Examples of fri.patterns.interpreter.parsergenerator.lexer.LexerBuilder

• fri.patterns.interpreter.parsergenerator.lexer.LexerBuilder
  g! Nevertheless you need not to care about the names silently imported from StandardLexerRules, they will not reduce the parser syntax namespace, only the toplevel rules will.

  The syntax may contain (case-sensitive) these nonterminals:

  • token
  • ignored

  These are lexer-reserved identifiers and can be used to mark top level lexer rules (tokens). When token is used, the builder does not try to recognize any rule as lexer rule, so this must be good modeled. Be careful: you can read away comments only by using ignored. But you can define ignored without token, then nevertheless the builder tries to recognize lexer rules.
  When the token marker is not used, the builder tries to separate lexer from parser rules.

  Example:

   token ::= `identifier` ;	// using StandardLexerRules ignored ::= `spaces` ; ignored ::= `newline` ; ignored ::= comment ; comment ::= "//" char_minus_newline_list_opt ; char_minus_newline ::= chars - newline; char_minus_newline_list ::= char_minus_newline_list char_minus_newline; char_minus_newline_list ::= char_minus_newline ; char_minus_newline_list_opt ::= char_minus_newline_list; char_minus_newline_list_opt ::= ;  // nothing 

  Mind that the builder input can not be a text file, it must be wrapped into Syntax. Use syntax builder to convert a text into a Syntax object.

  Java code fragment:

   SyntaxSeparation separation = new SyntaxSeparation(new Syntax(myRules)); LexerBuilder builder = new LexerBuilder(separation.getLexerSyntax(), separation.getIgnoredSymbols()); Lexer lexer = builder.getLexer(); // when using the lexer standalone (without Parser), you must put the token terminal symbols into it now: lexer.setTerminals(separation.getTokenSymbols()); 

  @see fri.patterns.interpreter.parsergenerator.syntax.builder.SyntaxSeparation @see fri.patterns.interpreter.parsergenerator.lexer.StandardLexerRules @author (c) 2002, Fritz Ritzberger

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