[Tex/LaTex] How to extend the \lstinputlisting command

hookslistingspackage-writing

With the answer from autogobble for lstinputlistings
I've managed to create a command that gobbles \lstinputlisting and makes firstnumber to start by firstline. I would like to rewrite it as a package, so it hooks into \lstinputlisting, but as the code might reflect I have very little experience with programming in LaTeX.

My goal is to be able to write

\lstset{tabsize=3,numbers=left,frame=single,basicstyle=\footnotesize\ttfamilily,}
\lstinputlisting[levels=1,linerange={2-4},...]{hello.c}

where the dots are possible extra regular listings options.

or what could be even more nice:

\lstset{tabsize=3,numbers=left,frame=single,basicstyle=\footnotesize\ttfamilily,}
\lstinputlisting[autogobble,linerange={2-4},...]{hello.c}

where LaTeX automatically counted the number of tabs like in How to automatically skip leading white spaces in listings

MWE

\documentclass{article}
\usepackage{listings,xifthen}

\lstset{tabsize=3,numbers=left,frame=single,basicstyle=\Huge\ttfamily,columns=flexible}
\newlength{\gobble}
\newlength{\gobblea}
% The width of a single space. basicstyle from lstset should be used
\sbox0{\Huge\ttfamily \ }
\newcommand{\mylist}[5]{
%#1 is number of tabs, could be calculated like in listings-autogobble with autogobble=true or be an extra option
%#2 is tabsize, which is set in lstset
%#3 is firstline from lstset
%#4 is lastline from lstset
%#5 is the filename, the only thing which should be an argument and not an option.

% Remove a single space
\setlength{\gobble}{-\the\wd0}
% Reindent a bit by multiplying with 0.9, then multiply by tabsize and number of indentation levels
\setlength{\gobble}{0.9\gobble*#1*#2}
\setlength{\gobblea}{\gobble}
\addtolength{\gobblea}{10pt}
% Check if firstline is defined
\ifthenelse{\isempty{#3} \OR \equal{#3}{0}}{%
% Check if lastline is defined
\ifthenelse{\isempty{#4}}{%
\lstinputlisting[firstnumber=1,firstline=1,framexleftmargin=\gobble,xleftmargin=\gobble,numbersep=\gobblea]{#5}
}{
\lstinputlisting[firstnumber=1,firstline=1,lastline=#4,framexleftmargin=\gobble,xleftmargin=\gobble,numbersep=\gobblea]{#5}
}
}{
\ifthenelse{\isempty{#4}}{%
\lstinputlisting[firstnumber=#3,firstline=#3,framexleftmargin=\gobble,xleftmargin=\gobble,numbersep=\gobblea]{#5}
}{
\lstinputlisting[firstnumber=#3,firstline=#3,lastline=#4,framexleftmargin=\gobble,xleftmargin=\gobble,numbersep=\gobblea]{#5}
}
}
}
\begin{document}
%mylist{#tabs}{#tabsize}{firstline}{lastline}{filename}
\mylist{1}{3}{2}{4}{hello1.c}
\end{document}

edit:

I just modified the code from cyberSingularity a bit to use lst@basicstyle and lst@tabsize.

It should work with any:

  • font size in document class
  • font size in basicstyle
  • tabsize

Limitations (Would be very pleased if someone could address these limitations):

  • It needs columns=flexible and basicstyle=\ttfamily.
  • If tabsize or basicstyle is passed as options to \lstinputlisting, they must be written before widthgobble.
  • If using XeLaTeX, the commands must be loaded before Polyglossia, othwerwise all text will be formatted with \ttfamily

    • \documentclass[10pt]{article}
    \usepackage{listings}

    \usepackage{filecontents}
\begin{filecontents*}{hello1.c}
if (a<b){
   if (b<a){
      printf("hello")
   }
}
\end{filecontents*}

\lstset{tabsize=3,numbers=left,frame=single,basicstyle=\Huge\ttfamily,columns=flexible}

\makeatletter
\newlength{\singlespace}
\newlength{\gobble}
\newlength{\numbersep}
% The width of a single space.
\settowidth{\singlespace}{\lst@basicstyle \ }
\setlength{\singlespace}{-\singlespace}

\lst@Key{firstlineandnumber}\relax{\def\lst@firstline{#1\relax}\def\lst@firstnumber{#1\relax}}
\lst@Key{widthgobble}{0}{%
    \setlength{\gobble}{0.9\singlespace}% reindent a bit
    \setlength{\gobble}{\lst@tabsize\gobble}% multiply by tabsize
    \setlength{\gobble}{#1\gobble}% multiply by number of tabs
    \def\lst@xleftmargin{\gobble}% move left margin left
    \def\lst@framexleftmargin{\gobble}% move left frameborder left
    \setlength{\numbersep}{\gobble}%
    \addtolength{\numbersep}{10pt}%
    \def\lst@numbersep{\numbersep}% distance between numbers and left frameborder
}
\makeatother

\begin{document}
%widthgobble=#tabs,firstlineandnumber sets firstline and firstnumber
\lstinputlisting[widthgobble=1,firstlineandnumber=2,lastline=4]{hello1.c}
\end{document}

    Best Answer

    Are you after something like this? I have provided new keys:

    • widthgobble, which takes as an argument #tabs*#tabsize
    • firstlineandnumber, which sets both firstline and firstnumber

    Note that I had some trouble using the * syntax for setting the length of \gobble so have implemented an ugly workaround (which currently means that the argument to widthgobble should always have two numbers separated by an asterisk):

    \documentclass{article}
\usepackage{listings}

\usepackage{filecontents}
\begin{filecontents*}{hello1.c}
if (a<b){
    if (b<a){
        //do something
    }
}
\end{filecontents*}

\errorcontextlines=\maxdimen

\lstset{tabsize=3,numbers=left,frame=single,basicstyle=\Huge\ttfamily,columns=flexible}
\newlength{\rawgobble}
\newlength{\gobble}
\newlength{\gobblea}
% The width of a single space. basicstyle from lstset should be used
\sbox0{\Huge\ttfamily \ }
% Remove a single space
\settowidth{\rawgobble}{\Huge\ttfamily \ }
\setlength{\rawgobble}{-\rawgobble}

\makeatletter
\def\sepstar#1*#2\relax{%
    \def\sepstarone{#1}%
    \def\sepstartwo{#2}%
}
\lst@Key{firstlineandnumber}\relax{\def\lst@firstline{#1\relax}\def\lst@firstnumber{#1\relax}}
\lst@Key{widthgobble}{0*0}{%
    % Reindent a bit by multiplying with 0.9, then multiply by tabsize and number of indentation levels
    \sepstar #1\relax
    \setlength{\gobble}{0.9\rawgobble}%
    \setlength{\gobble}{\sepstarone\gobble}%
    \setlength{\gobble}{\sepstartwo\gobble}%
    \setlength{\gobblea}{\gobble}%
    \addtolength{\gobblea}{10pt}%
    \def\lst@xleftmargin{\gobble}%
    \def\lst@framexleftmargin{\gobble}%
    \def\lst@numbersep{\gobblea}%
}
\makeatother

\begin{document}
%widthgobble=#tabs*#tabsize,firstlineandnumber sets firstline and firstnumber
\lstinputlisting[widthgobble=1*3,firstlineandnumber=2,lastline=4]{hello1.c}
\end{document}
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