Brainfuck+

This is an interpreter for Brainfuck+ I made for fun. Brainfuck+ is very similar to the original Brainfuck, but with a few extra features.

TL;DR

• +10 is equivalent to ++++++++++, the same is true for <, > and -.
• Brainfuck+ has a register. ^ pushes data to register, v pulls data from register.
• # prints decimal, ! prints ASCII, ? reads input.
• Anything surrounded by two backticks (`) is a comment.

That's it.

Operation repetition

If any of the operators <, >, +, - is followed by a number n, that operator will execute n times.

For example: >>> can be written as >3, +12 is equivalent to ++++++++++++, you get the picture.

You can also use letters, their ASCII values will be used to repeat the operation. E.g: +a is equivalent to +97.

Note: "under the hood" >3 is faster than >>>, they both move the memory pointer three times to the right, but the first takes 1 cycle to execute while the other takes 3 cycles.

The register

Brainfuck+ has a "register" to which you can read and write a value. The operator ^ copies the data from the current memory cell into the register and the v operator copies the data from the register into the current memory cell.

Example:

Let's break down the following program: +5^>3v

(the snapshots between commands show the current state of the memory)

• Snapshot: strip: [0, 0, 0, 0, 0], reg: 0
• +5: increase current memory cell (which is 0) five times.
• Snapshot: strip: [5, 0, 0, 0, 0], reg 0
• ^: copy the value of the current cell (which is 5) into the register.
• Snapshot: strip: [5, 0, 0, 0, 0], reg 5
• >3: Move right three times
• Snapshot: strip: [5, 0, 0, 0, 0], reg 5
• v: Copy contents of register into current cell.
• Snapshot: strip: [5, 0, 0, 5, 0], reg 5

I/O

There are two write operators: !, which will print the current memory cell as an ASCII character, and #, which will print the raw value of the cell (as a decimal number).

The read operator is ?.

Comments

Since Brainfuck+ uses letters and numbers as operator repeaters, to add comments you need to surround them in two `. Example:

>5      `moves pointer to 5`
[-]     `reset cell value to 0`
+15     `set cell value to 15`
#       `print decimal value of cell`

Note: Backticks do not need to be closed, >10`hello 123 is valid Brainfuck+, it's the equivalent to >10.

A few important notes

Memory does not wrap! If the size of the memory strip is 5 cells and you try to access the cell at positions 0 or 6, the interpreter will panic.