How to automatically generate code

Question

I am writing a paper that has lots of equations and it gets tedious having to retype my layout for each equation. Is there a way to automatically generate my next few lines of code after I type \begin{equation}

For example, currently I have this:

\documentclass [a4paper,12pt]{report}
\usepackage{amsmath}
\usepackage{array,tabularx,calc}
\newlength{\conditionwd}
\newenvironment{conditions}[1][where:]
  {%
   #1\tabularx{\textwidth-\widthof{#1}}[t]{
     >{$}l<{$} @{${}={}$} X@{}%>{\raggedright\arraybackslash}X@{}
   }%
  }
  {\endtabularx\par\addvspace{\belowdisplayskip}}


\begin{document}
A computational model was devloped by \citet{brown1977glue} which performs the necessary calculations for transformed section analysis. The program calculates the maximum moment (m) using equation \ref{eqn:PROLAM moment}

    \begin{equation}
        m_i = \frac{E_s}{E_j} \left( \frac{I_sF_i}{C_i} \right)
     \label{eqn:PROLAM moment}
\end{equation}
where:
\begin{itemize}[labelindent=20pt,leftmargin=*,widest=$M_x$,align=left,itemsep=0pt]
\item[$E_s$]        is the MOE for the standard material
\item[$E_j$]        MOE for the $i$-th lamination
\item[$F_i$]        Allowable stress of the $i$-th lamination
\item[$I_s$]        Is the moment of inertia of the transformed section
\item[$C_i$]        "Distance between the neutral axis of the transformed section and the extreme fiber of the $i$-th lamination"
\end{itemize}

\end{document}

Which produces a layout like this:

Is it possible for me type out something like \begin{equationlist} or \equationlist and have the following code automatically generated:

\begin{equation}

     \label{eqn:MY_LABEL}
\end{equation}
where:
\begin{itemize}[labelindent=20pt,leftmargin=*,widest=$M_x$,align=left,itemsep=0pt]
    \item[]
    .
    .
    .
\end{itemize}

I'm unsure if this has been asked anywhere else, i'm not exactly sure what to search for. I could just scroll up in my code and copy paste but generating this automatically would save me loads of time.

Edit: I am using Overleaf as my Tex editor

Answer 1

Depending what you want to get automatized, you could create a new command. I would suggest something like:

\newcommand\equationlist[2]{        % Params are the equation and the label
    \begin{equation}
        #1
        \label{eqn:#2}
    \end{equation}
    where:
    \begin{itemize}[labelindent=20pt,leftmargin=*,widest=$M_x$,align=left,itemsep=0pt]
        \item[]
    \end{itemize}
}

Then usage is simply:

\equationlist{m_i = \frac{E_s}{E_j} \left( \frac{I_sF_i}{C_i} \right)}{PROLAM moment}

As suggested by Steve, you may want to have a look at editor-specific snippets for more automation.

Now, following comments, here is a version that allows 'where' items to be given as parameters. It requires at least one parameter. Some code may be added to check whether one parameter has been given or not. I don't think this thing is useful as there is no economy in writing this. But, at least, it admits a variable number of parameters, thanks to this page.

Full code :

\documentclass [a4paper,12pt]{report}
\usepackage{amsmath}
\usepackage{enumitem}
\usepackage{array,tabularx,calc}

\newlength{\conditionwd}
\newenvironment{conditions}[1][where:]
{%
    #1\tabularx{\textwidth-\widthof{#1}}[t]{
        >{$}l<{$} @{${}={}$} X@{}%>{\raggedright\arraybackslash}X@{}
    }%
}
{\endtabularx\par\addvspace{\belowdisplayskip}}


\newcommand\equationlist[4]{        % Params are the equation, the label, the widest and the 'where' items
    \begin{equation}
        #1  
        \label{eqn:#2}
    \end{equation}
    \whereitems{#3}{#4}
}

\newcommand\whereitem[2]{\item[#1] #2}

\makeatletter
\newcommand{\checknextarg}{\@ifnextchar\bgroup{\gobblenextarg}{\end{itemize}}}
\newcommand{\gobblenextarg}[1]{ \item #1\@ifnextchar\bgroup{\gobblenextarg}{\end{itemize}}}
\makeatother

\newcommand{\whereitems}[2]{%   Params are widest and at least one parameter
    where:%
    \begin{itemize}[labelindent=20pt,leftmargin=*,widest=#1,align=left,itemsep=0pt]
        #2
        \checknextarg
    }

\begin{document}
    A computational model was devloped by [\ldots] which performs the necessary calculations for transformed section analysis. The program calculates the maximum moment (m) using equation \ref{eqn:PROLAM moment}

    \equationlist{
        m_i = \frac{E_s}{E_j} \left( \frac{I_sF_i}{C_i} \right)
    }{PROLAM moment}{$M_x$}{%
        \whereitem{$E_s$}{is the MOE for the standard material}
        \whereitem{$E_j$}{MOE for the $i$-th lamination}
        \whereitem{$F_i$}{Allowable stress of the $i$-th lamination}
        \whereitem{$I_s$}{Is the moment of inertia of the transformed section}
        \whereitem{$C_i$}{"Distance between the neutral axis of the transformed section and the extreme fiber of the $i$-th lamination"}
    }

\end{document}