Is there a package in either PSTricks or Tikz to draw the following diagram?

I took the following figure from JSON official site.

Is there a package to do it easily?

Anyway, what is the name of this diagram?

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If it had arrows, I'd say it's a deterministic finite state automaton. –  TH. Mar 24 '11 at 3:09
@TH If I had to guess, I'd say that the arrows are implied and it is a DFA, albeit an "artistic" representation of one. –  Aaron Mar 24 '11 at 3:38
TiKZ chains library. See the fourth tutorial in the TikZ manual. –  Caramdir Mar 24 '11 at 4:26
@Aaron: As per Herbert's answer, it appears that these syntax diagrams are supposed to be for CFGs, so I guess they aren't DFAs (although the language for this one is clearly regular). –  TH. Mar 24 '11 at 14:24

that are so-called railroad diagrams for the syntax and can be set with simple nodes and loops:

\documentclass{article}
\usepackage{pst-node}
\def\CBox#1{\pscirclebox[fillcolor=green!20,fillstyle=solid]{\bfseries#1}}
\def\PBox#1{\psframebox[fillcolor=green!20,fillstyle=solid]{\bfseries\tabular{c}#1\endtabular}}
\begin{document}

\begin{pspicture}(0,-5)(13,1)
\psset{linewidth=1.5pt,linearc=0.3}\psline{|-|}(13,0)
\psforeach{\iA}{0,1,..,13}{\pnode(\iA,0){O\iA}}
\ncloop[angleB=180,loopsize=-1]{O0}{O2}\ncput{\CBox{--}}
\rput(3,0){\CBox{0}}
\ncloop[angleB=180,loopsize=-1.75]{O2}{O6}\ncput[npos=2.3]{\PBox{digit\\1-9}}
\rput(5.5,-2.5){\rnode{A}{\PBox{digit}}}\ncloop[angleB=180,loopsize=0.75]{A}{A}
\ncloop[angleB=180,loopsize=0.75]{O6}{O9}
\end{pspicture}

\end{document}


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No package but a tutorial: Diagrams as Simple Graphs in the pgfmanual page 60. You only need to change (modify) some styles

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