获取当前源代码行号

Question

如何获取当前 .tex 源代码行号？我想使用它在我正在编写的包中生成有用的错误消息。

有些错误只能在文档末尾检测到，所以我想创建一个命令来检查这些错误并告诉错误发生在哪一行。为此，我需要能够保存错误应用的命令中的源代码行号。

\sourcelineno最好是可以像本例中一样使用的命令：

\documentclass{minimal}
\newcommand \showlineno {line \sourcelineno}

\begin{document}

You are now at \showlineno.

This paragraph starts at \showlineno, and 
some more text,
and runs until \showlineno. 

\end{document}

输出结果为

You are now at line 6.

This paragraph starts at line 8, and some more text, and runs until line 10. 

Answer 1

您可以使用内核的变体\on@line：

\documentclass{article}

\makeatletter
\ifnum\inputlineno=\m@ne
\let\showlineno\@empty
\else
\def\showlineno{ line \the\inputlineno}
\fi
\makeatother

\begin{document}

You are now at \showlineno.

This paragraph starts at \showlineno, and 
some more text,
and runs until \showlineno.

on input line \the\inputlineno

\end{document}

Answer 2

Gonzalo 答案的 LuaLaTeX 变体，作为用法的介绍性示例\directlua。

\documentclass{article}

\def\showlineno{
  line \directlua{tex.print(tex.inputlineno)}%
}

\begin{document}

You are now at \showlineno.

This paragraph starts at \showlineno, and 
some more text,
and runs until \showlineno.

on input line \the\inputlineno

\end{document}

奇怪的行号不受管理。