Creating a table with for loop over a list

Question

I am currently trying to learn Latex with writing my CV with it. I am stuck at the point that I want to list my skills. I just want to have a simple function that takes a dynamic list of skills and creates a table out of it. I've read a lot of stuff using pggfor or etoolbox and more and I am kinda exhausted. Most of them are not easy to read and seem too complicated for a beginner.

\documentclass{article}
\begin{document}

\newcommand\createskill[2]{%
    \textsc{\textbf{#1}} & #2
}

\newcommand\createskills[1]{%
  \begin{tabular}{r|l}
    \makeatletter
    \@for\thisitem:=#1\do{\thisitem \\} %in the last iteration of loop a new line is added also 
    \makeatother
  \end{tabular}
}

% usage
\newcommand{\skillone}{\createskill{programming}{Python Java }}
\newcommand{\skilltwo}{\createskill{math}{Calculus Statistics}}
\createskills{\skillone, \skilltwo}
\end{document}

My problem is that because of \\ in the last iteration a new line is also added and I get a empty table row with only a sperator. I am open to suggestions to have a for loop that won't add this \\ in the last iteration.

I tried another solution with using \foreach command. Even though I got rid of the unnecessary \\ in the last row, this doesn't work well when contained within tabular environment.

\newcommand\createtablecontent[1]{%
    \foreach \x [count=\xi] in {#1} {\ifthenelse{\xi=1}{\x}{\\ \x}}
}

\newcommand\createskillsanothertry[1]{% called in the same way \createskills
    \begin{tabular}{r|l} 
      \createtablecontent{#1}
      \end{tabular}
}

with the above solution I only have the first row, and 22 warnings which seem quite complex.

If I exclude the tabular environment I have the desired behaviour of creating 2 lines of content.

\newcommand\createskillsanothertry[1]{%
      \createtablecontent{#1}
}

Answer 1

You can do it with expl3.

\documentclass{article}
\usepackage{xparse}

\ExplSyntaxOn

\NewDocumentCommand{\createskills}{m}
 {
  \begin{tabular}{r|l}
  \clist_map_function:nN { #1 } \irestmycase_skill:n
  \end{tabular}
 }

\cs_new_protected:Nn \irestmycase_skill:n
 {
  \tl_if_single:nTF { #1 }
   {
    \exp_last_unbraced:No \__irestmycase_skill_process:nn #1
   }
   {
    \__irestmycase_skill_process:nn #1
   }
 }
\cs_new_protected:Nn \__irestmycase_skill_process:nn
 {
  \textsc{#1} & #2 \\
 }

\ExplSyntaxOff

\begin{document}

% usage
\newcommand{\skillone}{{programming}{Python Java}}
\newcommand{\skilltwo}{{math}{Calculus Statistics}}
\createskills{\skillone, \skilltwo}

\bigskip

\createskills{
  {programming}{Python Java},
  {math}{Calculus Statistics}
}

\end{document}

Answer 2

We need not \directlua nor expl3 to solve this problem. The following solution is based only on TeX primitives:

\def\addto#1#2{\expandafter\def\expandafter#1\expandafter{#1#2}}
\def\skilllist{}
\def\createskill#1#2{\addto\skilllist{#1&#2\cr}}
\def\printskills{\vbox{\halign{\hfil\bf##\ \vrule\strut&\ ##\hfil\cr\skilllist}}}

\createskill{programming}{java python lua TeX}
\createskill{mathematics}{calculus statistics}
\createskill{languages}{english spanish korean}

\printskills

The \createskill macro adds the data to the internal \skillist in the form usable in \halign (table) parameter. And \printskills prints the table using \halign primitive and using the data from \skillist.

Answer 3

Using LuaLaTeX, in case this option is available, that's pretty easy. You only need two functions, \createskill and \printskill (you can rename them ad libitum). I've used TeX Gyre Schola only for displaying because it supports small caps.

%!TEX program = lualatex
%LuaLaTeX is mandatory here
\documentclass{standalone}
\usepackage{fontspec}
\setmainfont{TeX Gyre Schola}
\usepackage{luacode}
\begin{luacode*}
Skills = Skills or {}

function capitalise(str)
    local gmatch = unicode.utf8.gmatch
    local upper = unicode.utf8.upper
    local sub = unicode.utf8.sub
    local uppers = {}
    for w in str:gmatch("%S+") do
        table.insert(uppers, upper(sub(w,1,1))..sub(w,2))
    end
    return table.concat(uppers, " ")
end

function createskill(a,b)
    local str = [[\textbf{\textsc{]]..a..[[}} & ]]..capitalise(b)
    table.insert(Skills, str)
end

function printskills()
    tex.print([[\begin{tabular}{r|l}]])
    tex.print(table.concat(Skills, [[\\]]))
    tex.print([[\end{tabular}]])
end
\end{luacode*}
\newcommand{\createskill}[2]{\directlua{createskill("#1", "#2")}}
\newcommand{\printskills}{\directlua{printskills()}}
\begin{document}
%You add skills with this macro
\createskill{programming}{java python lua}
\createskill{mathematics}{calculus statistics}
\createskill{languages}{english spanish korean}
%And you print them all with this macro:
\printskills
\end{document}