A Interpreter of Brainf**k

EaGitro
Collage Student
OVERVIEW

A interpreter of brainf**k with C lang

A Interpreter of Brainf**k

Brainf**k 言語の C言語によるインタプリンタです。

仕組みは意外と単純です。

デバッグモードという、コマンドの結果を1つづ表示するモードを搭載しています。

URL

https://github.com/EaGitro/brainfuck

What is this?

+++++++++++++[>+++++<-]>
+.
++++++++++++++++.
-----------------.
++++++++.
+++++.
--------.
+++++++++++++++.
------------------.
++++++++.

An interpreter of Brainf*ck with C lang

A short description of Brainf*ck

Wikipedia

Brainf*ck is one of the esoteric programming languages.

The processor of the Brainf*ck consists of the following elements:

  • a Brainf*ck program (in this application this is called "source")
  • a pointer pointing to a certain character in the program, which is generally called "instruction pointer"
  • an array of bytes (in this application this array is called "field array")
  • a pointer pointing to any element of the aforementioned array (an array of bytes) , which is generally called "data pointer" (in this application this is simply called "index")
  • input/output

And the Brainf*ck has following eight commands:

  • >
    • Increment the data pointer.
  • <
    • Decrement the data pointer.
  • +
    • Increment the byte which the the data pointer points to.
  • -
    • Decrement the byte which the the data pointer points to.
  • .
    • Output the byte which the the data pointer points to.
  • ,
    • Input the byte into element of array which the the data pointer points to.
  • [
    • If the byte which the data pointer points to is zero, the instruction pointer jumps to just after the matching ] command.
  • ]
    • The instruction pointer jumps to the matching [ command.

The system matching ] to [ in this application

Describing how the processor jumps from the ] to the matching [ in this application.

+++ [ >+++++<- ] >+
      ↑                    |
      +-----?----+


  1. This application's processor has a stack named "bracket stack".
  2. When the instruction pointer finds [, push the value of the instruction pointer (the position of the [ on the source) to the stack.
  3. When the instruction pointer finds ], the instruction pointer jumps to the position of the top value of the stack, and pop the value.

Compile

Please compile brainfuck.c simply.

How To Use

  1. Create the source code for Brainf*ck.

  2. Run this application.

  3. Enter the path to the Brainf*ck source code.

 file name > brainfuck_sumple_bf.txt

What is "debug mode"?

debug mode ? (Y/n) > Y

...

source 20th: <
input/output :
index: 0 / value: 11
---
bracket stack: 13
top 10 of field array: 11 15 0 0 0 0 0 0 0 0 0
action count: 41
---

The "debug mode" has following function:

  • Show the position now on the source code.

    • e.g. source    7th: +

  • Show the position and the value where the data pointer points.

    • e.g. index:    0 / value:    8

  • Show the status of the "bracket stack".

    • e.g. bracket stack:  27 42

  • Show the top 10 elements of the "field array".

    • e.g. top 10 of field array:  6 0 2 1 0 0 0 0 0 0 0

  • Shows how many the instruction pointer has moved.

    • e.g. action count: 41

Tips!

  • Only the eight commands are interpreted.
    • The other charactors are ignored.
  • And Comment Out is available.
    • Characters from # to \n are not readed in the first place.

Author

EaGitro (Twitter: @EaGitro)

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