Hito
Hito means 'one' in Japanese. Hito is a one-instruction Turing-complete esoteric programming language created by User:TheCanon2.
Hito was designed because of a critical flaw with the way its sister language Ichi handles input. In Ichi, both registers are overwritten whenever input is grabbed, which makes it impossible to store any permanent data.
Commands
Hito has two unbounded registers with addresses 0 and 1. The Hito command accepts only one operand, x.
Change register with address x modulo 2 by the numeric sign of x. If said register is -1, move 1 line forward. Else, goto line absolute of x divided by 2 rounded down.
However, there are three exceptions.
If x is 0 or 1, print the value of register x and unconditionally move 1 line forward.
If x is -1, accept a numeric input to be written to register 0 and unconditionally move 1 line forward.
The latter is the difference between Hito and Ichi; only register 0 is overwritten by input. And unlike Ichi, the -1 instruction isn't baked into every Hito program.
Line numbers start at 1 and increment by 1 for each line in the program. The program halts if the line number is greater than the length of the program.
Examples
All Ichi programs not reliant on input are fully compatible with Hito.
Hello, World!
5 7 9 11 13 15 17 19 -23 40 24 26 28 30 32 34 36 38 18 -42 0 47 49 51 53 -57 76 58 60 62 64 66 68 70 72 74 52 -78 -80 0 84 86 88 90 92 94 96 0 0 102 104 106 0 111 113 115 117 119 121 123 125 127 -131 -146 -132 -134 -136 -138 -140 -142 -144 -126 -148 -150 0 -154 -156 -158 -160 -162 -164 -166 -168 -170 -172 -174 -176 0 181 183 185 187 189 191 193 195 197 199 -203 214 204 206 208 210 212 198 0 219 221 223 225 227 229 231 -235 242 236 238 240 230 -244 0 248 250 252 0 -256 -258 -260 -262 -264 -266 0 -270 -272 -274 -276 -278 -280 -282 -284 0 289 291 293 295 297 299 301 303 305 -309 -324 -310 -312 -314 -316 -318 -320 -322 -304 -326 -328 0
Prints the ASCII values of the characters in 'Hello, World!' since Hito has no native character I/O.
Quine
0
This is the smallest in a set of infinitely many Hito quines with all-zero instructions.
Truth machine
-1 -12 8 0 18 14 0 -12
One-Time Cat
-1 0
XKCD Random Number
4 6 8 10 0
A+B problem
-1 7 -4 -11 -1 14 -13 -18 0
A-B problem
-1 7 -4 -11 -1 -15 -12 19 1
Disan Count
-1 1 -10 25 -14 25 17 19 -22 25 4
Simplified version in which the "is even!" text is not printed.
Print all natural numbers
0 2
Computational class
Hito is Turing-complete for it can simulate a two-register Minsky machine.
6 Increment register 0
-8 10 0 Decrement register 0 and jump to instruction 3 unless it is zero in which jump to instruction 4.
Implementations
The following Python script is an interpreter.
prgm = input('>Hito ')
prgm = list(prgm.split(" "))
for i in range(0, len(prgm)):
prgm[i] = int(prgm[i])
prgm.insert(0, -1)
# Initialises registers
cells = [0, 0]
# Executes program
inst = 1
def hito(x):
global prgm
global cells
global inst
if x == -1:
cells[0] = 0
init = input('>i ')
if len(init) > 0:
cells[0] = int(init)
inst += 1
elif x == 0 or x == 1:
print(cells[x], end=" ")
inst += 1
else:
cells[x % 2] += int(x / abs(x))
if cells[x % 2] == -1:
inst += 1
else:
inst = abs(x) // 2
while inst < len(prgm):
hito(prgm[inst])
This interpreter only supports interactive input. However Hito can also theoretically operate with input sequences, in which the -1 command becomes a Brainfuck comma.
Debugger variant:
…
while inst < len(prgm):
print("(Perform inst %d on data %s: \'%d\')" % (inst, cells, prgm[inst]))
hito(prgm[inst])