Documenting data structures

[Jorge <xxopxe@...>]

Hi to everyone.

A question, what do you people use for documenting datastructures? Say, 
you program has a table that maps string to arrays of numbers, or have a 
function that receive a table with specific set of keys expected, and 
stuff like that.

Ideally, some portable/standard/intuitive option would be great, like a 
pseudocode but for data structures. Alternatively, I'm aware there are 
some data description formats for the typed variations of lua, perhaps 
some of that could be used?

Jorge