案例选择函数的嵌套

Question

案例选择函数可以像\prg_case_int或一样\prg_case_str嵌套吗？如果可以，我将提供一些我观察到的嵌套非常奇怪的结果的示例。

修订：

interface3我省略了一些字符串，弄乱了文档中建议的语法<code case>。我的实验的修订代码现在可以正常工作，如下所示：

%document name: LaTeX3_interface3.tex
%RN 15/3/2012
%   OBJECTIVE: Nesting case-selecting functions prg_case_str or prg_case_int.
%   REFERENCE: The LaTeX3 Intefaces, 8 Feb 2012 (interface3.pdf), page 38ff.
%   COMMENTS: 
%   (1) on the first attempt failed to define all of the <code case> strings and the whole 
%   thing turned pear shaped
%   (2) the printed messages in the result are not properly formatted but that's due 
%   to my inexperience in LaTeX2 and needs to be addressed seperately.
%=====================================================================================

\documentclass{article}
%\usepackage{expl3}
\usepackage{amsmath,xparse} 
\ExplSyntaxOn 
\NewDocumentCommand{\myCommand}{ m m m } 
{ 
   \prg_case_str:nnn { #1 }
{
    {1a} 
    {
        \prg_case_str:nnn { #2 }
        {
            {2A} %{case 1a:2A\\}
            {
                \prg_case_str:nnn { #3 }
                {
                    {3\alpha}   {case 1a:2A:3\alpha\\}
                    {3\beta}    {case 1a:2A:3\beta\\}
                    {3\gamma}   {case 1a:2A:3\gamma\\}                  
                }
                    {None of 1a:2A: 3\alpha, 3\beta, 3\gamma \\}
            }
            {2B} %{case 1a:2B\\}
            {
                \prg_case_str:nnn { #3 }
                {
                    {3\alpha}   {case 1a:2B:3\alpha\\}
                    {3\beta}    {case 1a:2B:3\beta\\}
                    {3\gamma}   {case 1a:2B:3\gamma\\}                  
                }
                    {None of 1a:2B: 3\alpha, 3\beta, or 3\gamma\\}
            }
            {2C} %{case 1a:2C\\}
            {
                \prg_case_str:nnn { #3 }
                {
                    {3\alpha}   {case 1a:2C:3\alpha\\}
                    {3\beta}    {case 1a:2C:3\beta\\}
                    {3\gamma}   {case 1a:2C:3\gamma\\}                  
                }
                    {None of 1a:2C: 3\alpha, 3\beta, 3\gamma\\}
            }
        } 
            {None of 1a: 2A, 2B, 2C\\}
    }
    {1b} 
    {
        \prg_case_str:nnn { #2 }
        {
            {2A}    {case 1b:2A\\}
            {2B}    {case 1b:2B\\}
            {2C}    {case 1b:2C\\}
        } 
            {None of 1b: 2A, 2B, 2C\\}
    }
    {1c} 
    {
        \prg_case_str:nnn { #2 }
        {
            {2A}    {case 1c:2A\\}
            {2B}    {case 1c:2B\\}
            {2C}    {case 1c:2C\\}
        } 
            {None of 1c: 2A, 2B, 2C\\}
    }
}
    {None of 1a, 1b, 1c\\}
}
%etc. etc.
\ExplSyntaxOff 

\begin{document}

$\myCommand{1a}{2A}{3\alpha}$
$\myCommand{1a}{2B}{3\beta}$
$\myCommand{1a}{2C}{3\gamma}$
$\myCommand{1b}{2A}{3gamma}$
$\myCommand{1b}{2B}{3gamma}$
$\myCommand{1b}{2C}{3gamma}$
$\myCommand{x}{2A}{3gamma}$
$\myCommand{1a}{y}{3gamma}$
$\myCommand{1a}{2C}{3gamma}$
$\myCommand{1b}{2A}{3gamma}$
$\myCommand{z}{2B}{3gamma}$
$\myCommand{1b}{2C}{3gamma}$

\end{document}

如果我知道如何导入生成的 .pdf 文档我就会这么做。

抱歉，我又开始白费力气了。我唯一的借口是，在没有自动编辑工具的情况下，LaTeX 语法很难正确使用，而自动编辑工具至少可以生成正确的缩进。也许这样的 LaTeX3 编辑工具已经可用，如果有的话，我很想听听。