[developers] Structured output from ACE

[Stephan Oepen]

> The additional data in the derivation tree include, on each node:
>  - "type" : the lexical or rule type

there is an extension to UDF that allows decorating nodes (which
identify grammar entitites) with their types; look or UDX here:

  http://moin.delph-in.net/ItsdbDerivations

i expect the default derivation reader in [incr tsdb()] accepts UDX,
but i would not want the redundant information to go into actual
profiles (they are bulky enough already).  so, if you were to go down
this route, i would recommend that ACE by default output UDF when
producing [incr tsdb()] format, and that the additional pieces of UDX
be activated by a separate switch?

cheers, oe