TikZ: Draw a partially filled text node, i.e. a progress bar with text inside

Question

I would like to draw a node around a one-line text, with only the left part filled. The size of that 'left part' would be specified by some fraction. In effect, this would be a progress bar with text inside.

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

 \draw (0, 0) node[draw, fill = green!10, fill fraction = .7] {Some
 text};

 \end{tikzpicture}
 \end{document}

Of course my fictitious option 'fill fraction', which should say that only the leftmost 70% should be filled, gets ignored.

Answer 1

It is so cruel that TikZ ignored you, I had to do something about it. ;-)

\documentclass{article} 
\usepackage{tikz}
\usetikzlibrary{calc} 
\begin{document}
 \begin{tikzpicture}[fill fraction/.style n args={2}{path picture={
 \fill[#1] (path picture bounding box.south west) rectangle
 ($(path picture bounding box.north west)!#2!(path picture bounding box.north
 east)$);}}]

 \draw (0, 0) node[draw, fill fraction={green!10}{0.7}] {Some
 text};
 \draw (4, 0) node[circle,draw, fill fraction={green!10}{0.7}] {Some
 other text};
 \end{tikzpicture}
\end{document}