Chapter1,ARegularExpressionMatcher,byBrianKernighan,showshowdeepinsightintoalanguageandaproblemcanleadtoaconciseandelegantsolution.Chapter2,Subversion’sDeltaEditor:InterfaceAsOntology,byKarlFogel,startswithawellchosenabstractionanddemonstratesitsunifyingeffectsonthesystem’sfurtherd