Creating nice form letters for nontechnical users

Question

I am trying to create a more complicated template but created this short example to document what I really want to do.

I want to create a form letter where the user will not see any complicated stuff which could be confusing. For this I want to hide all the datatool stuff

\documentclass{scrlttr2}
\usepackage{datatool}

\newcommand{\myDatabase}[1]{
    \DTLloaddb{test}{#1}%
}

%This is not working:
%\AtBeginDocument{
%   \DTLloaddb{test}{test.csv}%
%   \DTLforeach{test}{\name=Name, \age=Age}{%
%   \begin{letter}
%}
%
%\AtEndDocument{
%       \end{letter}}
%}

\myDatabase{test.csv}

\begin{document}
    \DTLforeach{test}{\name=Name, \age=Age}{% I want to remove this!
    \begin{letter}% I want to remove this!
        Dear Mr. \name
    \end{letter}}% I want to remove this!
\end{document}

My database test.csv looks just like this:

Name, Age
Alfred, 42
Brian, 23
Conrad, 66

My main problem is that splitting the \DTLForeach to appear at the beginning and conclude at the end of the document doesn't work. I tried already \bgroup and \egroup instead of using the bracket but this didn't change anything.

Answer 1

First of all, the letter environment requires an argument, namely the address. This is probably the reason why the word Dear or parts of it disappear.

Regarding how to hide the machinery for generating the letters, here is a solution with several elements:

• The definitions can be hidden by putting them into a style file or even a new document class (see below).

• To use the contents of an environment (its body) as argument of another command, use \NewEnviron from the package environ. Applied to your example:

  \documentclass{scrlttr2}
  \usepackage{datatool}
  \usepackage{environ}
  \NewEnviron{Letters}[1]{%
    \DTLloaddb{test}{#1}%
    \DTLforeach{test}{\name=Name, \age=Age}{%
      \begin{letter}{\name}
      \BODY
      \end{letter}%
    }%
  }
  \begin{document}
  \begin{Letters}{test.csv}
    \opening{Dear Mr.~\name}
  \end{Letters}
  \end{document}
  

• Finally, in order to hide \begin{documentclass} and \end{documentclass}, you have to use \aftergroup and a trick to make \BODY available after the Letters environment.

Here is the reduced input file:

\documentclass{myletters}
\begin{Letters}{test.csv}
  \opening{Dear Mr.~\name}
\end{Letters}

Put the following code into the file myletters.cls.

\ProvidesClass{myletters}[2018/07/20 My special letter class V0.42]
\LoadClass[a4paper,12pt]{scrlttr2}
% Define here any special class options
% \DeclareOption{...}{...}
% Pass all others to the underlying class
\DeclareOption*{\PassOptionsToClass{\CurrentOption}{scrlttr2}}
\ProcessOptions\relax

\RequirePackage{datatool}
\newcommand\MakeLetters{%
  \begin{document}
    \DTLforeach{test}{\name=Name, \age=Age}{% 
      \begin{letter}{\name}
      \ContentsOfLetter
      \end{letter}%
    }%
  \end{document}%
}

\RequirePackage{environ}
\NewEnviron{Letters}[1]{%
  \DTLloaddb{test}{#1}%
  \expandafter\gdef\expandafter\ContentsOfLetter\expandafter{\BODY}%
  \aftergroup\MakeLetters
}

Here is the output of both versions: