How can I execute LaTeX code inside LaTeX code?

Question

I am writing a book. There are plenty of different examples of codes and on the other side of a page it displays the result of code. Sometimes I cannot compile my code and just put an image as a result of code, despite the fact that I compress all images as much as I can. It is a kind of wasting memory, so I would like to optimize the size of the book.

Is it possible somehow execute LaTeX code inside LaTeX code and see the final result? I expect something like this:

\documentclass[12pt]{article}
\usepackage{qqq}
\begin{document}
\begin{run_latex}
    \documentclass[12pt]{article}
    \usepackage{qqq}
    \begin{document}
    qqq
    \end{document}
\end{run_latex}


\end{document}

Here is my MWE:

\documentclass[12pt]{article}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage[english]{babel}
\usepackage{amsmath,amssymb}
\usepackage{array,tabularx}
\usepackage[table]{xcolor}
\usepackage{color}
\usepackage{hyperref}
\usepackage{listings}
\lstset{ basicstyle=\ttfamily, columns=fullflexible,
frame=single, breaklines=true, postbreak=\mbox{\textcolor{red}{$\hookrightarrow$}\space}}
\begin{document}
\subsection{ Aligning equations inbetween text}
\begin{tabular}{l | c}
\begin{minipage}[m]{0.4\textwidth}
RESULT OF EXECUTED CODE\textbf{}
\end{minipage}
& \begin{minipage}[m]{0.5\textwidth}
\renewcommand\textminus{\mbox{-}}
\begin{lstlisting}[basicstyle=\ttfamily\footnotesize]
\documentclass{article}
\usepackage{amsmath}
\begin{document}
\begin{alignat}{2}
\intertext{Photochemical:}
K_{UV} &: M[1]& &\ch{-> M^{}}[1]
\intertext{Catalyzed:}
K_I &: I& &\ch{->} 2R \
K_S &: R + M [1]& &\ch{-> RM^{}}[1]
\end{alignat}
\end{document}
\end{lstlisting}
\end{minipage}
\end{tabular}
\end{document}

Answer 1

One possibility: the tcolorbox package

For easier examples, it can directly display the output.

For full documents, including a documentclass, packages etc., this will internally produce a pdf of the output and include the pdf. As this is a vector graphic, it shouldn't increase the document size too much (needs to be compiled with shell-escape enabled).

% !TeX program = txs:///arara
% arara: pdflatex: {synctex: on, interaction: nonstopmode, shell: yes}
\documentclass[12pt]{article}
\usepackage[most]{tcolorbox}
\usepackage{mathtools}
\usepackage{chemmacros}
\tcbset{sidebyside}
\begin{document}
\begin{tcblisting}{}
\begin{alignat}{2}
\intertext{Photochemical:}
K_{UV} &: M[1]& &\ch{-> M^{}}[1]
\intertext{Catalyzed:}
K_I &: I& &\ch{->} 2R \
K_S &: R + M [1]& &\ch{-> RM^{}}[1]
\end{alignat}
\end{tcblisting}
\begin{tcblisting}{
listing and comment,
pdf comment,
freeze pdf,
compilable listing,
run pdflatex,
}
\documentclass[12pt]{article}
\begin{document}
qqq
\end{document}
\end{tcblisting}
\end{document}

Answer 2

Also as a variant

\documentclass{article}
\usepackage{showexpl}
\begin{document}
\begin{LTXexample}
$1+1=2$
\end{LTXexample}
\end{document}