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(Un)computable
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(Un)computable is an esolang made by User:Marcus 2n2 and is uncomputable*.
Instructions
| Symbol | What they do |
|---|---|
X |
Pop a string. If that string halts, push H. Else, push L
|
H |
Print("Hello, World!") and halt immediately. |
L |
Perform an infinite loop, printing Ls.
|
N |
Negate. Pop a string. If it's H, push L. If it's L, push H. Else, no-op.
|
D |
Pop and place a string in front of the D.
|
(foo) |
Push foo.
|
I |
Push input. |
S |
Push source code |
P |
Pop and print string. |
/ |
Pop a string. If string ends with /, push string+/. Else, remove /.
|
Examples
Hello, World!
H
Cheating quine
SP
Infinite loop
L
Halting problem
SXND
XKCD Random Number
(4)P
Computable X
Yes, X is (sort of) computable!
X first runs the code as normal.
But since we can use the fact that L is the only one that runs an unconditional loop.
When the instruction pointer reaches an L, it returns L.
When it reaches an H or EOF, it returns H.