\documentclass[a4paper]{article}
\usepackage[scale=0.75]{geometry}
\usepackage{shortvrb}
\MakeShortVerb{\|}
\newcommand{\PkgVersion}{1.1}
\newcommand{\PkgDate}{2020/09/25}
\newcommand{\Pkg}[1]{\textsf{#1}}
\newcommand{\Meta}[1]{$\langle$\textit{#1}$\rangle$}
\newcommand{\Note}{\par\noindent \textbf{NB:}\quad}
\newcommand{\Means}{~:\quad}
\providecommand{\eTeX}{$\varepsilon$-{\TeX}}
%-----------------------------------------------------------
\begin{document}
\title{The \Pkg{bxcalcize} package}
\author{Takayuki YATO\quad (aka.~``ZR'')}
\date{v\PkgVersion \quad[\PkgDate]}
\maketitle

%===========================================================
\section{Notice}

Functionality of this package will be provided by the LaTeX
kernel of the version 2020/10/01.

%===========================================================
\section{Overview}

After loading \Pkg{calc}, most of the length specifications
in {\LaTeX} become aware of that package--- i.e.\ 
\Pkg{calc} expressions can be written in place of
simple lengths.
However some commands remain \Pkg{calc}-unaware; for example
one cannot use expressions in the argument of |\hspace|.
This package patches to the {\LaTeX} kernel and eliminates
remaining \Pkg{calc}-unawareness
(as far as I know).

\paragraph{Supported format} \LaTeX.
\paragraph{Supported engine} Any engine with {\eTeX} extensions.
\paragraph{Prerequisite packages} \Pkg{calc} package.

%===========================================================
\section{Package Loading}

Use |\usepackage| as usual, with no options.
\begin{quote}\small\begin{verbatim}
\usepackage{bxcalcize}
\end{verbatim}\end{quote}

%===========================================================
\section{Usage}

After loading the package, one can use \Pkg{calc} expressions
in the following places:
\begin{itemize}
\item the sole argument of |\hspace|(|*|), |\vspace|(|*|), 
and |\addvspace|;
\item the sole optional argument of |\\|.
\end{itemize}

%===========================================================
\end{document}
