Input multi files at one time by \foreach

Question

I have several files in the sub-folder ./tmp -- "a.tex" whose content is \def\aaa{aaa}, "b.tex" whose content is `\def\bbb{bbb}.

Then I input them to my main doc at one time by \foreach, as the following code tries, but it fails to work, and causes error message Undefined control sequence..

What shall I do?

Code:

\documentclass{article}
\usepackage{pgffor}
\foreach \x in {a.tex,b.tex}{
  \input{tmp/\x}
  }
\begin{document}
\aaa\bbb
\end{document}

How to \gdef \input? Or are there any better methods than \foreach? — lyl, Jun 15 '22 at 03:27
\newcommand was use \def, you could use \let\olddef\def \let\def\gdef \newcommand... \let\def\olddef — Tom, Jun 15 '22 at 03:43
I don't want to redefine \def as it relates many other things. It seems that \foreach in my example is not a good idea. Any other better methods for this question? — lyl, Jun 15 '22 at 04:07
Maybe \global\let\aaa\aaa. There isn't really a non-hacky way I guess. — user202729, Jun 15 '22 at 04:08
macros - \global\renewcommand equivalent of \global\def - TeX - LaTeX Stack Exchange — user202729, Jun 15 '22 at 04:08
There are many things and definations in those files which will be included in my main doc. I don't want to modify them one by one. So I have to give up \foreach and look forward to other better ways. — lyl, Jun 15 '22 at 04:22

score 3 · Answer 1 · answered Jun 16 '22 at 05:37

3

The simplest way around the problem is to use OpTeX. It provides ts own expandable \foreach without inserting groups:

\foreach{a.tex}{b.tex}\do{\input{tmp/#1}}

If you are not using OpTeX then you can create your own macro using TeX primitives:

\def\forfiles#1{\ifx\relax#1\else \input{tmp/#1}\expandafter\forfiles\fi}
\forfiles{a.tex}{b.tex}\relax

You need not any expl3. The proposed solution uses no grouping.

answered Jun 16 '22 at 05:37

wipet

74,238

Elegant solution! Thank you. And how to modify it to make tmp as an optional argument? – lyl Jun 16 '22 at 07:21

Tom · Answer 2 · 2022-06-15T05:02:59.297

1

I am also new to latex3. This is a method to manipulating items in token lists.

\begin{filecontents*}{a.tex}
\def\aaa{aaa}
\newcommand{\ddd}{ddd}
\end{filecontents*}
\begin{filecontents*}{b.tex}
\def\bbb{bbb}
\end{filecontents*}
\begin{filecontents*}{c.tex}
\def\ccc{ccc}
\end{filecontents*}
\documentclass{article}
\ExplSyntaxOn
\tl_new:N \tl__myfiles
\tl_set:Nn \tl__myfiles {{a.tex}{b.tex}{c.tex}}
\tl_map_variable:NNn \tl__myfiles \x {\input{\x}}
\ExplSyntaxOff
\begin{document}
\aaa\bbb\ccc\ddd
\end{document}

edited Jun 15 '22 at 05:02

answered Jun 15 '22 at 04:58

Tom

7,318
4
21

By convention it's called latex3, not latex3e. – muzimuzhi Z Jun 15 '22 at 05:02
@muzimuzhiZ changed – Tom Jun 15 '22 at 05:03

score 1 · Accepted Answer · answered Jun 15 '22 at 10:22

The simplest way around the problem is to use expl3:

\documentclass{article}
\ExplSyntaxOn
\NewDocumentCommand{\multiinput}{O{.}m}
 {% #1 = common prefix, default . for the current directory
  % #2 = list of file names
  \clist_map_inline:nn { #2 } { \input{#1/##1} }
 }
\ExplSyntaxOff
\begin{document}
\multiinput[tmp]{a,b}
\fooA
\fooB
\end{document}

In the subdirectory tmp I put

% file a.tex
\newcommand{\fooA}{A}
\fooA

and

% file b.tex
\newcommand{\fooB}{B}
\fooB

Compiling the main file above produces

With \foreach every cycle in the loop is processed inside a group, which is the reason why definitions inside the \input files don't survive. The proposed solution uses no grouping.

Input multi files at one time by \foreach

3 Answers3

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