[Tex/LaTex] How to trim .tex for each filename read from an external file

external filesprogramming

I have an external text file that contains a list of names of TeX input files. The names have trailing extensions .tex.
For example, the external text file named data.txt contains the following list:

a.tex
b.tex
c.tex

There is a PDF file for each TeX input file in the same directory in which data.txt exists.

The following codes are expected to iterate the file name without extension and import the corresponding PDF.

\documentclass{article}
\usepackage{graphicx}

\begin{document}
\newread\reader
\immediate\openin\reader=data.txt\relax
\loop
    \read\reader to \x
    \unless\ifeof\reader
        \includegraphics{\x}\par
\repeat
\immediate\closein\reader
\end{document}

Could you help me to implement the trimming macro to remove .tex in \x?

Best Answer

The LaTeX2e kernel, provides some commands for parsing paths and extensions. It is preferable to use them for this type of parsing.

The macro \filename@parse scans its argument and splits it into three parts which are then saved in the macros \filename@area, \filename@base, \filename@ext

\documentclass{article}
\begin{document}
\makeatletter
\filename@parse{path/name.tex}
\filename@area, \filename@base, \filename@ext
\makeatother
\end{document}

In your case \filename@base will represent the trimmed filename, with no path or extension information.

Related Solutions

[Tex/LaTex] Put from external file

This may meet your needs. I found it at File input and output; I'm reproducing it (somewhat simplified) here:

With this sample fileOut.txt:

first line, with a \TeX{} macro to expand
second line
third line

the code

\documentclass{article}

\newread\file
\openin\file=fileOut.txt

\newcommand{\getnextline}{%
 \read\file to\fileline % Reads a line of the file into \fileline
 \fileline % display it
}

\begin{document}

First line of fileOut.txt: 

\getnextline{}

More text here, then second line: \getnextline{}

Third line: \getnextline{}

Read past end of file? \getnextline{}
\closein\file

\end{document}

produces

enter image description here

I hope this works for you in XeTeX with Arabic text.

Edit to answer the OP's further questions:

Since the example here works, the open and close statements are where they belong. Good programming practice (in any language) would call for checks that the file exists and is readable. I didn't do that since this answer is just a proof of concept. If you are in complete control of your environment and know the file will always be where it's expected, you need not bother.

I don't know what happens if you don't close an open file. I do know that TeX limits the number of files that you can have open at the same time. Some applications aren't good about releasing file handles by themselves, so it's a good habit to close them yourself.

I was curious about what would happen if I read past the end of the file. The example shows that reading a line that's not there just returns an empty string. You need to decide whether that's acceptable in your use case. If not, test for eof and act accordingly.

[Tex/LaTex] Read integers from external data file to document programming code in LaTeX

In my opinion, it would be simpler and more robust to just use linerange markers for listings in comments of your m-file. See the example below. I used the matlab-prettifier package instead of mcode, but the approach should work with either.

Basically, you define a prefix for those linerange markers with the rangeprefix key; here, the prefix I use is simply a percent character (%) followed by a space character:

rangeprefix=\%\ ,

Note that both of those characters must be escaped here (but not in your MATLAB code). Then, in your code, you use a pair of descriptive strings to mark the start and end of each of the ranges of interest. In the example below, I used param and endparam for the first range of interest, and param2 and endparam2 for the second range of interest. Make sure to use

includerangemarker=false

if you don't want the markers themselves to appear in the output.

You can find more details about those linerange markers in subsection 5.7 of the listings manual.

enter image description here

\documentclass{article}

\usepackage[T1]{fontenc}
\usepackage{matlab-prettifier}

\usepackage{filecontents}
\begin{filecontents*}{sample.m}
foo=3
bar=5
baz=foo
foo=bar
bar=baz
% param
% first set of parameters
alpha=10; % PDE parameter.
x_s=0; % Starting coordinate.
x_e=1; % End coordinate.
N_n=1e2+1; % (N)umber of (n)odes.
N_ip=2; % (N)umber of (i)ntegration (p)oints.
% endparam
clear baz
% param2
% second set of parameters
beta=20;
N = 42;
% endparam2
\end{filecontents*}

\lstset{
  style              = Matlab-editor,
  basicstyle         = \mlttfamily,
  rangeprefix        = \%\ ,
  includerangemarker = false,
}

\begin{document}
\lstinputlisting[linerange=param-endparam]{sample.m}
\lstinputlisting[linerange=param2-endparam2]{sample.m}
\end{document}

Best Answer

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[Tex/LaTex] Put from external file

[Tex/LaTex] Read integers from external data file to document programming code in LaTeX

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