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{} is a family of esolangs by User:PythonshellDebugwindow.
==Level 1==
{} Level 1 was the first attempt at an esolang in the {} family, although it was horribly ambiguous, too much so to parse (for human and machine alike). It uses an unbounded signed integer accumulator called acc.
===Commands===
Command 	Meaning
{} 	0
{{x}}	While acc > 0 do x (x can be any number of commands > 0)
{x} 	Set acc to x
{x{y} 	x + y
{{}} 	acc
A {} as x inside a {x} is indistinguishable from a {{}}.
===Computational class===
Due to its ambiguity, Level 1 is uncomputable.
==Level 2==
{} Level 2 was the second attempt at an esolang in the {} family. Like Level 1, it was too ambiguous to program in, and it uses an unbounded signed integer accumulator called acc.
===Commands===
Command 	Meaning
{} 	0
{x} 	acc = x (also evaluate to x)
{xy} 	If x then do y (y can be any number of commands > 0)
{{xy}}	While x ≠ 0 do y (y can be any number of commands > 0)
{{}} 	acc
{{x}} 	acc + x + 1
===Computational class===
Like Level 1, Level 2 is uncomputable due to its excessive ambiguity.
==Level 3==
{} Level 3 was the third attempt at an esolang in the {} family, and the first successful (i.e. non-ambiguous) one. It uses an unbounded signed integer accumulator called acc.
===Commands===
Command 	Meaning
{} 	0
{{}} 	++acc
{{x}}	acc = x
{xy} 	While acc ≠ x do y (y can be any number of commands > 0)
===Computational class===
Level 3 might be a push-down automaton, as its single accumulator can be incremented and reset (but not much else).
==Level 4==
{} Level 4 was the fourth attempt at an esolang in the {} family, and the second successful one. It uses an unbounded signed integer accumulator called acc.
===Commands===
Command 	Meaning
{} 	-1
{{}} 	acc
{{x}} 	acc = x
{{xy}}	x - y
{xy} 	While acc ≠ x do y (y can be any number of commands > 0)
===Computational class===
{} Level 4 is a push-down automata, as it has only one accumulator and no instructions to multiply/divide by a constant. (I could be wrong...)
==Level 5==
{} Level 5 was the fifth attempt at an esolang in the {} family, and the third successful one. It uses an array of unbounded signed integer registers called accs (the array is called accs). The array also has negative indices.
===Commands===
Command 	Meaning
{} 	-1
{{xy}} 	x - y
{{{xy}}}	accs[x] = y
{{{x}}} 	accs[x]
{{xyz}} 	While accs[x] != y do z (z can be any number of commands > 0)
===Computational class===
{} Level 5 is Turing complete. See the talk page for proof.
==Level 6==
{} Level 6 is the sixth esolang in the {} family, and the fourth successful one. It uses a bit called N and an array of integers called accs.
===Commands===
Command 	Meaning
{} 	-1
{{}} 	Nop
{{{x}}}	accs[N] += x
{{xy}} 	x - y
{xy} 	While accs[N] ≠ x do y (y can be any number of commands > 0)
After each command, N is swapped between 0 and 1.
===Computational class===
Level 6 has an unknown computational class, although by padding with nops, it could possibly be used to write programs.
==Level 7==
{} Level 7 is the seventh esolang in the {} family, and the fifth successful one. It uses a bit called N initialized to 0 and an array of two unbounded signed integers (the array is called accs) each initialized to 0.
===Commands===
Command 	Meaning
{} 	-1
{{}} 	accs[N]
{{x}} 	While accs[N] ≠ 0 do x (x can be any number of commands > 0 and ≠ 2)
{{xy}}	x - y
{xy} 	x + y
After each command, N is swapped between 0 and 1.
===Computational class===
Level 7 is Turing-complete, as it could simulate a two-register Minsky machine. (You can use {} on its own as a nop.)
==Level 8==
{} Level 8 is a brainfuck equivalent, making it the first esolang in the {} family known to be Turing-complete.
===Commands===
Level 8 	Brainfuck
{} 	+
{{}} 	-
{{}{}} 	>
{{}{}{}} 	<
{{}{}{}{}} 	,
{{}{}{}{}{}}	.
{{p}} 	[p]
Note that for the instruction {{p}} ([p]), p cannot be empty; if it is, the instruction will be treated as {{}} (-).
===Computational class===
Since Level 8 is a brainfuck equivalent, it is Turing-complete.
Category:Languages Category:2020 Category:Unimplemented Category:Uncomputable Category:Unknown computational class Category:Turing complete Category:Brainfuck equivalents Category:No IO Category:Usability unknown