Package brainfuck implements a brain fuck interpreter.

Basics

Interpreting occurs in three steps.

First, the Lexer breaks up a stream of code points (runes) into tokens.

These tokens represent the basic units of brain fuck syntax tree, such as whitespace, identifiers (like: > < + - . ,) and loops ( [ ] ).

Each scan returns a single token.

types:

	IllegalToken       
	LeftToken             // <
	RightToken            // >
	PlusToken             // +
	MinusToken            // -
	PrintToken            // .
	ReadToken             // ,
	LeftBracketToken      // [
	RightBracketToken     // ]
	WhitespaceToken      
	

• The second step is to feed these tokens into the parser which creates the abstract syntax tree (AST) based on the context of the tokens. below you will see a simple AST.

{
    {t:Token{Tok:MinusToken, Value:"-"}, c:1},
    {t:Token{Tok:LeftBracketToken, Value:"["}, c:7},
    {t:Token{Tok:MinusToken, Value:"-"}, c:2},
    {t:Token{Tok:LeftBracketToken, Value:"["}, c:5},
    {t:Token{Tok:PlusToken, Value:"+"}, c:1},
    {t:Token{Tok:RightBracketToken, Value:"]"}, c:3},
    {t:Token{Tok:MinusToken, Value:"-"}, c:2},
    {t:Token{Tok:RightBracketToken, Value:"]"}, c:1},
}

• The last step is to execute the produced instructions in step two by interpreter.

Abstract syntax tree, is very simple but not flat. The first level is simply contains identifiers (like: > < + - . ,). The second level contains the loops and it's internal blocks ( which can contains identifiers and loop block again), etc.

How to use

// create new io.Reader from inputs
code := strings.NewReader("----[---->+<]>++.+.+.+.")

// initialize the Parser with input
parser := brainfuck.NewParser(code)

// Standards interface to io
input := new(bytes.Buffer)
output := new(bytes.Buffer)

// initialize the machine
bfm := brainfuck.NewInterpreter(input, output, parser)

// Store the result in output interface 
_ = bfm.Run()

// print the result 
fmt.Println (output.String())

How to run tests

To run all tests in the root of the project run go test ./... command.