为序列/列表/元组宏定义宏

Question 1

这是一个expl3带有变量的版本seq。

该命令\NewListCommand声明了与第一个参数同名的命令列表宏，并使用了seq带有某些前缀的全局变量，参见\g_cryingshadow_mynewlist_seq等等。

这是由\mynewlist命令填充的，并且根据从#3到#6的其他参数的内容显示内容。第7个参数用作分隔符

一些注意事项：该empty参数可以是可选的。

\documentclass{article}


\usepackage{xparse}

\ExplSyntaxOn
\NewDocumentCommand{\NewListCommand}{mmmmmmm}{%
  \seq_new:c {g_cryingshadow_#1_seq} % Make a new sequence
  \expandafter\NewDocumentCommand\csname #1\endcsname{m}{%
    \seq_gclear:c {g_cryingshadow_#1_seq}% Clear the sequence
    \seq_gclear:N \l_tmpa_seq % Clear a temporary `\l_tmpa_seq
    \seq_set_split:Nnn \l_tmpa_seq {} {##1} % Split the sequence into tokens. 
    \seq_set_eq:cN {g_cryingshadow_#1_seq} \l_tmpa_seq % copy the temporary sequence to the real one → this would not be necessary if the sequence is not be used outside 
    \seq_if_empty:cTF {g_cryingshadow_#1_seq} {%
      #2% Checked --> is empty
    }{%
      % Display the various styles
      \int_case:nn { \seq_count:c {g_cryingshadow_#1_seq} }
      {%
        {1} {#3      \seq_use:cnnn {g_cryingshadow_#1_seq} {,} {#7} {#7} #4}
      }%
      \int_compare:nNnT { \seq_count:c {g_cryingshadow_#1_seq}}  > 1 {%
        #5      \seq_use:cnnn {g_cryingshadow_#1_seq} {#7} {#7} {#7} #6
      }
    }
  }
}
\ExplSyntaxOff


\NewListCommand{mynewlist}{empty}{[}{]}{(}{)}{,}


\begin{document}

\mynewlist{{A}{B}{C}}

\mynewlist{{A}{B}}

\mynewlist{{a}}

\mynewlist{}


\mynewlist{{A}{B}{C}{D}{E}{F}}


Astronomer's alphabet:

\mynewlist{{Oh}{be}{a}{fine}{girl}{kiss}{me}}

\end{document}

编辑：这是通常的 LaTeX 的工作版本：

\documentclass{article}
\usepackage{etoolbox}

\makeatletter

\def\definelistcommand#1#2#3#4#5#6#7{%

  \expandafter\def\csname @firstinlist#1\endcsname##1{%
    \@ifnextchar\@stoplist{%
      #3##1#4\@endlist%
    }{%
      #5##1\csname @nextlist#1\endcsname%
    }%
  }

  \expandafter\def\csname @nextlist#1\endcsname##1{%
    \@ifnextchar\@stoplist{%
      #7##1#6\@endlist%
    }{%
      #7##1\csname @nextlist#1\endcsname%
    }%
  }


  \expandafter\def\csname @startlist#1\endcsname##1{%
    \@ifnextchar\@stoplist{%
      #3##1#4\@endlist%
    }{%
      \csname @firstinlist#1\endcsname##1% 
    }%
  }

  \expandafter\def\csname #1\endcsname##1{%
    \ifblank{##1}{%
      #2%
    }{%
      \csname @startlist#1\endcsname##1\@stoplist%
    }%
  }
}

\def\@endlist#1{}


\definelistcommand{mycmd}{empty}{[}{]}{(}{)}{,}

\definelistcommand{othercmd}{empty}{\textbraceleft}{\textbraceright}{(}{)}{+}

\begin{document}


\makeatother

\mycmd{{A}{B}{C}}

\mycmd{A}

\mycmd{{A}{B}}

\mycmd{}

\othercmd{{O}{B}}

\othercmd{{O}}


\end{document}

Answer

这是一个expl3带有变量的版本seq。

该命令\NewListCommand声明了与第一个参数同名的命令列表宏，并使用了seq带有某些前缀的全局变量，参见\g_cryingshadow_mynewlist_seq等等。

这是由\mynewlist命令填充的，并且根据从#3到#6的其他参数的内容显示内容。第7个参数用作分隔符

一些注意事项：该empty参数可以是可选的。

\documentclass{article}


\usepackage{xparse}

\ExplSyntaxOn
\NewDocumentCommand{\NewListCommand}{mmmmmmm}{%
  \seq_new:c {g_cryingshadow_#1_seq} % Make a new sequence
  \expandafter\NewDocumentCommand\csname #1\endcsname{m}{%
    \seq_gclear:c {g_cryingshadow_#1_seq}% Clear the sequence
    \seq_gclear:N \l_tmpa_seq % Clear a temporary `\l_tmpa_seq
    \seq_set_split:Nnn \l_tmpa_seq {} {##1} % Split the sequence into tokens. 
    \seq_set_eq:cN {g_cryingshadow_#1_seq} \l_tmpa_seq % copy the temporary sequence to the real one → this would not be necessary if the sequence is not be used outside 
    \seq_if_empty:cTF {g_cryingshadow_#1_seq} {%
      #2% Checked --> is empty
    }{%
      % Display the various styles
      \int_case:nn { \seq_count:c {g_cryingshadow_#1_seq} }
      {%
        {1} {#3      \seq_use:cnnn {g_cryingshadow_#1_seq} {,} {#7} {#7} #4}
      }%
      \int_compare:nNnT { \seq_count:c {g_cryingshadow_#1_seq}}  > 1 {%
        #5      \seq_use:cnnn {g_cryingshadow_#1_seq} {#7} {#7} {#7} #6
      }
    }
  }
}
\ExplSyntaxOff


\NewListCommand{mynewlist}{empty}{[}{]}{(}{)}{,}


\begin{document}

\mynewlist{{A}{B}{C}}

\mynewlist{{A}{B}}

\mynewlist{{a}}

\mynewlist{}


\mynewlist{{A}{B}{C}{D}{E}{F}}


Astronomer's alphabet:

\mynewlist{{Oh}{be}{a}{fine}{girl}{kiss}{me}}

\end{document}

编辑：这是通常的 LaTeX 的工作版本：

\documentclass{article}
\usepackage{etoolbox}

\makeatletter

\def\definelistcommand#1#2#3#4#5#6#7{%

  \expandafter\def\csname @firstinlist#1\endcsname##1{%
    \@ifnextchar\@stoplist{%
      #3##1#4\@endlist%
    }{%
      #5##1\csname @nextlist#1\endcsname%
    }%
  }

  \expandafter\def\csname @nextlist#1\endcsname##1{%
    \@ifnextchar\@stoplist{%
      #7##1#6\@endlist%
    }{%
      #7##1\csname @nextlist#1\endcsname%
    }%
  }


  \expandafter\def\csname @startlist#1\endcsname##1{%
    \@ifnextchar\@stoplist{%
      #3##1#4\@endlist%
    }{%
      \csname @firstinlist#1\endcsname##1% 
    }%
  }

  \expandafter\def\csname #1\endcsname##1{%
    \ifblank{##1}{%
      #2%
    }{%
      \csname @startlist#1\endcsname##1\@stoplist%
    }%
  }
}

\def\@endlist#1{}


\definelistcommand{mycmd}{empty}{[}{]}{(}{)}{,}

\definelistcommand{othercmd}{empty}{\textbraceleft}{\textbraceright}{(}{)}{+}

\begin{document}


\makeatother

\mycmd{{A}{B}{C}}

\mycmd{A}

\mycmd{{A}{B}}

\mycmd{}

\othercmd{{O}{B}}

\othercmd{{O}}


\end{document}

Question 2

你可以尝试这个宏：

\newcount\tmpnum
\def\definelistcommand#1#2#3#4#5#6#7{%
   \expandafter\def\csname\string#1:list\endcsname##1{%
      \ifcase##1 #2\or#3\or#4\or#5\or#6\or#7\fi}%
   \def#1{\dolist#1}%
}
\def\dolist#1#2{\tmpnum=0 \def\tmp{}%
   \def\listcommand{\csname\string#1:list\endcsname}%
   \dolistA#2\end}
\def\dolistA#1{%
   \ifx\end#1%
      \ifnum\tmpnum=0 \listcommand0%
      \else\ifnum\tmpnum=1 \listcommand1\tmp\listcommand2%
      \else \listcommand3\tmp\listcommand4%
      \fi\fi
   \else\edef\tmp{\ifx\tmp\empty\else\tmp\listcommand5\fi#1}%
      \advance\tmpnum by1
      \expandafter\dolistA\fi
}

\definelistcommand \mylist {empty} [](),

\mylist{{a}{b}{c}}

\mylist{{a}{b}}

\mylist{a}

\mylist{{b}}

\mylist{}

解释。\definelistcommand\foo定义了两个控制序列。第一个\\foo:list为\ifcase。它扩展了适当的声明参数：\\foo:list0扩展到nothing、\\foo:list1等[。第二个定义的控制序列是\foo。这是宏\dolist\foo。

的用法\foo{text}扩展为\dolist\foo{text}。此宏重置\tmp为空，\tmpnum为零并保存\listcommand为\\foo:list。然后它运行\dolistA text\end。

重复读取\dolistA文本中的项。它\tmp使用将这些项保存到宏中\edef\tmp。如果不为空，则在前一个内容和下一个项之间添加\tmp逗号（别名）。计算项数。当达到时，根据值打印。\listcommand5#1\tmpnum\end\tmp\tmpnum

请注意，我们不需要任何外部包，我们可以非常简单地声明类似列表的宏。

Answer

你可以尝试这个宏：

\newcount\tmpnum
\def\definelistcommand#1#2#3#4#5#6#7{%
   \expandafter\def\csname\string#1:list\endcsname##1{%
      \ifcase##1 #2\or#3\or#4\or#5\or#6\or#7\fi}%
   \def#1{\dolist#1}%
}
\def\dolist#1#2{\tmpnum=0 \def\tmp{}%
   \def\listcommand{\csname\string#1:list\endcsname}%
   \dolistA#2\end}
\def\dolistA#1{%
   \ifx\end#1%
      \ifnum\tmpnum=0 \listcommand0%
      \else\ifnum\tmpnum=1 \listcommand1\tmp\listcommand2%
      \else \listcommand3\tmp\listcommand4%
      \fi\fi
   \else\edef\tmp{\ifx\tmp\empty\else\tmp\listcommand5\fi#1}%
      \advance\tmpnum by1
      \expandafter\dolistA\fi
}

\definelistcommand \mylist {empty} [](),

\mylist{{a}{b}{c}}

\mylist{{a}{b}}

\mylist{a}

\mylist{{b}}

\mylist{}

解释。\definelistcommand\foo定义了两个控制序列。第一个\\foo:list为\ifcase。它扩展了适当的声明参数：\\foo:list0扩展到nothing、\\foo:list1等[。第二个定义的控制序列是\foo。这是宏\dolist\foo。

的用法\foo{text}扩展为\dolist\foo{text}。此宏重置\tmp为空，\tmpnum为零并保存\listcommand为\\foo:list。然后它运行\dolistA text\end。

重复读取\dolistA文本中的项。它\tmp使用将这些项保存到宏中\edef\tmp。如果不为空，则在前一个内容和下一个项之间添加\tmp逗号（别名）。计算项数。当达到时，根据值打印。\listcommand5#1\tmpnum\end\tmp\tmpnum

请注意，我们不需要任何外部包，我们可以非常简单地声明类似列表的宏。

Question 3

我认为，与使用一长串参数相比，使用键值语法更好。

\documentclass{article}
\usepackage{xparse}

\ExplSyntaxOn

\NewDocumentCommand{\definelistcommand}{mm}
 {% #1 is the command name, #2 is the key-value setup
  % clear the temporary property list
  \prop_clear:N \l_cryingshadow_list_temp_prop
  \keys_set:nn { cryingshadow/list } { #2 }
  % check if left-single or right-single have been set
  \prop_if_in:NnF \l_cryingshadow_list_temp_prop { left-single }
   {
    \prop_put:Nnx \l_cryingshadow_list_temp_prop { left-single }
     { \prop_item:Nn \l_cryingshadow_list_temp_prop { left } }
   }
  \prop_if_in:NnF \l_cryingshadow_list_temp_prop { right-single }
   {
    \prop_put:Nnx \l_cryingshadow_list_temp_prop { right-single }
     { \prop_item:Nn \l_cryingshadow_list_temp_prop { right } }
   }
  % allocate a specific property list and make it equal to the temporary one
  \prop_new:c { g_cryingshadow_list_#1_prop }
  \prop_gset_eq:cN { g_cryingshadow_list_#1_prop } \l_cryingshadow_list_temp_prop
  % define the runtime macro to call the generic one with the current name as argument
  \cs_new_protected:cpn { #1 } ##1 { \cryingshadow_list_print:nn { #1 } { ##1 } }
 }

% allocate some variables
\prop_new:N \l_cryingshadow_list_temp_prop
\seq_new:N \l_cryingshadow_list_input_seq

% syntactic sugar
\cs_new_protected:Nn \__cryingshadow_list_put:nn
 {
  \prop_put:Nnn \l_cryingshadow_list_temp_prop { #1 } { #2 }
 }
\cs_new_protected:Nn \__cryingshadow_list_item:nn
 {
  \prop_item:cn { g_cryingshadow_list_#1_prop } { #2 }
 }

% define the keys
\keys_define:nn { cryingshadow/list }
 {
  empty .code:n = \__cryingshadow_list_put:nn { empty } { #1 },
  left-single .code:n = \__cryingshadow_list_put:nn { left-single } { #1 },
  right-single .code:n = \__cryingshadow_list_put:nn { right-single } { #1 },
  left .code:n = \__cryingshadow_list_put:nn { left } { #1 },
  right .code:n = \__cryingshadow_list_put:nn { right } { #1 },
  delimiter .code:n = \__cryingshadow_list_put:nn { delimiter } { #1 },
 }

\cs_new_protected:Nn \cryingshadow_list_print:nn
 {
  % split the input into items at commas
  \seq_set_split:Nnn \l_cryingshadow_list_input_seq { , } { #2 }
  % branch between empty or single and multiple items
  \int_compare:nTF { \seq_count:N \l_cryingshadow_list_input_seq = 1 }
   {
    % if the sequence has just one item it could be empty
    \tl_if_blank:nTF { #2 }
     { \__cryingshadow_list_item:nn { #1 } { empty } }
     {
      \__cryingshadow_list_item:nn { #1 } { left-single }
      #2
      \__cryingshadow_list_item:nn { #1 } { right-single }
     }
   }
   {
    % otherwise it has multiple items
    \__cryingshadow_list_item:nn { #1 } { left }
    \seq_use:Nn \l_cryingshadow_list_input_seq { \__cryingshadow_list_item:nn { #1 } { delimiter } }
    \__cryingshadow_list_item:nn { #1 } { right }
   }
 }

\ExplSyntaxOff

\definelistcommand{firstlist}{
  empty=empty,
  left-single=[,
  right-single=],
  left=(,
  right=),
  delimiter={, },
}
\definelistcommand{secondlist}{
  empty=nothing,
  left=\{,
  right=\},
  delimiter={--},
}

\begin{document}

\firstlist{A,B,C}

\firstlist{A,B}

\firstlist{a}

\firstlist{}

\secondlist{A,B,C}

\secondlist{A,B}

\secondlist{a}

\secondlist{}

\end{document}

这是如何运作的？

第\definelistcommand一个设置了一个特定于要定义的列表命令的属性列表，其中存储了各个项目（外部分隔符、内部分隔符、空情况的处理方式）；然后它定义宏来调用通用函数来产生输出。

通过检查第二个参数为属性列表提供值。如果未指定left-single或，则提供或的right-single值。leftright

在调用时，通用宏从特定属性列表中获取值，用逗号分隔参数，然后分支：如果参数为空，则打印案例的值；如果只有一项，则使用left-single和right-single外部分隔符；否则使用left和right，并在项之间使用内部分隔符。

Answer