Styling controls individually

[tigerjack]

Is your feature request related to a problem? Please describe.
At the moment, I can only style the whole operator or all the controls at once, but not the single controls.

Describe the solution you'd like
I would like to style each control (i.e., the dots) of a multi-controlled gate individually.

Describe alternatives you've considered
I tried to overcome the limitations using the usual begin/end{scope}, but it gets complicated and difficult to generalize.

Additional context
Using the code below

\documentclass[tikz]{standalone}
\usepackage{./yquant}
\usetikzlibrary{backgrounds,fit}
\begin{document}
\begin{tikzpicture}
  \begin{yquant}
    qubit {$q_\idx$} q[4];
    [this control/.append style={fill=orange}] 
    cnot q[3] | q[0], q[1], q[2];
    %
    [global attrs/name/.expanded={mcnot}]
    cnot q[3]| q[0], q[1], q[2];
  \end{yquant}
  \begin{scope}[on background layer, maximum width=.5pt,  every node/.style={draw,dotted}]
    \node[circle, red, fit=(mcnot-p1)] {};
    \node[circle, blue, fit=(mcnot-p2)] {};
  \end{scope}
\end{tikzpicture}
\end{document}

I obtained something like this, which is far from optimal

[projekter]

There is no "intrinsic" support for this, and there are only styling keys that address all gates, positive, or negative controls.
However, it is not too hard to fake this: As always, yquant defines the \idx macro before applying every style to the control. This macro holds the current visual index within the group (so, it iterates from 0 to the number of gates -1; from 0 to the number of positive control -1; and also negative controls). So you could simply define a conditional style like this:

\documentclass[tikz]{standalone}
\usepackage[compat=0.6]{yquant}
\begin{document}
   \begin{tikzpicture}
     \begin{yquant}
       qubit {$q_\idx$} q[4];
       [this control/.append style={fill=orange}]
       cnot q[3] | q[0], q[1], q[2];
       %
       [this control/.code={\unexpanded{%
         \ifcase\idx\relax%
            \pgfkeysalso{fill=red}%
         \or%
            \pgfkeysalso{fill=blue}%
         \else%
            \pgfkeysalso{fill=green}%
         \fi%
       }}]
       cnot q[3]| q[0], q[1], q[2];
     \end{yquant}
   \end{tikzpicture}
\end{document}

Of course, you can use any kind of style that you like. If you use this more often, it might be worth defining a custom style that does this job for you.

[tigerjack]

Excellent! Thank you @projekter