# Cortex language 3A

Cortex language 3A is an esolang by User:PythonshellDebugwindow that follows the specifications of a Cortex language 3.

## Memory model

Cortex language 3A uses a tape of 16 arbitrary-size unsigned integers. The current cell is the cell pointed to by the cell pointer. The cell pointer wraps around the tape.

## Syntax

Same as brainfuck, e.g. each character is its own command that takes no arguments and returns no value. The one exception to this rule is the `;` command, whose result depends on the following character(s).

## Commands

Command Effect
`&` Increment the current cell
`'` If the current cell is zero, jump to the matching `:`
`*` Square the current cell
`~` Increment the cell pointer
`\$` Decrement the current cell (raises an error if cell == 0)
`:` If the current cell is nonzero, jump back to the matching `'`
`[` Output the Unicode character of the current cell
`]` Input an unsigned base-3 integer to the current cell
`;` Depends on the next instruction:
Command After Popular problem to run
`&` Print "Hello, World!" exactly like that
`'` Truth-machine
`*` ROT13 encode/decode user input
`~` Nth number in the Fibonacci sequence where N = base 10 user input
`\$` Interpret brainfuck where the program is inputted by the user
`:` Interpret Deadfish where the program is inputted by the user
`[` Bootstrap for program = user input
`]` FizzBuzz until 100
`;` Depends on the next instruction:
Command After Popular problem to run
`&` Cat program
`'` 99 bottles of beer
`*` Factorial of base 10 input number
`~` Digital root of base 10 input number
`\$` Infinite loop
`:` Run a looping counter from 0 to infinity
`[` Mandelbrot set
`]` Disan Count for base 10 input number
`;` Fibonacci sequence

All others are ignored. Sequences like `;X` and `;;X` are also ignored.

## Examples

```;&
```
```;'
```

Cat:

```;;&
```

ROT13 encoder/decoder for user input:

```;*
```

And so on.

## Turing-completeness

Through prime factorization of the tape, as well as unbounded looping using `'` and `:`, Cortex language 3A is Turing-complete.