Structure of a Lex SpecificationDefinition SectionRules SectionUser SubroutinesBEGINBugsAmbiguous LookaheadAT&T LexFlexCharacter TranslationsContext SensitivityLeft ContextRight ContextDefinitions (Substitutions)ECHOInclude Operations (Logical Nesting of Files)File Chaining with yywrap()File NestingAT&T LexFlexMKS LexAbraxas PclexPOSIX LexInput from StringsAT&T LexFlexAbraxas PclexMKS LexPOSIX Lexinput()Internal Tables (%N Declarations)lex Librarymain()Other Library RoutinesLine Numbers and yylinenoLiteral BlockMultiple Lexers in One ProgramCombined LexersMultiple LexersUsing the p FlagFaking Itoutput()Portability of Lex LexersPorting Lex SpecificationsPorting Generated C LexersLibrariesBuffer SizesCharacter SetsRegular Expression SyntaxMetacharactersPOSIX ExtensionsREJECTReturning Values from yylex()Start Statesunput()yyinput(), yyoutput(), yyunput()yylengyyless()yylex()User Code in yylex()yymore()yytextEnlarging yytextAT&T and MKS LexFlexPclexyywrap()