Where to look up argument for a function in TikZ?

Question

For instance,

(q_5)   edge    [loop above]        node {a}            (q_5)

This is Automaton package, the one I want to look up is [loop above], I want to know what other options can I put in there. I know there are:

• [bend left]
• [bend right]
• [loop above]
• [loop below]

I checked at http://www.texample.net/tikz/examples/state-machine/ but all I found were just examples :(. There are no manual or reference to look up optional arguments..., I guess there must be one, but somehow I couldn't find them. So where can I find these documents?

Answer 1

The automata package is part of the TikZ/PGF system and is documented in the PGF manual (Section 24 of the manual for PGF2.10).

The loops are actually provided as part of the to library which is documented in Section 51.4 of that manual.