lexan.c

pascal 词法分析器

                     state = 14;
                   else
                     state = fail();
                   break;
              case 14:c = nextchar();
                   if(isdigit(c))
                      state = 15;
                   else
                   		state=fail();
                   break;
              case 15:
                   c = nextchar();
                   if(isdigit(c))
                      state = 15;
                   else if(c == 'e'|| c == 'E')
                      state = 16;
                   else
                      state = fail();
                   break;
              case 16:
                   c= nextchar();
                   if(isdigit(c))
                      state = 18;
                   else if(c == '+' || c == '-')
                      state = 17;
                   else state=fail();
                   break;
              case 17:
                   c = nextchar();
                   if(isdigit(c))
                      state = 18;
                   else
                      state=fail();
                   break;
              case 18:
                   c = nextchar();
                   if(isdigit(c))
                   state = 18;
                   else
                   state = 19;
                   break;
              case 19:
                   back();
                   tokenValue=installSymbol(NUM);
                   adjustPos();
                   begin=forward+1;
                   return NUM;
              case 20:													/*开始匹配无符号数，有小数点*/
                   start=20;
                   c=nextchar();
                   if(isdigit(c)) state=21;
                   else state=fail();
                   break;
              case 21:
                   c=nextchar();
                   if(isdigit(c)) 
                     state=21;
                   else if(c=='.')
                     state=22;
                   else
                     state=fail();
                   break;
              case 22:
                   c=nextchar();
                   if(isdigit(c))
                     state=23;
                   else
                     state=fail();
                   break;                     
              case 23:
                   c=nextchar();
                   if(isdigit(c))
                     state=23;
                   else
                     state=24;
                   break;
              case 24:
                   back();
                   tokenValue=installSymbol(NUM);
                   adjustPos();
                   begin=forward+1;
                   return NUM;
              case 25:													/*开始匹配无符号整数*/                
                   start=25;
                   c=nextchar();
                   if(isdigit(c))
                     state=26;
                   else state=fail();
                   break;
              case 26:                  
                   c=nextchar();
                   if(isdigit(c)) state=26;
                   else           state=27;
                   break;
              case 27:             
                   back();
                   tokenValue=installSymbol(NUM);
                   adjustPos();
                   begin=forward+1;
                   return NUM;
              case 28:											/*匹配符号*/
                   start=28;
                   c=nextchar();
                   if(c==':')
                   state=29;
                   else if(c=='{')
                   state=32;
                   else if(c=='\'')
                   state=35;                  
                   else if(c=='(')
                   state=38;
                   else if(c==';'||c==')'||c=='['||c==']'||c=='+'||c=='-'||c=='*'||c=='/'||c=='.')
                   state=44;
                   else
                   state=fail();
                   break;                  
              case 29:
                   c=nextchar();
                   if(c=='='){
                        adjustPos();					/*state 30*/
                   		begin=forward+1;
                   		return ASSIGN;	
                   }else{								/*state 31*/
                   		back();
                   		adjustPos();
                   		begin=forward+1;
                   		return COLON;	
                   }
              case 32:                    
					c=nextchar();
					if(c=='}'){						/*state 33*/
					state=0,begin=forward+1;
					}
					else if(c==EOF){				/*state 34*/
					adjustPos();
					error(tokPos,"unterminited comment.");
					return 0;
					}
					else if(c=='\n'){
                         adjustPos();
                         newLine();
                         state=32;
                    }
					else
						state=32;
					break;
              case 35:
                   c=nextchar();
                   if(c=='\'')
                      state=36;
                   else if(c=='\n')
                      state=37;
                   else 
                   	  state=35;
                   break;
              case 36:
                   tokenValue=installLiteral();
                   adjustPos();
                   begin=forward+1;
                   return LITERAL;
              case 37:/*如果到行结束,仍未找到匹配的单引号,则给出错误信息，从下一行开始继续分析*/
                   adjustPos();
                   error(tokPos,"Missing terminating \' character.");
                   state=0;
                   begin=forward+1;
                   break;
              case 38:
                   c=nextchar();
                   if(c=='*'){
                   	state=39;break;
                   }
                   else{
                      back();
                      adjustPos();									/*state 43*/
                      begin=forward+1;
                      return LPAREN;     
                   }
                             
              case 39:
                   c=nextchar();
                   if(c=='*')
                   state=40;
                   else if(c==EOF){
                       adjustPos();												/*state 42*/
                  	   error(tokPos,"Unterminited comment.");
				       return 0;/*直接到输入结束了return 0 */                 	
                   }
                   else if(c=='\n'){
                        adjustPos();
                        newLine();
                        state=39;
                   }
                   else{
                       state=39;                        
                   }
                   break;
              case 40:
                   c=nextchar();
                   if(c==')'){															/*state 41*/
                   		state=0,begin=forward+1;
                   }else if(c==EOF){
                         adjustPos();												/*state 42*/
                   		 error(tokPos,"Unterminited comment.");
						 return 0;
                   }
                   else if(c=='\n'){
                        adjustPos();
                        newLine();
                        state=39;
                   }
                   else{
                         state=39;      
                   } 
                   break;
              case 44:
                     adjustPos();
              		 begin=forward+1;
              		 switch(c){
              		 	case ';':return SEMICOLON;
						case ')':return RPAREN;
						case '[':return LBRACK;
						case ']':return RBRACK;
						case '+':return PLUS;
						case '-':return MINUS;
                        case '.':return DOT;              		 		
              		 	case '*':return TIMES;
              		 	case '/':return DIVIDE;
              		 	default:break;
              		 }
              		 break;
              case 45:
              	     start=45;							/*匹配错误字符或者结束*/	
              		 c=nextchar();
              		 if(c==EOF){
              		  printf("LEXICAL ANALYSIS FINISHED.\n");
              		  return 0;	
              		 }else{
                        adjustPos();
              		 	error(tokPos,"Illegal character.");
              		 	begin=forward+1;
              		 	state=0;	
              		 }
              		 break;
              default:printf("UNKNOWN COMPILE ERROR\n");return 0;
                                
                       
              
       }      
    }
}