Expanding Variables to Input as Arguments for Macro

Question

I have an issue when trying to use variables in a command (\ResearchModule). I read up to 8 lines from a text file and have them set to elements of an array (using code thanks to egreg!), with \ResearchModule checking to see if they are empty and properly format them. However, \ResearchModule doesn't like that I only provide the variable names and not actual values the arguments.

I've tried a few different iterations with \def, \edef, \expandafter, etc but can't get it to work properly.

Thanks for the help!

\documentclass[10pt]{article}

\usepackage{fancyhdr}
\usepackage[a4paper]{geometry}
\usepackage{tabularx}

\pagestyle{fancy}
\fancyhf{}
\fancyfoot{}
\renewcommand{\headrulewidth}{0pt}
\renewcommand{\footrulewidth}{0pt}

\addtolength{\oddsidemargin}{-2cm}
\addtolength{\evensidemargin}{-2cm}
\addtolength{\textwidth}{4cm}
\addtolength{\topmargin}{-2cm}
\addtolength{\textheight}{4cm}

\raggedbottom
\raggedright
\setlength{\tabcolsep}{0cm}

\newcommand{\dates}{3cm}
\newcommand{\tabitem}{~~\llap{\textbullet}~~}

\newcommand{\AddLine}[1]{
    \ifthenelse{\isempty{#1}}{}{\tabitem #1}
    \hangindent=0.2cm
    \par
}

\newcommand{\ResearchModule}[8]{
    \begin{tabularx}{\textwidth}[t]{p{\dates}X}
        #1 & \textbf{#2} \\
        & \textit{#3} \\
    \end{tabularx}
    \hspace*{3cm}
    \begin{minipage}{.835\textwidth}
    \begin{flushleft}
        \AddLine{#4}
        \AddLine{#5}
        \AddLine{#6}
        \AddLine{#7}
        \AddLine{#8}
    \end{flushleft}
    \end{minipage}%  
}

\ExplSyntaxOn
\ior_new:N \g_hringriin_file_stream

\NewDocumentCommand{\ReadFile}{mm}
    {\hringriin_read_file:nn{#1}{#2}
        \cs_new:Npn#1##1
            {\str_if_eq:nnTF{##1}{*}
                {\seq_count:c{g_hringriin_file_\cs_to_str:N#1_seq}}
                {\seq_item:cn{g_hringriin_file_\cs_to_str:N#1_seq}{##1}}
            }
    }

\cs_new_protected:Nn\hringriin_read_file:nn
    {\ior_open:Nn \g_hringriin_file_stream{#2}
        \seq_gclear_new:c{g_hringriin_file_\cs_to_str:N#1_seq}
        \ior_map_inline:Nn\g_hringriin_file_stream{
        \seq_gput_right:cx 
            {g_hringriin_file_\cs_to_str:N#1_seq}
            {\tl_trim_spaces:n{##1}}
        }
    \ior_close:N\g_hringriin_file_stream
    }

\ExplSyntaxOff

\begin{document}

\ReadFile{\myarray}{/file.txt}

\ResearchModule
    {\myarray{1}}
    {\myarray{2}}
    {\myarray{3}}
    {\myarray{4}}
    {\myarray{5}}
    {\myarray{6}}
    {\myarray{7}}
    {\myarray{8}}

\end{document}

Answer 1

I can't test this because you don't provide /file.txt, but the following should do. Your macro \myarray needs one full expansion to expand to the value, which is done by \ExpandArgs{e}.

I also replaced your \ifthenelse test with \IfBlankTF which is in the LaTeX kernel and the better test (though not completely equal, \IfBlankTF is also true for #1 containing spaces only).

\documentclass[10pt]{article}

\usepackage{fancyhdr}
\usepackage[a4paper]{geometry}
\usepackage{tabularx}

\pagestyle{fancy}
\fancyhf{}
\fancyfoot{}
\renewcommand{\headrulewidth}{0pt}
\renewcommand{\footrulewidth}{0pt}

\addtolength{\oddsidemargin}{-2cm}
\addtolength{\evensidemargin}{-2cm}
\addtolength{\textwidth}{4cm}
\addtolength{\topmargin}{-2cm}
\addtolength{\textheight}{4cm}

\raggedbottom
\raggedright
\setlength{\tabcolsep}{0cm}

\newcommand{\dates}{3cm}
\newcommand{\tabitem}{~~\llap{\textbullet}~~}

\newcommand{\AddLine}[1]{%
  \IfBlankTF{#1}{}{\tabitem #1}%
    \hangindent=0.2cm
    \par
}

\newcommand{\ResearchModule}[8]{
    \begin{tabularx}{\textwidth}[t]{p{\dates}X}
        #1 & \textbf{#2} \\
        & \textit{#3} \\
    \end{tabularx}
    \hspace*{3cm}
    \begin{minipage}{.835\textwidth}
    \begin{flushleft}
      \ExpandArgs{e}\AddLine{#4}
      \ExpandArgs{e}\AddLine{#5}
      \ExpandArgs{e}\AddLine{#6}
      \ExpandArgs{e}\AddLine{#7}
      \ExpandArgs{e}\AddLine{#8}
    \end{flushleft}
    \end{minipage}%  
}

\ExplSyntaxOn
\ior_new:N \g_hringriin_file_stream

\NewDocumentCommand{\ReadFile}{mm}
    {\hringriin_read_file:nn{#1}{#2}
        \cs_new:Npn#1##1
            {\str_if_eq:nnTF{##1}{*}
                {\seq_count:c{g_hringriin_file_\cs_to_str:N#1_seq}}
                {\seq_item:cn{g_hringriin_file_\cs_to_str:N#1_seq}{##1}}
            }
    }

\cs_new_protected:Nn\hringriin_read_file:nn
    {\ior_open:Nn \g_hringriin_file_stream{#2}
        \seq_gclear_new:c{g_hringriin_file_\cs_to_str:N#1_seq}
        \ior_map_inline:Nn\g_hringriin_file_stream{
        \seq_gput_right:cx 
            {g_hringriin_file_\cs_to_str:N#1_seq}
            {\tl_trim_spaces:n{##1}}
        }
    \ior_close:N\g_hringriin_file_stream
    }

\ExplSyntaxOff

\begin{document}

\ReadFile{\myarray}{/file.txt}

\ResearchModule
    {\myarray{1}}
    {\myarray{2}}
    {\myarray{3}}
    {\myarray{4}}
    {\myarray{5}}
    {\myarray{6}}
    {\myarray{7}}
    {\myarray{8}}

\end{document}