How can a new column type be defined, which feeds the column's contents (embraced) to a command?

Question

I am typesetting a document using the package tipa, and it happens often that the contents of each cell in a column of a table are notionally IPA and need to be enclosed between \textipa{ and }. So I want to define a column type which will add those enclosing strings.

I know the technique of using \newcolumntype from package array for enclosing such cell contents between two strings, e.g. \newcolumntype{M}{>{$}p<{$}} to supply math mode $'s. But what if a string to be added contains a backslash or a brace?

MNWE. Here, the \textipa disappears and I get literal braces. \backslash and \arraybackslash are to no avail.

    \documentclass[12pt,a4paper]{article}
    \usepackage{array} % for \newcolumntype
    \usepackage{tipa}
    \newcolumntype{I}{>{\textipa\{}c<{\}}}

    \begin{document}
    \begin{tabular}{I}
    lOrEm IpsUm
    \end{tabular}
    \end{document}

This question has been asked before: https://tex.stackexchange.com/q/504701/9632 — Sveinung, Apr 03 '20 at 15:34
you can use the collcell package https://tex.stackexchange.com/a/338866/2388 — Ulrike Fischer, Apr 03 '20 at 15:35
@Sveinung I saw that question, but couldn't understand its answer well enough to adapt it to my situation. — Rosie F, Apr 03 '20 at 16:16
@UlrikeFischer I found out how that could work for my situation. If you were to post it as an answer, I'd give it a +1 and a tick. — Rosie F, Apr 03 '20 at 16:26
if you found it out, you should answer your own question. After all you did the work, not me. — Ulrike Fischer, Apr 03 '20 at 16:27

score 0 · Answer 1 · answered Apr 03 '20 at 17:25

Thanks to Ulrike Fischer's referring me to this answer, I now find that the following does what I want. (I add two more columns, to show that the desired effect does not leak beyond the one column it is supposed to happen in.) Note that the braced expressions that follow > and < in the \newcolumntype command do not contain the braces which are meant to embrace the argument of \textipa.

\documentclass[12pt,a4paper]{article}
\usepackage{array} % for \newcolumntype
\usepackage{collcell}
\usepackage{tipa}

\newcolumntype{I}{>{\collectcell\textipa}c<{\endcollectcell}}

\begin{document}
\begin{tabular}{lIl}
left&lOrEm IpsUm&right
\end{tabular}
\end{document}

How can a new column type be defined, which feeds the column's contents (embraced) to a command?

1 Answers1