Access pgfkeys outside environment

Question

I find that the value of a key defined by \pgfkeys inside an environment can not be invoked outside this environment.

In the following example, I want to typeset the value of the key aaa outside the environment minipage and fail.

How to make this kind of keys be "seen" outside environment?

Example:

\documentclass{article}
\usepackage{tikz}
\begin{document}

\begin{minipage}{1.0\linewidth}
  \pgfkeys{aaa/.initial=aaa,bbb/.initial=bbb}
  Inside minipage, the value of the key "aaa" is \pgfkeysvalueof{/aaa}
\end{minipage}
Outside minipage, the value of the key "aaa" is |\pgfkeysvalueof{/aaa}|

\end{document}

Answer 1

Since the other answer and comments explain why your code behaves the way it does, here's a .ginitial handler that is global.

That means that both the initialization aaa/.ginitial = aaa as well as just assigning a new value via aaa = AAA will be global.

However, the handlers .add, .prefix, .append, .get and .link will not change the value globally.
(We'll need .gadd, .gprefix, … for that.)

In the code below, the key /bbb remains local.

Code

\documentclass{article}
\usepackage{tikz}

\makeatletter
\long\def\pgfkeysgdef#1#2{%
  \long\def\pgfkeys@temp##1\pgfeov{#2}%
  \pgfkeysglet{#1/.@cmd}{\pgfkeys@temp}%
  \pgfkeyssetgvalue{#1/.@body}{#2}%
}
\long\def\pgfkeysglet#1#2{%
  \expandafter\global\expandafter\let\csname pgfk@#1\endcsname#2%
}
\long\def\pgfkeyssetgvalue#1#2{%
  \pgfkeys@temptoks{#2}\expandafter\xdef\csname pgfk@#1\endcsname{\the\pgfkeys@temptoks}%
}
\pgfkeys{
  /handlers/.ginitial/.code=%
    \edef\pgfkeys@temp{% \pgfkeysgdef is basically /.gcode
      \noexpand\pgfkeysgdef{\pgfkeyscurrentpath}%
        {\noexpand\pgfkeyssetgvalue{\pgfkeyscurrentpath}{####1}}}%
    \pgfkeys@temp
    \pgfkeyssetgvalue{\pgfkeyscurrentpath}{#1}%
}
\makeatother
\begin{document}

\noindent
\begin{minipage}{1.0\linewidth}
\pgfkeys{aaa/.ginitial = aaa, bbb/.initial = bbb, aaa = AAA}
Inside minipage, the values of the keys --/aaa--/bbb-- are --\pgfkeysvalueof{/aaa}--\pgfkeysvalueof{/bbb}--
\end{minipage}
Outside minipage, the values of the key --/aaa--/bbb-- are --\pgfkeysvalueof{/aaa}--\pgfkeysvalueof{/bbb}--
\end{document}

Output

Answer 2

Due to scoping, the keys you set inside the minipage are only defined inside this environment. Therefore, you would need to define the key outside of the environment or define it gobally somehow.

You could apply the approach in this answer and create a global version of the \pgfkeys macro. However, this approach is probably risky because everything \pgfkeys does internally will be global. This may lead to unintended results in certain cases and break other code (thanks to Skillmon and David Carlisle for pointing to this).

For very simple assignments, you could maybe also use \global\pgfkeyslet, but using this approach, things like .initial would not be applicable. Also, the same warning as above applies here. So, do not use this if you plan to have others use your code!

I'd recommend, therefore, to restructure the logic of your document and define the keys outside of the environment.

\documentclass{article}
\usepackage{tikz}

%%% not recoomended!
\newcommand\gpgfkeys[1]{%
\begingroup%
 \globaldefs=1\relax%
 \pgfkeys{#1}%
\endgroup%
}
%%%

\begin{document}

\pgfkeys{aaa/.initial=aaa}

\noindent
\begin{minipage}{1.0\linewidth}
  
  \def\mybbbkey{bbb}                   %%%
  \global\pgfkeyslet{/bbb}{\mybbbkey}  %%% 
                                       %%%
  \gpgfkeys{ccc/.initial=ccc}          %%% not recommended!
  
  Inside minipage, the value of the key "aaa" is \pgfkeysvalueof{/aaa} \\
  Inside minipage, the value of the key "aaa" is \pgfkeysvalueof{/bbb} \\
  Inside minipage, the value of the key "ccc" is \pgfkeysvalueof{/ccc}
\end{minipage}

\bigskip

\noindent
Outside minipage, the value of the key "aaa" is ---\pgfkeysvalueof{/aaa}--- \\
Outside minipage, the value of the key "bbb" is ---\pgfkeysvalueof{/bbb}--- \\
Outside minipage, the value of the key "ccc" is ---\pgfkeysvalueof{/ccc}---

\end{document}