How can I draw annotated braces over and under math expressions?

Question

What LaTeX markup would one have to write to produce a result similar to the image below?

Please excuse my Paint-and-mouse drawing skills. :-)

Answer 1

amsmath's \text can help to obtain the correct size of superscript/subscript fonts in math mode, while the bracing it possible using the traditional \overbrace/\underbrace:

\documentclass{article}
\usepackage{amsmath}% http://ctan.org/pkg/amsmath
\begin{document}
$\overbrace{a\rightarrow\underbrace{(b\rightarrow c)}_{\text{bar}}}^{\text{foo}}$
\end{document}

For other symbols (like arrows), see the Comprehensive LaTeX Symbol List.

Answer 2

While Werner's solution is compact and precise, this one shows other possibilities.

\documentclass{article}
\usepackage{amsmath}
\begin{document}
  \[
  \overset{\text{foo}}{\overbrace{a\rightarrow \underset{\text{bar}}{\underbrace{(b \rightarrow c)}}}}
  \]
\end{document}

However, I would go Werner's way if I have to do this :-). (This answer is for having some fun).