Custom command, counter and ref in Latex

Beginning of the Story

Before a paper is accepted somewhere, usually I will need to revise the paper based on the reviewers' comments. A document namely "replies_to_reviewer_comments.pdf" is necessary to answer the questions raised by the reviewers and state the changes of the revised paper.

One day I got a decision of my previously submitted paper. The result is "revise and resubmit". So sad. The comments are overwhelming. What I can do is to carry out more experiments, ammend the manuscript and write the "replies_to_reviewer_comments" to answer the questions. The structure and layout of the file is supposed to be like follows:

Reviewer #1
  Comment #1-1
    Blah blah
    Reply: 
    Blah blah
  Comment #1-2
    Blah blah
    Reply: 
    Blah blah
Reviewer #2
  Comment #2-1
    Blah blah
    Reply: 
    Blah blah

I want to add a 2.5mm space between Comment and Reply and make the text Reply: in bold font. Moreover, I don't like to repeat all this and manage all the numbers like #1-2 manually. Therefore I Googled a bit and found it was quite easy to do this with LaTeX.

New Command

Let put aside the numbers and just look at the format: adding space and bold font. I implemented these with three new commands: \reviewer, \comment and \reply.

Defining new command in Latex is easy. Just use the \newcomamnd or renewcommand command, as follows:

\newcommand{\reviewer}{%
\section*{Reviewer }}
\newcommand{\comment}{%
\subsection*{Comment }}
\newcommand{\reply}{%
\vspace{5 mm}%
{\bfseries Reply: }}

If you are interested in the details of \newcommand, please refer to the wiki page.

Managing Numbers: Counters

Now I have the three new commands and want to add the reviewer and comment number to them. Managing the numbers manually is a disaster if there are many comments. Fortunately, this can be easily solved by using counters.

First, I define two counters reviewerno and commentno and set them to 0:

\newcounter{reviewerno}
\setcounter{reviewerno}{0}
\newcounter{commentno}[reviewerno]
\setcounter{commentno}{0}

The counter commentno is defined as a sub-counter of reviewerno. This means that when reviewerno is changed, commentno will be reset to 0, which is exactly what I want.

Now I modify the command \reviewer and \comment to add counters to them:

\newcommand{\reviewer}{%
\stepcounter{reviewerno}%
\section*{Reviewer \#\arabic{reviewerno}}}
\newcommand{\comment}{%
\stepcounter{commentno}%
\subsection*{Comment \#\arabic{reviewerno}-\arabic{commentno}}}

The command \stepcounter{counter} increases counter by 1. Command \arabic{counter} outputs the value of counter in arabic numbers. More operations on counter can be found here.

Now I can write my replies like this:

\reviewer
  \comment
    Blah blah
    \reply 
    Blah blah

The nubmers will be automatically mantained and added by LaTeX.

Label and Ref

The new commands and counters work pretty good, but now I have a new requirement: two comments asked the same question. I want to answer it in the first comment and put a reference to the answer in the other one. Of course I can just hard code the comment number like "please refer to Comment #1-1 for details", but this is not flexible. What if the nubmer of the comment changes? I don't want to update all the references to it.

Now I need a reference to a custom counter. In LaTeX, we usually use the \label{label_name} command to define a label and \ref{label_name} to generate a reference to it. In fact, what \label{label_name} does is assigning the name label_name to the current value of \ref. Correspondingly, \ref{label_name} retrieves the value using label_name.

Here the command needed is \refstepcounter{counter}. It increases counter by 1 and sets the value of \ref to counter. We can simply replace the previous \stepcounter{count} with \refstepcounter{count}. Now we try to make a reference:

\reviewer
  \comment
    \label{com:novelty}
    Blah blah
    \reply 
    Blah blah
  \comment
    Blah blah
    \reply
    Please refere to our response to Comment \ref{com:novelty}

The output of the code is like this

Reviewer #1 
  Comment #1-1
  Blah blah
  Reply:
  Blah blah
  Comment #1-2
  Blah blah
  Reply:
  Please refere to our response to Comment 1

It works, but not perfectly. What we want to see is a reference to Comment #1-1. How can we set the \ref to two counters with formating in #reviewerno-commentno?

The trick is that everytime you define a counter, say counter, LaTeX will define a command \thecounter for it. counter is printed in LaTeX by using \thecounter. Hence we can redefine this command for commentno to let \ref print whatever we want. Now we define it with the following code:

\renewcommand{\thecommentno}{\#\arabic{reviewerno}-\arabic{commentno}}

and it works like a charm.

More details can be found at this link and the discussion here.

The Code and PDF File

The complete LaTeX source file and the generated PDF file can be found at my GitHub https://github.com/beyondwdq/Recipes/tree/master/latex/custom_ref.

The code is also listed as follows:

\documentclass[a4paper]{article}
\newcounter{reviewerno}
\setcounter{reviewerno}{0}
\newcounter{commentno}[reviewerno]
\setcounter{commentno}{0}
\renewcommand{\thereviewerno}{\#\arabic{reviewerno}}
\renewcommand{\thecommentno}{\#\arabic{reviewerno}-\arabic{commentno}}
\newcommand{\reviewer}{%
\refstepcounter{reviewerno}%
\section*{Reviewer \thereviewerno}}
\newcommand{\comment}{%
\refstepcounter{commentno}%
\subsection*{Comment \thecommentno}}
\newcommand{\reply}{%
\vspace{5 mm}%
{\bfseries Reply: }} 
\begin{document}
\title{Replies to Review-Comments}
\begin{center}
{\bfseries Summary of Changes}
\end{center}
\reviewer
\comment
\label{com:novelty}
The paper lacks novelty.
\reply 
The novelty of the paper is summarized as follows:
\begin{itemize}
    \item Novelty A
    \item Novelty B
\end{itemize}
\comment 
More simulations are need to fully evaluate the proposed method. The
contributions of the paper is not clear.
\reply 
We have carried out extensive simulations based on the reviewer's suggestion.
Please refer to Comment \ref{com:novelty} for the details of our contributions.
\reviewer
\comment
The paper is well-written and can be published with minor changes.
\reply 
We have revised the manuscript based on the reviewer's suggestion.
\end{document}