A brainfuck interpreter in TeX

brainfuck.sty

\ProvidesPackage{brainfuck}[2018/10/29 v1.0 A package to provide a Brainfuck interpreter interface]


\def \IgnoreSpaceInCode{%
    \endlinechar = 32\relax%
    \catcode 9   = 9\relax%
    \catcode 32  = 9\relax%
}
\def \AcknowledgeSpaceInCode{%
    \endlinechar = 13\relax%
    \catcode 9   = 10\relax%
    \catcode 32  = 10\relax%
}

\IgnoreSpaceInCode

\newcount\ptr
\ptr 0\relax
\def\decptr{\advance\ptr by -1\relax}
\def\incptr{\advance\ptr by +1\relax}

\def\activecounter{ptr\number\ptr}
\def\providecountr{
    \ifcsname\activecounter\endcsname
    \else
        \expandafter\newcount\csname \activecounter\endcsname
        \csname \activecounter\endcsname 0\relax
    \fi
}


\def\anynum#1{
    \providecountr
    \expandafter\advance\csname \activecounter\endcsname #1\relax
}
\def\deccount{
    \anynum{-1}
}
\def\inccount{
    \anynum{+1}
}

\def\leftbrace#1]{
    \providecountr
    \ifnum \activecharunsafe = 0 \else
        #1\leftbrace#1]
    \fi
}
\def\activecharunsafe{
    \expandafter\number\csname \activecounter\endcsname
}
\def\acitvecount{
    \providecountr
    \activecharunsafe
}
\def\activecountchar{
    \providecountr
    \ifnum \activecharunsafe = 32 \space\space\else
        \ifnum \activecharunsafe = 10 \par\else
            \expandafter\char\activecharunsafe
        \fi
    \fi
}

\def\activateBrainfuck
  {
    \catcode`< = \active\relax
    \catcode`> = \active\relax
    \catcode`- = \active\relax
    \catcode`+ = \active\relax
    \catcode`[ = \active\relax
    \catcode`. = \active\relax
    \catcode`, = \active\relax
  }

\begingroup
\activateBrainfuck
\newenvironment{brainfuck}
  {
    \begingroup
    
    % Assign stuff
    \let<\decptr
    \let>\incptr
    \let-\deccount
    \let+\inccount
    \let[\leftbrace
    %\let.\acitvecount
    \let.\activecountchar
    
    % Change the input reading
    \IgnoreSpaceInCode
    \activateBrainfuck
  }
  {
    \endgroup
  }
%Expose globally
\global\let\brainfuck\brainfuck
\global\let\endbrainfuck\endbrainfuck
\endgroup

\AcknowledgeSpaceInCode

main.tex

\documentclass{article}
\usepackage{brainfuck}

\title{Brainfuck}
\author{Kirens}
\date{October 2018}

\begin{document}

\maketitle

\section{Introduction}


\begin{brainfuck}
>>++++ ++++[<++++ ++++<++++>>-]<
++++++++.---.+++++++..+++.
<.>
++++++++.--------.+++.------.--------.
\end{brainfuck}

\end{document}