RelAst.flex

package org.jastadd.relast.ast;

import org.jastadd.relast.ast.RelAstParser.Terminals;

%%

%public
%final
%class RelAstScanner
%extends beaver.Scanner

%type beaver.Symbol 
%function nextToken 
%yylexthrow beaver.Scanner.Exception
%scanerror RelAstScanner.ScannerError

%line
%column
%{
  private StringBuilder stringLitSb = new StringBuilder();
  
  private beaver.Symbol sym(short id) {
    return new beaver.Symbol(id, yyline + 1, yycolumn + 1, yylength(), yytext());
  }

  private beaver.Symbol sym(short id, String text) {
    return new beaver.Symbol(id, yyline + 1, yycolumn + 1, yylength(), text);
  }

  
  public static class ScannerError extends Error {
  	public ScannerError(String message) {
  		super(message);
  	}
  } 
%}

WhiteSpace = [ ] | \t | \f | \n | \r | \r\n
TraditionalComment   = "/*" [^*] ~"*/" | "/*" "*"+ "/"
EndOfLineComment = "//" [^\n|\r|\r\n]*
Comment = {TraditionalComment} | {EndOfLineComment}

ID = [a-zA-Z$][a-zA-Z0-9$_]*
FLOAT  = -?[0-9]+ \. [0-9]+ {Exponent}?
Exponent = [eE] [+-]? [0-9]+
NUM = -?[0-9]+

%state STRING

%%
<YYINITIAL> {
	{WhiteSpace} 	{ /* ignore */ }
	{Comment}		{ /* ignore */ }

	"abstract"		{ return sym(Terminals.ABSTRACT); }
	"rel"			{ return sym(Terminals.RELATION); }

	";"				{ return sym(Terminals.SCOL); }
	":"				{ return sym(Terminals.COL); }
	"::="			{ return sym(Terminals.ASSIGN); }
	"*"				{ return sym(Terminals.STAR); }
	"."				{ return sym(Terminals.DOT); }
	"<"				{ return sym(Terminals.LT); }
	">"				{ return sym(Terminals.GT); }
	"["				{ return sym(Terminals.LBRACKET); }
	"]"				{ return sym(Terminals.RBRACKET); }
	"->"			{ return sym(Terminals.RIGHT); }
	"<->"			{ return sym(Terminals.BIDIRECTIONAL); }

	// ID
	{ID}			{ return sym(Terminals.ID); }
	\"				{ stringLitSb.setLength(0); yybegin(STRING); }
	<<EOF>> 		{ return sym(Terminals.EOF); }
}

<STRING> {
	\"				{ yybegin(YYINITIAL); return sym(Terminals.STRING_LITERAL, stringLitSb.toString()); }
	[^\n\r\"\\]+	{ stringLitSb.append( yytext() ); }
	\\t				{ stringLitSb.append('\t'); }
	\\n				{ stringLitSb.append('\n'); }
	\\r				{ stringLitSb.append('\r'); }
	\\\"			{ stringLitSb.append('\"'); }
	\\				{ stringLitSb.append('\\'); }
}


[^]				{ throw new ScannerError((yyline+1) +"," + (yycolumn+1) + ": Illegal character <"+yytext()+">"); }