% BEGIN_FOLD Attributes
\yquant@langhelper@declare@attr{%
   value/.store in=\yquant@lang@attr@value,%
   after/.code={%
      \yquant@register@get@ids{#1}%
      \let\yquant@lang@attr@after=\yquant@register@get@ids@list%
   },%
   type/.store in=\yquant@lang@attr@type,%
   ancilla/.code={%
      \undef\yquant@lang@attr@input%
      \undef\yquant@lang@attr@output%
   },%
   in/.code={%
      \let\yquant@lang@attr@input=\relax%
      \undef\yquant@lang@attr@output%
   },%
   out/.code={%
      \undef\yquant@lang@attr@input%
      \let\yquant@lang@attr@output=\relax%
   },%
   inout/.code={%
      \let\yquant@lang@attr@input=\relax%
      \let\yquant@lang@attr@output=\relax%
   },%
   frameless/.code={%
      \pgfkeysalso{/yquant/operators/subcircuit/frameless}%
      \appto\yquant@attrs@remaining{,/yquant/operators/subcircuit/frameless}%
   },%
   seamless/.code={%
      \pgfkeysalso{/yquant/operators/subcircuit/seamless}%
      \appto\yquant@attrs@remaining{,/yquant/operators/subcircuit/seamless}%
   },%
   direct control/.code={%
      \let\yquant@lang@attr@directcontrol=\relax%
   },%
   indirect control/.code={%
      \undef\yquant@lang@attr@directcontrol%
   },%
   name mangling/.code={%
      \pgfkeysalso{/yquant/operators/subcircuit/name mangling={#1}}%
      \appto\yquant@attrs@remaining{,/yquant/operators/subcircuit/name mangling={#1}}%
   }%
}
\yquant@langhelper@declare@attr@global{%
   name/.store in=\yquant@lang@attr@name,%
   overlay/.code={%
      \ifstrequal{#1}{true}{%
         \yquant@lang@attr@overlay@multitrue%
         \yquant@lang@attr@overlay@heighttrue%
         \yquant@lang@attr@overlay@depthtrue%
      }{%
         \ifstrequal{#1}{false}{%
            % Why??? This is the default and should always be reset automatically!
            \yquant@lang@attr@overlay@multifalse%
            \yquant@lang@attr@overlay@heightfalse%
            \yquant@lang@attr@overlay@depthfalse%
         }{%
            \pgfqkeys{/yquant/global attrs/overlay}{#1}%
         }%
      }%
   },%
   overlay/.default=true,%
   overlay/multi/.is if=yquant@lang@attr@overlay@multi,%
   overlay/m/.forward to=/yquant/global attrs/overlay/multi,%
   overlay/height/.is if=yquant@lang@attr@overlay@height,%
   overlay/ht/.forward to=/yquant/global attrs/overlay/height,%
   overlay/h/.forward to=/yquant/global attrs/overlay/height,%
   overlay/left/.forward to=/yquant/global attrs/overlay/height,%
   overlay/l/.forward to=/yquant/global attrs/overlay/height,%
   overlay/before/.forward to=/yquant/global attrs/overlay/height,%
   overlay/bef/.forward to=/yquant/global attrs/overlay/height,%
   overlay/b/.forward to=/yquant/global attrs/overlay/height,%
   overlay/depth/.is if=yquant@lang@attr@overlay@depth,%
   overlay/dp/.forward to=/yquant/global attrs/overlay/depth,%
   overlay/d/.forward to=/yquant/global attrs/overlay/depth,%
   overlay/right/.forward to=/yquant/global attrs/overlay/depth,%
   overlay/r/.forward to=/yquant/global attrs/overlay/depth,%
   overlay/after/.forward to=/yquant/global attrs/overlay/depth,%
   overlay/aft/.forward to=/yquant/global attrs/overlay/depth,%
   overlay/a/.forward to=/yquant/global attrs/overlay/depth,%
   overlay/single/.code={\pgfkeysalso{%
      /yquant/global attrs/overlay/height={#1},%
      /yquant/global attrs/overlay/depth={#1}%
   }},%
   overlay/single/.default=true,%
   overlay/s/.forward to=/yquant/global attrs/overlay/single,%
}
\newif\ifyquant@lang@attr@overlay@multi%
\newif\ifyquant@lang@attr@overlay@height%
\newif\ifyquant@lang@attr@overlay@depth%

\protected\def\yquant@lang@reset@attrs{%
   \undef\yquant@lang@attr@value%
   \undef\yquant@lang@attr@after%
   \undef\yquant@lang@attr@type%
   \yquant@lang@reset@attrs@inputoutput%
   \let\yquant@lang@attr@name=\empty%
   \yquant@lang@attr@overlay@multifalse%
   \yquant@lang@attr@overlay@heightfalse%
   \yquant@lang@attr@overlay@depthfalse%
}

\protected\def\yquant@lang@reset@attrs@inputoutput{%
   \undef\yquant@lang@attr@input%
   \undef\yquant@lang@attr@output%
}

\protected\def\yquant@lang@reset@attrs@inputoutput@subcircuit{%
   \let\yquant@lang@attr@input=\relax%
   \let\yquant@lang@attr@output=\relax%
}
% END_FOLD

% BEGIN_FOLD Declaration of registers
\yquant@langhelper@declare@command@create{nobit}\yquant@lang@@nobit
\yquant@langhelper@setup@attrs{nobit}{}{ancilla,out}
\def\yquant@lang@@nobit#1{%
   \let\yquant@lang@create@type=\yquant@register@type@none%
   \def\yquant@lang@create@style{initial}% there is no separate style, just duplicate
   \ifdefined\yquant@lang@attr@value%
      \PackageError{yquant.sty}{Placeholder initialization must not have value}%
                   {You must not provide a description for an invisible register.}
   \else%
      \let\yquant@lang@attr@value=\empty%
   \fi%
   \yquant@lang@create@parse@name#1[;%
}

\yquant@langhelper@declare@command@create{qubit}\yquant@lang@@qubit
\yquant@langhelper@setup@attrs{qubit}{}{after,value,ancilla,in,out,inout}
\def\yquant@lang@@qubit#1{%
   \let\yquant@lang@create@type=\yquant@register@type@q%
   \def\yquant@lang@create@style{qubit}%
   \unless\ifdefined\yquant@lang@attr@value%
      \let\yquant@lang@attr@value=\yquant@config@register@default@name%
   \fi%
   \yquant@lang@create@parse@name#1[;%
}

\yquant@langhelper@declare@command@create{cbit}\yquant@lang@@cbit
\yquant@langhelper@setup@attrs{cbit}{}{after,value,ancilla,in,out,inout}
\def\yquant@lang@@cbit#1{%
   \let\yquant@lang@create@type=\yquant@register@type@c%
   \def\yquant@lang@create@style{cbit}%
   \unless\ifdefined\yquant@lang@attr@value%
      \let\yquant@lang@attr@value=\yquant@config@register@default@name%
   \fi%
   \yquant@lang@create@parse@name#1[;%
}

\yquant@langhelper@declare@command@create{qubits}\yquant@lang@@qubits
\yquant@langhelper@setup@attrs{qubits}{}{after,value,ancilla,in,out,inout}
\def\yquant@lang@@qubits#1{%
   \let\yquant@lang@create@type=\yquant@register@type@qs%
   \def\yquant@lang@create@style{qubits}%
   \unless\ifdefined\yquant@lang@attr@value%
      \let\yquant@lang@attr@value=\yquant@config@register@default@name%
   \fi%
   \yquant@lang@create@parse@name#1[;%
}

\def\yquant@lang@create@parse@name#1[#2;{%
   \ifstrempty{#2}{%
      \yquant@lang@create@do#1[1][;%
   }{%
      \yquant@lang@create@do#1[#2;%
   }%
}

\protected\def\yquant@lang@maybe@idx{}

\protected\def\yquant@lang@create@do#1[#2]#3[;{%
   % parse length
   \ifstrempty{#3}{%
      \yquant@langhelper@validate\len\count{#2}%
      \ifnum\len<1 %
         \PackageError{yquant.sty}{Invalid register length}%
                      {Valid register lengths are integers greater or equal to one.}%
      \fi%
   }{%
      \PackageError{yquant.sty}{Invalid register name}%
         {Register names must not contain `[' apart from register length indication.}%
   }%
   \edef\reg{\trim@spaces{#1}}%
   % we allow for scattering, so check whether the register already exists
   \ifcsname\yquant@prefix registerhigh@\reg\endcsname%
      \ifyquant@firsttoken+{#2}{%
         \numdef\idx{\csname\yquant@prefix registerhigh@\reg\endcsname+1}%
         \numdef\len{\len+\idx}%
      }{%
         \PackageError{yquant.sty}{Duplicate registers}%
            {Register `\reg' was already defined. Use `\reg[+#2]' with explicit plus symbol to indicate that you want to enlarge the register on purpose.}%
      }%
   \else%
      \def\idx{0}%
   \fi%
   \ifnum\len>1
      \def\regidx{\reg[\idx]}%
   \else%
      \ifnum\yquant@compat<4 %
         \let\regidx=\reg%
      \else%
         \def\regidx{\reg\vphantom[\yquant@lang@maybe@idx}%
      \fi%
      % Note: the \vphantom[ is a cheap excuse. We don't know yet whether our register will be a vector register. Currently, it is not, but it might be extended later on. But always putting the height of [ in here makes it larger than necessary. However, this should be acceptable, for unless the register contains only swaps and phases, it will be larger than the [ anyway. But this is breaking behavior, so we protect it.
   \fi%
   \numdef\yquant@circuit@operator@mintarget{\csname\yquant@prefix registers\endcsname+1}%
   % create the registers
   \begingroup%
      % if we have the after attribute, we start with a discarded wire
      \ifdefined\yquant@lang@attr@after%
         \ifdefined\yquant@lang@attr@input%
            \PackageError{yquant.sty}{An input register cannot be created with `after` attribute}{}%
         \fi%
         \let\yquant@lang@create@type=\yquant@register@type@none%
      \fi%
      \yquant@for \idx := \idx to \numexpr \len -1\relax {%
         \yquant@prepare@create\reg\idx\yquant@lang@create@type%
      }%
   \endgroup%
   % gather details about the created registers
   \letcs\yquant@circuit@operator@maxtarget{\yquant@prefix registers}%
   \numdef\yquant@circuit@operator@numtarget{\yquant@circuit@operator@maxtarget-\yquant@circuit@operator@mintarget+1}%
   \edef\yquant@circuit@operator@targets{%
      \yquant@list@range%
         \yquant@circuit@operator@mintarget%
         \yquant@circuit@operator@maxtarget%
   }%
   \let\yquant@circuit@operator@pctrls=\empty%
   \def\yquant@circuit@operator@minpctrl{2147483647}%
   \def\yquant@circuit@operator@maxpctrl{0}%
   \let\yquant@circuit@operator@numpctrl=\yquant@circuit@operator@maxpctrl%
   \let\yquant@circuit@operator@nctrls=\empty%
   \let\yquant@circuit@operator@minnctrl=\yquant@circuit@operator@minpctrl%
   \let\yquant@circuit@operator@maxnctrl=\yquant@circuit@operator@maxpctrl%
   \let\yquant@circuit@operator@numnctrl=\yquant@circuit@operator@numpctrl%
   \let\yquant@circuit@operator@minctrl=\yquant@circuit@operator@mintarget%
   \let\yquant@circuit@operator@maxctrl=\yquant@circuit@operator@maxtarget%
   % if we have the after attribute, we fake an align gate
   \ifdefined\yquant@lang@attr@after%
      \edef\jointindices{\yquant@circuit@operator@targets\yquant@lang@attr@after}%
      \yquant@circuit@align\jointindices%
      % and we also need to change the wire after the alignment
      \let\yquant@circuit@settype@to=\yquant@lang@create@type%
      \let\yquant@prepare@callback@prepare=\yquant@circuit@settype@prepare%
      \let\yquant@prepare@callback@draw=\yquant@circuit@settype%
      \expandafter\@thirdofthree%
   \else%
      \expandafter\@firstofone%
   \fi%
   % unless there is no name, no text and no after attribute, we now need an init gate
   {%
      \ifx\yquant@lang@attr@value\empty%
         \expandafter\@firstofone%
      \else%
         \expandafter\@secondoftwo%
      \fi%
   }%
   {%
      \ifx\yquant@lang@attr@name\empty%
         \expandafter\@gobble%
      \else%
         \expandafter\@firstofone%
      \fi%
   }%
   {%
      % there are no multi inits in this context
      \epreto\yquant@attrs@remaining{internal/move label, internal/setregidx={\idx}{\reg},}%
      \def\yquant@config@operator@minimum@width{0pt}%
      \unless\ifx\yquant@lang@attr@value\empty%
         % make sure to immediately remove the "clear" marker again if we have a text
         \yquant@for \i := \yquant@circuit@operator@mintarget to \yquant@circuit@operator@maxtarget {%
            \yquant@register@execclear@lastgate{\i}{init}%
         }%
      \fi%
      \expandafter\yquant@prepare%
         \expandafter{\yquant@lang@attr@value}%
         {/yquant/every label, /yquant/every initial label,%
          /yquant/every \yquant@lang@create@style\space label,%
          \ifnum\yquant@compat<2 \ifdefined\yquant@lang@attr@input /yquant/every input label\fi\fi}%
      \unless\ifx\yquant@lang@attr@name\empty%
         \ifnum\len=1 %
            \csxappto{\yquant@prefix draw}%
                     {\yquant@draw@alias{\yquant@lang@attr@name}}%
         \fi%
      \fi%
   }%
}
% END_FOLD

% BEGIN_FOLD Define own gates
% if the argument contains #2, replace it by #1 and add value as a required attribute
\protected\def\yquantdefinegate@parsearg#1#2{%
   \def\yquantdefinegate@parsearg@check##1{#2}%
   \edef\yquantdefinegate@parsearg@replaced{%
      \unexpanded\expandafter{\yquantdefinegate@parsearg@check{#1}}%
   }%
   \edef\yquantdefinegate@parsearg@compare{%
      \unexpanded\expandafter{\yquantdefinegate@parsearg@check\dummy}%
   }%
   \unless\ifx\yquantdefinegate@parsearg@replaced\yquantdefinegate@parsearg@compare%
      \preto\yquantdefinegate@requiredattrs{value,}%
   \fi%
}

\let\yquantdeclareattr=\yquant@langhelper@declare@attr

\pgfqkeys{/yquant/definegate}{%
   required attrs/.store in=\yquantdefinegate@requiredattrs,%
   optional attrs/.store in=\yquantdefinegate@optionalattrs
}

\ifnum\yquant@compat<4 %
   \protected\def\yquantdefinegate@compaterror#1{%
      \protected\def#1{%
         \PackageError{yquant.sty}{Undefined control sequence \string#1\space}%
                      {Command \string#1\space requires compat version at least 0.8.}%
      }
   }

   \protected\def\yquantdefinegate{%
      \yquantdefinegate@{\yquantdefinegate@namecheck\yquantredefinegate}\@firstofone%
   }

   \yquantdefinegate@compaterror\yquantedefinegate

   \protected\def\yquantredefinegate{%
      \yquantdefinegate@{\yquantredefinegate@namecheck\yquantdefinegate}\@firstofone%
   }

   \yquantdefinegate@compaterror\yquanteredefinegate
\else
   \protected\def\yquantdefinegate{%
      \yquantdefinegate@{\yquantdefinegate@namecheck\yquantredefinegate}\expandonce%
   }

   \protected\def\yquantedefinegate{%
      \yquantdefinegate@{\yquantdefinegate@namecheck\yquanteredefinegate}\@firstofone%
   }

   \protected\def\yquantredefinegate{%
      \yquantdefinegate@{\yquantredefinegate@namecheck\yquantdefinegate}\expandonce%
   }

   \protected\def\yquanteredefinegate{%
      \yquantdefinegate@{\yquantredefinegate@namecheck\yquantedefinegate}\@firstofone%
   }
\fi

\protected\def\yquantdefinegate@namecheck#1#2{%
   \ifcsname yquant@lang@#2\endcsname%
      \PackageError{yquant.sty}{Gate redefined}%
                   {The gate `#2' already exists. Use \string#1\space if you really want to redefine it.}%
   \fi%
}

\protected\def\yquantredefinegate@namecheck#1#2{%
   \unless\ifcsname yquant@lang@#2\endcsname%
      \PackageError{yquant.sty}{Unknown gate redefined}%
                   {The gate `#2' is unknown and cannot be redefined. Use \string#1\space to define it.}%
   \fi%
}

\protected\def\yquantdefinegate@#1#2{%
   \@ifnextchar[{\yquantdefinegate@i{#1}{#2}}
                {\yquantdefinegate@i{#1}{#2}[]}%
}

\protected\def\yquantdefinegate@i#1#2[#3]#4{%
   % #1: namecheck macro
   % #2: what to do with expansion
   % #3: attributes
   % #4: gate name
   #1{#4}%
   \yquant@begingroup%
      \let\yquantdefinegate@requiredattrs=\empty%
      \let\yquantdefinegate@optionalattrs=\empty%
      \pgfqkeys{/yquant/definegate}{#3}%
      \@ifnextchar[{\yquantdefinegate@ii{#2}{#4}}%
                   {\yquantdefinegate@ii{#2}{#4}[/yquant/operators/every custom gate]}%
}

\protected\long\def\yquantdefinegate@ii#1#2[#3]#4{%
   % #1: what to do with expansion
   % #2: gate name
   % #3: style
   % #4: content
      \yquant@prepare@ifs@set%
      % usually, we will not be in a tikzpicture here, so all the commands that abbreviate some path operation are undefined!
      \tikz@installcommands%
      % While we want the content to be expanded, protect the most likely TikZ commands - the same ones that we usually substitute in \yquant@env@substikz.
      \let\path=\yquant@protectedempty%
      \let\scoped=\path%
      \let\scope=\path%
      \let\endscope=\path%
      \let\stopscope=\path%
      \ifx#1\@firstofone%
         \yquantdefinegate@parsearg{\noexpand\yquantdefinegate@attr@value}{#4}%
      \else%
         \yquantdefinegate@parsearg\yquantdefinegate@attr@value{#4}%
      \fi%
      \protected@edef\yquantdefinegate@do{%
         \yquant@endgroup%
         \noexpand\pgfkeys{/yquant/operators/every #2/.code={%
            \yquant@config@operator@subcircuit@mangling@set{%
               \yquant@config@operator@subcircuit@mangling%
            }%
            \noexpand\pgfkeysalso{\unexpanded{#3}}%
         }}%
         \yquant@langhelper@declare@command%
            {#2}%
            \yquant@register@get@multiaslist%
            {%
               \let\noexpand\yquant@circuit@subcircuit@content=\expandafter\noexpand\csname yquant@lang@@#2\endcsname%
               % the value attribute will be reset for the subcircuit, so we'll preserve it
               \let\noexpand\yquantdefinegate@attr@value=\noexpand\yquant@lang@attr@value%
               \yquant@prepare@subcircuit{/yquant/operators/every #2}%
            }%
         % This does not clear the attributes for redefines, but makes at least sure nothing is marked as required that should not be.
         \yquant@langhelper@setup@attrs{#2}{\yquantdefinegate@requiredattrs}%
                                           {\yquantdefinegate@optionalattrs}%
         % Now define the gate's content as a macro
         \def\expandafter\noexpand\csname yquant@lang@@#2\endcsname{%
            #1{\yquantdefinegate@parsearg@replaced}%
         }%
      }%
   \yquantdefinegate@do%
}

\ifnum\yquant@compat<4 %
   \protected\def\yquantdefinebox{%
      \yquantdefinebox@{\yquantdefinegate@namecheck\yquantredefinebox}{}\@firstofone%
   }

   \yquantdefinegate@compaterror\yquantedefinebox

   \protected\def\yquantredefinebox{%
      \yquantdefinebox@{\yquantredefinegate@namecheck\yquantdefinebox}{}\@firstofone%
   }

   \yquantdefinegate@compaterror\yquanteredefinebox

   \protected\def\yquantdefinemultibox{%
      \yquantdefinebox@{\yquantdefinegate@namecheck\yquantredefinemultibox}%
                       \yquant@register@get@allowmultitrue\@firstofone%
   }

   \yquantdefinegate@compaterror\yquantedefinemultibox

   \protected\def\yquantredefinemultibox{%
      \yquantdefinebox@{\yquantredefinegate@namecheck\yquantdefinemultibox}%
                       \yquant@register@get@allowmultitrue\@firstofone%
   }

   \yquantdefinegate@compaterror\yquanteredefinemultibox
\else
   \protected\def\yquantdefinebox{%
      \yquantdefinebox@{\yquantdefinegate@namecheck\yquantredefinebox}{}\expandonce%
   }

   \protected\def\yquantedefinebox{%
      \yquantdefinebox@{\yquantdefinegate@namecheck\yquanteredefinebox}{}\@firstofone%
   }

   \protected\def\yquantredefinebox{%
      \yquantdefinebox@{\yquantredefinegate@namecheck\yquantdefinebox}{}\expandonce%
   }

   \protected\def\yquanteredefinebox{%
      \yquantdefinebox@{\yquantredefinegate@namecheck\yquantedefinebox}{}\@firstofone%
   }

   \protected\def\yquantdefinemultibox{%
      \yquantdefinebox@{\yquantdefinegate@namecheck\yquantredefinemultibox}%
                       \yquant@register@get@allowmultitrue\expandonce%
   }

   \protected\def\yquantedefinemultibox{%
      \yquantdefinebox@{\yquantdefinegate@namecheck\yquanteredefinemultibox}%
                       \yquant@register@get@allowmultitrue\@firstofone%
   }

   \protected\def\yquantredefinemultibox{%
      \yquantdefinebox@{\yquantredefinegate@namecheck\yquantdefinemultibox}%
                       \yquant@register@get@allowmultitrue\expandonce%
   }

   \protected\def\yquanteredefinemultibox{%
      \yquantdefinebox@{\yquantredefinegate@namecheck\yquantedefinemultibox}%
                       \yquant@register@get@allowmultitrue\@firstofone%
   }
\fi

\protected\def\yquantdefinebox@#1#2#3{%
   \@ifnextchar[{\yquantdefinebox@i{#1}{#2}{#3}}%
                {\yquantdefinebox@i{#1}{#2}{#3}[]}%
}

\protected\def\yquantdefinebox@i#1#2#3[#4]#5{%
   % #1: namecheck macro
   % #2: allow multi
   % #3: what to do with expansion
   % #4: attributes
   % #5: gate name
   #1{#5}%
   \yquant@begingroup%
      \let\yquantdefinegate@requiredattrs=\empty%
      \let\yquantdefinegate@optionalattrs=\empty%
      \pgfqkeys{/yquant/definegate}{#4}%
      \@ifnextchar[{\yquantdefinebox@ii{#2}{#3}{#5}}%
                   {\yquantdefinebox@ii{#2}{#3}{#5}[/yquant/operators/every rectangular box]}%
}

\protected\long\def\yquantdefinebox@ii#1#2#3[#4]#5{%
   % #1: allow multi
   % #2: what to do with expansion
   % #3: gate name
   % #4: style
   % #5: content
      \yquant@prepare@ifs@set%
      \ifx#2\@firstofone%
         \yquantdefinegate@parsearg{\noexpand\yquant@lang@attr@value}{#5}%
      \else%
         \yquantdefinegate@parsearg\yquant@lang@attr@value{#5}%
      \fi%
      \protected@edef\yquantdefinebox@do{%
         \yquant@endgroup%
         \unexpanded{\pgfkeys{/yquant/operators/every #3/.style={#4}}}%
         \yquant@langhelper@declare@command%
            {#3}%
            {\unexpanded{#1}}%
            {%
               \yquant@prepare{#2{\yquantdefinegate@parsearg@replaced}}%
                              {/yquant/operators/every #3}%
            }%
         \yquant@langhelper@setup@attrs{#3}{\yquantdefinegate@requiredattrs}%
                                           {\yquantdefinegate@optionalattrs}%
      }%
   \yquantdefinebox@do%
}
% END_FOLD

% BEGIN_FOLD Box registers
% all-purpose box with arbitrary text
\yquant@langhelper@declare@command%
   {box}%
   \yquant@register@get@allowmultitrue%
   {%
      \expandafter\yquant@prepare%
         \expandafter{\yquant@lang@attr@value}%
         {/yquant/operators/every box}%
   }
\yquant@langhelper@setup@attrs{box}{value}{}

\yquant@langhelper@declare@command%
   {text}%
   \yquant@register@get@allowmultitrue%
   {%
      \expandafter\yquant@prepare%
         \expandafter{\yquant@lang@attr@value}%
         {/yquant/operators/every text}%
   }
\yquant@langhelper@setup@attrs{text}{value}{}

% Hadamard
\yquantdefinebox{h}{$H$}

% Pauli X (or NOT)
\yquantdefinebox{x}[/yquant/operators/every pauli]{$X$}

% Pauli Y
\yquantdefinebox{y}[/yquant/operators/every pauli]{$Y$}

% Pauli Z
\yquantdefinebox{z}[/yquant/operators/every pauli]{$Z$}

% sub-circuit: This is a nested circuit.
\yquant@langhelper@declare@command%
   {subcircuit}%
   \yquant@register@get@multiaslist%
   {%
      \let\yquant@circuit@subcircuit@content=\yquant@lang@attr@value%
      \yquant@prepare@subcircuit{/yquant/operators/every subcircuit}%
   }
\yquant@langhelper@setup@attrs{subcircuit}{value}{frameless,seamless,name mangling}
% END_FOLD

% BEGIN_FOLD other geometric shapes
% phase
\yquant@langhelper@declare@command%
   {phase}%
   {}%
   {%
      \edef\cmd{%
         \yquant@prepare%
            {}%
            {/yquant/operators/every phase, label={\unexpanded\expandafter{\yquant@lang@attr@value}}}%
      }%
      \cmd%
   }
\yquant@langhelper@setup@attrs{phase}{value}{}%

% two-qubit controlled x (symmetric notation)
\yquant@langhelper@declare@command%
   {xx}%
   \yquant@register@get@multiassingle%
   {%
      \yquant@prepare%
         {}%
         {/yquant/operators/every xx}%
   }
\yquant@langhelper@setup@attrs{xx}{}{}

% two-qubit controlled phase (symmetric notation)
\yquant@langhelper@declare@command@uncontrolled%
   {zz}%
   \yquant@register@get@multiassingle%
   {%
      \yquant@prepare%
         {}%
         {/yquant/operators/every zz}%
   }
\yquant@langhelper@setup@attrs{zz}{}{}

% slash (pseudo-operator, alternative indication for a bundle)
\yquant@langhelper@declare@command@uncontrolled%
   {slash}%
   {}%
   {%
      % temporarily squeeze most into the separation
      \pgfkeys{%
         /yquant/operator/minimum width=0pt,%
      }%
      \preto\yquant@attrs@remaining{internal/squeeze slash,}%
      \yquant@prepare%
         {}%
         {/yquant/operators/every slash}%
   }
\yquant@langhelper@setup@attrs{slash}{}{}

% swap
\yquant@langhelper@declare@command%
   {swap}%
   \yquant@register@get@multiassingle
   {%
      \yquant@prepare%
         {}%
         {/yquant/operators/every swap}%
   }
\yquant@langhelper@setup@attrs{swap}{}{}

% iswap
\yquant@langhelper@declare@command%
   {iswap}%
   \yquant@register@get@multiassingle
   {%
      \yquant@prepare%
         {}%
         {/yquant/operators/every iswap}%
   }
\yquant@langhelper@setup@attrs{iswap}{}{}

% not
\yquant@langhelper@declare@command%
   {not}%
   {}%
   {%
      \yquant@prepare%
         {}%
         {/yquant/operators/every not}%
   }
\yquant@langhelper@setup@attrs{not}{}{}
% alias to cnot
\yquant@langhelper@declare@command@alias{cnot}{not}
\yquant@langhelper@setup@attrs{cnot}{}{}

% measure
\yquant@langhelper@declare@command@uncontrolled%
   {measure}%
   \yquant@register@get@allowmultitrue%
   {%
      \ifdefined\yquant@lang@attr@type%
         \yquant@register@type@fromstring\yquant@lang@attr@type\yquant@circuit@settype@to%
      \else%
         \let\yquant@circuit@settype@to=\yquant@register@type@c%
      \fi%
      \let\yquant@prepare@callback@prepare=\yquant@circuit@settype@prepare%
      \let\yquant@prepare@callback@draw=\yquant@circuit@settype%
      \unless\ifcsname yquant@lang@attr@value\endcsname%
         \let\yquant@lang@attr@value=\empty%
      \fi%
      \ifdefined\yquant@lang@attr@directcontrol%
         % direct control means that we must defer this operator until the next that has this/these targets as positive controls.
         \expandafter\yquant@prepare@injection%
            \expandafter{\yquant@lang@attr@value}%
            {/yquant/operators/every measure}%
      \else%
         \expandafter\yquant@prepare%
            \expandafter{\yquant@lang@attr@value}%
            {/yquant/operators/every measure}%
      \fi%
   }
\yquant@langhelper@setup@attrs{measure}{}{value,type,direct control,indirect control}

% measure (dmeter)
\yquant@langhelper@declare@command@uncontrolled%
   {dmeter}%
   \yquant@register@get@allowmultitrue%
   {%
      \ifdefined\yquant@lang@attr@type%
         \yquant@register@type@fromstring\yquant@lang@attr@type\yquant@circuit@settype@to%
      \else%
         \let\yquant@circuit@settype@to=\yquant@register@type@c%
      \fi%
      \let\yquant@prepare@callback@prepare=\yquant@circuit@settype@prepare%
      \let\yquant@prepare@callback@draw=\yquant@circuit@settype%
      \unless\ifcsname yquant@lang@attr@value\endcsname%
         \let\yquant@lang@attr@value=\empty%
      \fi%
      \expandafter\yquant@prepare%
         \expandafter{\yquant@lang@attr@value}%
         {/yquant/operators/every dmeter}%
   }
\yquant@langhelper@setup@attrs{dmeter}{}{value,type}
% END_FOLD

% BEGIN_FOLD miscellaneous
\yquant@langhelper@declare@command@uncontrolled%
   {barrier}%
   \yquant@register@get@allowmultitrue%
   {%
      \yquant@prepare%
         {}%
         {/yquant/operators/every barrier}%
   }%
\yquant@langhelper@setup@attrs{barrier}{}{}

\yquant@langhelper@declare@command@uncontrolled%
   {correlate}%
   {%
      % do not call \yquant@register@get@multiassingle, we do not want to install a different multi line style!
      \yquant@register@get@allowmultitrue%
      \let\yquant@register@multi@splitparts=\yquant@register@multi@splitparts@sepall%
   }{%
      \yquant@prepare%
         {}%
         {/yquant/operators/every wave}%
   }
\yquant@langhelper@setup@attrs{correlate}{}{}

\yquant@langhelper@declare@command@uncontrolled%
   {align}%
   {}%
   {%
      \yquant@circuit@align\yquant@circuit@operator@targets%
   }
\yquant@langhelper@setup@attrs{align}{}{}

\yquant@langhelper@declare@command@uncontrolled%
   {hspace}%
   {%
      \yquant@langhelper@validate\amount\dimen\yquant@lang@attr@value%
   }{%
      \yquant@circuit@hspace\yquant@circuit@operator@targets\amount%
   }
\yquant@langhelper@setup@attrs{hspace}{value}{}

\yquant@langhelper@declare@command%
   {discard}%
   {}%
   {%
      \let\yquant@circuit@settype@to=\yquant@register@type@none%
      \ifyquant@circuit@operator@hasControls%
         \epreto\yquant@attrs@remaining{internal/corner={\yquant@orientation@plus}{\yquant@circuit@operator@targets}{\yquant@circuit@operator@minctrl}{\yquant@circuit@operator@maxctrl},}%
         \let\yquant@prepare@callback@prepare=\yquant@circuit@settype@prepare%
         \let\yquant@prepare@callback@draw=\yquant@circuit@settype@beforenobit%
         \yquant@prepare%
            {}%
            {shape=yquant-nothing}%
      \else%
         \yquant@circuit@actonwires%
            \yquant@circuit@settype@prepare%
            \yquant@circuit@settype%
            \yquant@circuit@operator@targets%
            {}%
      \fi%
   }
\yquant@langhelper@setup@attrs{discard}{}{}

\yquant@langhelper@declare@command%
   {init}%
   {%
      \yquant@register@get@allowmultitrue%
      \let\yquant@config@register@default@lazyname=\empty%
      % we will count how many registers contain the "clean" flag, and only if this is equal to the number of targets, we apply the shift.
      \count8=0 %
   }%
   {%
      \ifdefined\yquant@lang@attr@type%
         \yquant@register@type@fromstring\yquant@lang@attr@type\yquant@circuit@settype@to%
      \else%
         % We don't know which type is desired. Scan all target registers and use the first wire that is available as a type.
         \let\yquant@circuit@settype@to=\yquant@register@type@none%
         \forlistloop\yquant@lang@@init@loop\yquant@circuit@operator@targets%
         \ifx\yquant@circuit@settype@to\yquant@register@type@none%
            % now we don't have a clue; assume it's a qubit
            \let\yquant@circuit@settype@to=\yquant@register@type@q%
         \fi%
         \edef\yquant@lang@attr@type{%
            \yquant@register@type@tostring\yquant@circuit@settype@to%
         }%
      \fi%
      \unless\ifdefined\yquant@lang@attr@value%
         \let\yquant@lang@attr@value=\empty%
      \fi%
      \let\yquant@prepare@callback@prepare=\yquant@circuit@settype@prepare%
      \ifyquant@circuit@operator@hasControls%
         \epreto\yquant@attrs@remaining{internal/corner={\yquant@orientation@minus}{\yquant@circuit@operator@targets}{\yquant@circuit@operator@minctrl}{\yquant@circuit@operator@maxctrl},}%
         \let\yquant@prepare@callback@draw=\yquant@circuit@settype@afternobit%
         \count8=0 % never apply the shift if we have controls
      \else%
         \let\yquant@prepare@callback@draw=\yquant@circuit@settype%
      \fi%
      \let\yquant@prepare@multi=\yquant@prepare@multiinit%
      \ifnum\count8=\numexpr\yquant@circuit@operator@maxctrl-\yquant@circuit@operator@minctrl+1\relax%
         \def\yquant@config@operator@minimum@width{0pt}%
         \preto\yquant@attrs@remaining{internal/move label,}%
         \edef\cmd{%
            \yquant@prepare%
               {\unexpanded\expandafter{\yquant@lang@attr@value}}%
               {/yquant/every label, /yquant/every initial label,%
                /yquant/every \yquant@lang@attr@type\space label}%
         }%
      \else%
         \edef\cmd{%
            \yquant@prepare%
               {\unexpanded\expandafter{\yquant@lang@attr@value}}%
               {/yquant/every label, /yquant/every \yquant@lang@attr@type\space label}%
         }%
      \fi%
      \cmd%
   }
\yquant@langhelper@setup@attrs{init}{}{type,value}

\protected\def\yquant@lang@@init@loop#1{%
   \ifyquant@firsttoken\yquant@register@multi{#1}{%
      \let\yquant@register@multi@contiguous=\yquant@lang@@init@multi@@extract%
      \@fifthoffive#1%
      % we should reset multi@contiguous to the original command; but this is really just a placeholder. As long as it is \protected, everything is fine.
   }{%
      \edef\yquant@circuit@settype@to{\yquant@register@get@type{#1}}%
   }%
   \unless\ifx\yquant@circuit@settype@to\yquant@register@type@none%
      \expandafter\listbreak%
   \fi%
}

\protected\def\yquant@lang@@init@multi@@extract#1#2#3{%
   \yquant@for \yquant@i := #1 to #2 {%
      \edef\yquant@circuit@settype@to{\yquant@register@get@type\yquant@i}%
      \unless\ifx\yquant@circuit@settype@to\yquant@register@type@none%
         \expandafter\yquant@for@break%
      \fi%
   }%
}

\yquant@langhelper@declare@command@uncontrolled%
   {output}%
   \yquant@register@get@allowmultitrue%
   \yquant@circuit@output%
\yquant@langhelper@setup@attrs{output}{value}{}

\yquant@langhelper@declare@command@uncontrolled%
   {inspect}%
   \yquant@register@get@allowmultitrue%
   {%
      \expandafter\yquant@prepare%
         \expandafter{\yquant@lang@attr@value}%
         {/yquant/operators/every inspect}%
   }
\yquant@langhelper@setup@attrs{inspect}{value}{}

\yquant@langhelper@declare@command@uncontrolled%
   {settype}%
   {}%
   {%
      \yquant@register@type@fromstring\yquant@lang@attr@value\yquant@circuit@settype@to%
      \yquant@circuit@actonwires%
         \yquant@circuit@settype@prepare%
         \yquant@circuit@settype%
         \yquant@circuit@operator@targets%
         {}%
   }
\yquant@langhelper@setup@attrs{settype}{value}{}

\ifnum\yquant@compat<2 %
   \def\yquant@lang@setwire{%
      \PackageWarning{yquant.sty}{`setwire' gate is deprecated as of yquant 0.1.2. Use `settype' instead.}%
      \yquant@lang@settype%
   }
   \yquant@langhelper@setup@attrs{setwire}{value}{}
\fi

\yquant@langhelper@declare@command@uncontrolled%
   {setstyle}%
   {}%
   {%
      \yquant@circuit@actonwires%
         \@gobbletwo%
         \yquant@circuit@setstyle%
         \yquant@circuit@operator@targets%
         {{\yquant@lang@attr@value}}%
   }
\yquant@langhelper@setup@attrs{setstyle}{value}{}

\yquant@langhelper@declare@command@uncontrolled%
   {addstyle}%
   {}%
   {%
      \yquant@circuit@actonwires%
         \@gobbletwo%
         \yquant@circuit@addstyle%
         \yquant@circuit@operator@targets%
         {{\yquant@lang@attr@value}}%
   }
\yquant@langhelper@setup@attrs{addstyle}{value}{}
% END_FOLD