The CMSSW String Cut Parser in FSA - uwcms/FinalStateAnalysis GitHub Wiki

FSA uses quite extensively the CMSSW String Expression parser, which is a tool that uses run-time object type information (provided by root:Reflex) to allow users to access object methods from configuration files.

Some documentation is available at https://twiki.cern.ch/twiki/bin/view/CMSPublic/SWGuidePhysicsCutParser

Also, here is an informative presentation about the expression parser: http://iopscience.iop.org/1742-6596/219/3/032050/pdf/1742-6596_219_3_032050.pdf