Brainfucc

A small brainfuck interpreter for nodejs.

Introduction

Brainfuck is the most famous esoteric programming language, it's syntax consists of only 8 commands, represented by the following characters > < + - . , [ ].

Command	Description
>	Moves pointer to the right.
<	Moves pointer to the left.
+	Adds 1 to the memory cell under the pointer.
-	Subtracts 1 from the memory cell under the pointer.
.	Outputs the ASCII character represented by the value present in memory cell under the pointer. (Ex: 48 => 0)
,	Input a character and stores it's value in the memory cell under the pointer.
[	Jump past the matching ] if the cell under the pointer is 0.
>	Jump back to the matching [ if the cell under the pointer is nonzero.

Installation

$ npm install brainfucc

Basic usage

const brainfucc = require('brainfucc')
 
// Call brainfucc function.
brainfucc('+[-[<<[+[--->]-[<<<]]]>>>-]>-.---.>..>.<<<<-.<+.>>>>>.>.<<.<-.')

The above code will output hello world in the console.

Features

Memory Structure

• Brainfucc implements the memory as an array of 8-bit integers raging from 0 to 255.

• This memory wraps, so if you decrement a 0 it becomes a 255 and if you increment a 255 it becomes a 0.

• Memory by default has 30000 cells, initialized as 0.

Options

• memory - Controls the number of memory cells available to the code (Default = 30000).

// Makes available 5 memory cells. The code bellow outputs '0'.
brainfucc('++++++[> ++++++++ < -] > .', { memory: 5 })
 
// Initializes
//  v
// [0,0,0,0,0]

• delay - Controls the delay between the execution of each command, in milliseconds (Default = 0).

// Forces a 10 millisecond delay between each command execution.
brainfucc('+[-[<<[+[--->]-[<<<]]]>>>-]>-.---.>..>.<<<<-.<+.>>>>>.>.<<.<-.', { delay: 10 })

• debug - Display before each command, the current code position, loop stack and memory condition (Default = false). OBS: Memory condition is only displayed if the memory parameter is set to a value smaller than 51.

// Displays information about the current state of the machine at each step.
// The code bellow outputs '0'.
brainfucc('++++++[> ++++++++ < -] > .', { debug: true, memory: 5, delay: 200 })

Comments and whitespaces

• Brainfucc ignores every character except for the 8 brainfuck symbols > < + - . , [ ]. So comments can be made with any other characters.

// The code bellow will still output 'hello world'.
brainfucc('+[-[<<[+[--->]-[<<<]]]>>>-]>-.---.>..>.<<<<-.<+.>>>>>.>.<<.<-. returns a hello world!')
 
// Brainfucc also ignores spaces and newlines so
// the code bellow will still output 'hello world'.
brainfucc(`+[-[<<[+[--->]-
[<<<]]]>>>-]>-.---.>..>.<<<<-.
<+.>>>>>.>.<<.<-. 
returns a hello world!`)

Code validation and Runtime errors

• Brainfucc checks the code before running for mismatched loop brackets. If any dangling brackets are encountered it throws an exception.

// The code bellow will throw an exception.
brainfucc('[[]')

• If the code tries to access unavailable memory, Brainfucc throws an exception.

// The code bellow will throw an exception for 
// trying to access memory at the -1 position.
brainfucc('<')
 
 
// The code bellow will throw an exception for trying to 
// access memory greater than the number of cells alocated.
brainfucc('>>>', { memory: 3 })

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Contributing

If you find a bug or think that something is hard to understand feel free to open an issue or contact me on twitter @cvmcosta, pull requests are also welcome :).

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License