this claimed to be 185 bytes, but there are two significant fudge points. First, the measurement is presumably only for the function, not for the complete working source. Maybe not such a problem. Second, it uses BiFunction without either an import or a fully qualified name. Adding the required bits to run it as-is (then minimizing it, fairly) brought it to 348 bytes. Adding only the fully qualified name of the BiFunction class brings it to 248 bytes.

In contrast, I believe mine is 240 bytes when playing by the same rules (no class, no actual output, just the meat). The full runnable class is 280 bytes, and looks like this (unminified):

class z{
  public static void main(String[] s){
    int L=s[0].length();
    for(int G=Integer.valueOf(s[1]);G-->0;){
      s[1]="";
      for(int N=0;N<L;N++){
        char C=(char)((N>0?s[0].charAt(N-1):' ')^(s[0].charAt(N))|(N<L-1?s[0].charAt(N+1):' '));
        s[1]+=C>126?' ':C;
      }
      System.out.println(s[1]);
      s[0] =s[1];
    }
  }
}

Or, minified:

void m(String[] s){int L=s[0].length();for(int G=Integer.valueOf(s[1]);G-->0;){s[1]="";for(int N=0;N<L;N++){char C=(char)((N>0?s[0].charAt(N-1):' ')^(s[0].charAt(N))|(N<L-1?s[0].charAt(N+1):' '));s[1]+=C>126?' ':C;}s[0]=s[1];}return s[0];}

Answer 10

Swift: 273 Characters

Wow, Swift is worse than Java! (All those APIs with long names! :P)

func c(s:String,n:Int=0-1){var a=[UInt8](s.utf8);for i in 0...(n>=0 ?n:Int.max-1){var z="";for i in 0..<a.count{let A=i-1<0 ?32:a[i-1],B=a[i],C=i+1<a.count ?a[i+1]:32;var r=A^B|C;r=r<32 ?32:r>126 ?32:r;z+=String(UnicodeScalar(r))};if n<0||i==n{print(z)};a=[UInt8](z.utf8)}}

Ungolfed:

func cellularAutoma(s: String,n: Int = -1)
{
    var array = [UInt8](s.utf8)
    for i in 0...(n >= 0 ? n : Int.max - 1)
    {
        var iteration = ""
        for i in 0..<array.count
        {
            let A = i - 1 < 0 ? 32 : array[i - 1], B = array[i], C = i + 1 < array.count ? array[i + 1] : 32
            var r = A ^ B | C
            r = r < 32 ? 32 : r > 126 ? 32 : r
            iteration += String(UnicodeScalar(r))
        }
        if n < 0 || i == n
        {
            print(iteration)
        }
        array=[UInt8](iteration.utf8)
    }
}

Thanks to @CAD97 for mentioning that (A^B)|C can only be greater than 126 when it's 127.

I also realized that you don't need parenthesis around A^B|C because XORing is done before ORing, so that saved me a few bytes.

Answer 11

Vyxal, 23 bytes

(ðpǏ3lƛC÷∇꘍⋎:₇⇩>[32];C∑

Try it Online!

(                       # N times..
 ðpǏ                    # Enclose in spaces
    3l                  # Get overlapping substrings of length 3
      ƛ             ;   # Map...
       C÷               # Iterate out charcodes
         ∇꘍⋎            # XOROR
            :₇⇩>[  ]    # If greater than 126  
                 32     # Push 32
                     C∑ # Stringify and concatenate