LaTeX 计算参数中出现的次数

Question

我一直在尝试计算字符串中的特定字符（我定义的新环境的一个参数）。我遇到了这问题，其中一个答案为我指明了正确的方向。虽然我能够根据自己的需要调整建议的方法，但又出现了一个新问题：Missing number, treated as zero. <read again> \xparse function is not expandable。

为了使建议的代码最初起作用，我必须将新环境的参数分配给像这样的宏\def\labelvalue{#1}\def\coloncount{\countin*{:}{\labelvalue}}。

打印结果工作正常并给出正确的结果，但不幸的是，当我尝试将结果与整数进行比较时，会抛出上述错误，例如\ifnum \coloncount=1。我发现这在网上，链接到我所关注的答案，但我没有让他们的建议发挥作用。

目的是定义一个根据传递的标签输出不同文本的环境。由于标签都是按照相同方案 (rq:x 或 rq:x:y) 构造的，因此将根据冒号的数量来决定要进行哪种输出。

该文档是使用 latexmk 和所有使用的软件包的最新版本编译的。

\ExplSyntaxOn
% source: https://tex.stackexchange.com/a/525246/96582
\NewDocumentCommand{\countin}{smm}
{% #1 = * if searching in a macro
    % #2 = string to search
    % #3 = token list to search in
    \IfBooleanTF { #1 }
    {
        \bruoga_countin:nV { #2 } #3
    }
    {
        \bruoga_countin:nn { #2 } { #3 }
    }
}
\cs_new_protected:Nn \bruoga_countin:nn
{
    \regex_count:nnN { #1 } { #2 } \l_tmpa_int
    \int_to_arabic:n { \l_tmpa_int }
}
\cs_generate_variant:Nn \bruoga_countin:nn { nV }
\ExplSyntaxOff

% ...

% define environment <hypothesis>
\newenvironment{hypothesis}[1]{%
    % #1 -> the label of the research question or subquestion it belongs to, e.g. rq:1 or rq:1.1
    \def\refno{\getrefnumber{#1}} % value of the reference (if provided) or 0
    \ifnum \refno=0% reference number is 0; missing label or new counter
        \textcolor{red}{THE PROVIDED (SUB)QUESTION LABEL DOES NOT EXIST!}
    \else%
        % this hypothesis could belong to a main or a subquestion. Since all labels are structured the same, check the provided label
        \def\labelvalue{#1} % #1 needs to be defined as macro for \countin to work!
        \def\coloncount{\countin*{:}{\labelvalue}}
        \coloncount
        \ifnum \coloncount=1% main question
            level1
        \else%
            \ifnum \coloncount=2% sub question
                level2
            \else%error
                \textcolor{red}{THE PROVIDED (SUB)QUESTION LABEL IS NOT VALID!}
            \fi
        \fi
    \fi
}{% at the end of the environment
    \par
}

Answer 1

您不需要链接问题中的命令的全部功能。

\documentclass{article}
\usepackage{refcount,xcolor}

\ExplSyntaxOn

% define environment <hypothesis>
\NewDocumentEnvironment{hypothesis}{m}
 {% #1 -> the label of the research question or subquestion it belongs to, e.g. rq:1 or rq:1.1
  \int_compare:nTF { \getrefnumber{#1} = 0 }
   {% the label doesn't exist yet, or a rerun is needed
    \textcolor{red}{THE ~ PROVIDED ~ (SUB)QUESTION ~ LABEL ~ DOES ~ NOT ~ EXIST!}
   }
   {% this hypothesis could belong to a main or a subquestion.
    \regex_count:nnN { : } { #1 } \l_tmpa_int
    %  Since all labels are structured the same, check the provided label
    \int_case:nnF { \l_tmpa_int }
     {
      {0}{level0}
      {1}{level1}
      {2}{level2}
     }
     {% error
      \textcolor{red}{THE ~ PROVIDED ~ (SUB)QUESTION ~ LABEL ~ IS ~ NOT ~ VALID!}
     }
   }
 }
 {% at the end of the environment
  \par
 }

\ExplSyntaxOff

\newcounter{test}

\begin{document}

\refstepcounter{test}\label{x}
\refstepcounter{test}\label{x:y}
\refstepcounter{test}\label{x:y:z}
\refstepcounter{test}\label{x:y:z:w}

\begin{hypothesis}{x}
Some text
\end{hypothesis}

\begin{hypothesis}{x:y}
Some text
\end{hypothesis}

\begin{hypothesis}{x:y:z}
Some text
\end{hypothesis}

\begin{hypothesis}{x:y:z:w}
Some text
\end{hypothesis}

\end{document}