Dead fish

Not to be confused with Deadfish.

The title of this article is not correct because of technical limitations. The correct title is actually ><x>.

><x> is a 2D esolang created by User:None1, it is a cross between Deadfish and ><>, but the i command in ><> is l in ><x>.

Commands

Commands in ><x>

Command	Meaning	Derives from
i	Increments the accumulator	Deadfish
d	Decrements the accumulator	Deadfish
s	Squares the accumulator	Deadfish
o	Outputs the accumulator as ASCII	><>
n	Outputs the accmulator as decimal	><>
l	Input a character and store its ASCII code in accumulator	><>
^	IP direction up	><>
v	IP direction down	><>
<	IP direction left	><>
>	IP direction right	><>
?	If accumulator is zero, skip next instruction	><>
;	Halts the program	><>
space	NOP	><>

A ><x> program terminates if and only if:

1. The IP is out of bound.
2. The IP hits ;.
3. The IP hits an invalid character, in this case, the program prints Nope. before terminating.

It uses only one wrapping accumulator that contains numbers from 0 to 255, and the IP is at the top left and its direction is initially right.

Examples

Hello World

iiisdsiiiiiiiioiiiiiiiiiiiiiiiiiiiiiiiiiiiiioiiiiiiiooiiiodddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddoddddddddddddodddddddddddddddddddddsddoddddddddoiiioddddddoddddddddodddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddo

Cat Program (never terminates)

>lov
^  <

Truth Machine

lddddddddddddddddddddddddddddddddddddddddddddddddn?v
                                                 >n<

A smaller version that takes advantage of the accumulator being bound to the range [0, 255]

ls?vn;
   >sss>n<

An even smaller version in Codegolf Stack Exchange

lssss>n?<

Quine

Nope.

Nope. interpreter

Nope.

or simply

a

Count backwards from 100 to 1

iiiiiiiiiis>nd?v
           ^   <

Count forwards from 1 to 100

dddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddd>iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiindddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddd?v
                                                                                                    ^                                                                                                                                                                                                           <

Interpreter

C++

#include<iostream>
#include<string>
#include<vector>
#include<algorithm>
#include<fstream>
std::vector<std::string> code;
int w,h,ipx,ipy,ipdx,ipdy=1;
unsigned char x;
signed main(int argc,char* argv[]){
	if(argc==1) return std::cout<<"Needs an input file",0;
	std::string s;
	std::fstream f(argv[1],std::ios::in);
	while(std::getline(f,s)){
		h++;
		w=std::max(w,(int)s.size());
		code.push_back(s);
	}
	f.close();
	for(auto i:code){
		while(i.size()<w) i+=" ";
	}
	while(ipx>=0&&ipx<h&&ipy>=0&&ipy<w){
		switch(code[ipx][ipy]){
			case 'i':{
				x++;
				break;
			}
			case 'd':{
				x--;
				break;
			}
			case 's':{
				x*=x;
				break;
			}
			case 'n':{
				std::cout<<x<<std::endl;
				break;
			}
			case 'o':{
				std::cout<<char(x&255);
				break;
			}
			case 'l':{
				x=std::cin.get();
				break;
			}
			case '^':{
				ipdx=-1;
				ipdy=0;
				break;
			}
			case 'v':{
				ipdx=1;
				ipdy=0;
				break;
			}
			case '<':{
				ipdx=0;
				ipdy=-1;
				break;
			}
			case '>':{
				ipdx=0;
				ipdy=1;
				break;
			}
			case '?':{
				if(x) break;
				ipx+=ipdx;
				ipy+=ipdy;
				break;
			}
			case ';':{
				return 0;
			}
			case ' ':{
				break;
			}
			default:{
				std::cout<<"Nope.";
				return 0;
			}
		}
                ipx+=ipdx;
                ipy+=ipdy;
	}
	return 0;
}