无法使 tikz 中的条件样式起作用

Question

我定义了一个宏\chooseStyle{text}{styleA}{styleB}，它根据文本在styleA和之间进行选择（它只是返回好的样式）。我尝试使用以下方法将其合并到 tikz 样式中：styleB

  styleA/.style={...},
  styleA/.style={...},
  choose/.code={
    \tikzset{\chooseStyle{#1}{styleA}{styleB}}
  }

但它失败了（就像许多其他尝试一样）并出现错误。出了什么问题？

平均能量损失

\documentclass{article}
\usepackage{amsmath}
\usepackage{etoolbox}
\usepackage{tikz}
\usepackage{tikz-cd}
\usepackage{ifthen}

% Small minus. Feel free to redefine.
\usepackage{amssymb}
\DeclareMathSymbol{\zxMinus}{\mathbin}{AMSa}{"39} % Requires amssymb
\tikzset{
  %% Can be redefined by user
  % Style for empty nodes
  styleA/.style={fill=green},
  % Style for nodes that are small enough to fit in a circle, like $\zxMinus \frac{\pi}{4}$
  styleB/.style={fill=red},
  % Style that chooses which style to apply depending on the input text
  choose/.code={
    %% Fails (error):
    \tikzset{\chooseStyle{#1}{styleA}{styleB}}
    %% Fails (error):
    % \expandafter\tikzset{\chooseStyle{#1}{styleA}{styleB}}
    %% Fails (bad style applied)
    % \ifthenelse{\equal{\chooseStyle{#1}{styleA}{styleB}}{styleA}}{\tikzset{styleA}}{\tikzset{styleB}}
  },
}


\makeatletter
\newsavebox\zx@box % Temporary box to compute height/width/depth

\NewDocumentCommand{\chooseStyle}{mmm}{%
  % #1=text,#2=empty style,#3=other style
  \savebox\zx@box{#1}%
  % Check if width is 0pt:
  \ifdimcomp{\wd\zx@box}{=}{0pt}{% Return empty style if box is empty
    #2% Empty style
  }{%
    #3 % other style
  }%
}

\makeatother

\begin{document}

\chooseStyle{}{styleA}{styleB}
\chooseStyle{abc}{styleA}{styleB}

\begin{tikzcd}
  \node[choose=]{}; % Should display a green node
\end{tikzcd}

\end{document}