www.pudn.com > LexYaccProgs.zip > EXPRLEX.L

 
  (* Lexical analyzer for the sample Yacc program in Expr.y. *) 
 
L				[A-Za-z] 
D				[0-9] 
 
%% 
 
  var result : integer; 
 
{D}+(\.{D}+)?([Ee][+-]?{D}+)?	begin 
				  val(yytext, yylval.yyReal, result); 
				  if result=0 then 
				    return(NUM) 
				  else 
				    return(ILLEGAL) 
				end; 
 
{L}				begin 
				  yylval.yyInteger := ord(upCase(yytext[1]))- 
				                      ord('A')+1; 
				  return(ID) 
				end; 
 
" "             		; 
 
.				| 
\n				returnc(yytext[1]);