VRQ is modular verilog parser that supports plugin tools to process verilog. Plugin tools are created as independent DLLs. The tools to be invoked are specified on the command line. Multiple tools may be invoke in a pipeline fashion within a single execution of vrq. A few plugin tools are natively compiled into vrq, others are supplied as separate executables. Vrq is pretty close to fully compliant with the verilog 2005 specification, however not all tools support all constructs.
VRQ was written over 10 years ago as part of my design and verification consulting business. Over the years its been generalized to be a generic front end parser with plugin backend customizable tools. I've choosen to release it as Open Source Software to others may benefit from it as well. It has been used in multiple startups and Fortune 500 companies to develop ASICs and full custom components. In particular the Xprop Tool is one of it's most unique features as when it is used properly it can greatly reduce the need for gate level simulation.