The PET platform for experimentation with hpsg processing and implementation techniques
is introduced. PET provides an extendible set of building blocks for the implementation of
efficient processors. This enables straightforward comparison of different approaches, rapid
development of new techniques and easy synthesis of known techniques. An overview of the
basic design is given and key aspects of the implementation are discussed. Early empirical
results on the three standard test sets for the LinGO grammar are given. Two improved
expansion strategies are evaluated empirically. The results of fine tuning the quick check
filtering method through empirical study are discussed as an exemplar of the proposed
experimental approach to the development and optimization of processing techniques. An
overview of the progress in processing the LinGO grammar made over a development period
of three years is given.