Bison table compression algorithm

[Satya]

hi,
I was reading the original paper about Bison - "Static Semantics and
Compiler Error Recovery" by Robert Paul Corbett, and it says Bison's table
organization is based on a technique proposed by Ziegler and described in
Tarjan and Yao in [TY78] ("Storing a Sparse Table");

My question is this: does Bison still follow that scheme? I wouldn't want to
dive into this paper ([TY78]) if  you have changed the compression scheme
during the course of Bison development history.

Also, is there is a simpler explanation of the rationale behind the tables
being organized in that way (specific to Bison)? I'd want to read about
that. Thanks!!

-- satya