📄 byylscanner.java
字号:
case '[':
currentToken.name.append(ch);
currentToken.code=59;
currentToken.address=-1;
currentToken.label=labelCount++;
outPut();
ch=getNextChar();
break;
case ']':
currentToken.name.append(ch);
currentToken.code=60;
currentToken.address=-1;
currentToken.label=labelCount++;
outPut();
ch=getNextChar();
break;
case 10:
ch=getNextChar();
break;
case 13:
ch=getNextChar();
break;
case ' ': ch=getNextChar();
break;
case ' ': ch=getNextChar(); //Tab键
break;
case 1000: error(4); //结束
break;
default:
error(1);
ch=getNextChar();
break;
}
}
/**
*输出和保存token串并填符号表
*/
public void outPut()
{
int flag=0,m,i; //输出token字
if(currentToken.code==3) //由于begin要匹配end;或end.不管哪种情况都匹配两次
beginCode+=2;
if(currentToken.code==11)
endCode++;
if(currentToken.code==47||currentToken.code==52)
if(endCode%2==1)
endCode++; //程序正常结束
if(currentToken.address==-1) //保留字
tokenTextArea.append(currentToken.label +" ( "+currentToken.code+","+"_ "+")"+" "+currentToken.name+"\n");
else
tokenTextArea.append(currentToken.label +" ( "+currentToken.code+","+currentToken.address+")"+" "+currentToken.name+"\n");
//保存token串
//tokenList[]从1开始
tokenList[tokenCount].label=currentToken.label;
tokenList[tokenCount].address=currentToken.address;
tokenList[tokenCount].code=currentToken.code;
tokenList[tokenCount].name.append(currentToken.name.toString());
tokenCount++;
if((currentToken.code==35)||(currentToken.code==36))
{
flag=numberExist();
if(flag==-1)
{
switch(currentToken.code)
{
case 35:currentSymbol.type.append("整");
currentSymbol.kind.append("常数");
break;
case 36:currentSymbol.type.append("实");
currentSymbol.kind.append("常数");
break;
}
currentSymbol.name.start=0;
currentSymbol.name.length=0;
currentSymbol.addr=currentToken.address;
currentSymbol.val.append(currentToken.name.toString());
currentSymbol.sign.append(currentToken.name.toString());
symbolTableTextArea.append(+currentSymbol.addr+" "+currentSymbol.type+" "+currentSymbol.kind+" "+currentSymbol.val+" "+currentSymbol.sign+"\n");
symbolList[varCount].sign.append(currentSymbol.sign.toString());
symbolList[varCount].name.start=currentSymbol.name.start;
symbolList[varCount].name.length=currentSymbol.name.length;
symbolList[varCount].type.append(currentSymbol.type.toString());
symbolList[varCount].val.append(currentSymbol.val.toString());
symbolList[varCount].kind.append(currentSymbol.kind.toString());
symbolList[varCount].addr=currentSymbol.addr;
varCount++;
}
}
//查填符号表和字母表
if((currentToken.code==34)||(currentToken.code==37))
{
flag=wordExist();
if(flag==-1) //字母表中没有
{
currentSymbol.name.start=alphabet.length();
currentSymbol.name.length=currentToken.name.length();
currentSymbol.addr=currentToken.address;//入口地址
currentSymbol.sign.append(currentToken.name.toString());
alphabet.append(currentToken.name);
symbolTableTextArea.append(+currentSymbol.addr+" "+currentSymbol.name.start+" "+currentSymbol.name.length+" "+currentSymbol.type+" "+currentSymbol.kind+" "+currentSymbol.val+" "+currentSymbol.sign+"\n");
symbolList[varCount].sign.append(currentSymbol.sign.toString());
symbolList[varCount].name.start=currentSymbol.name.start;
symbolList[varCount].name.length=currentSymbol.name.length;
symbolList[varCount].type.append(currentSymbol.type.toString());
symbolList[varCount].val.append(currentSymbol.val.toString());
symbolList[varCount].kind.append(currentSymbol.kind.toString());
symbolList[varCount].addr=currentSymbol.addr;
varCount++;
}
//clear the currentToken
}
currentToken.name.delete(0,currentToken.name.length());
currentSymbol.sign.delete(0,currentSymbol.sign.length());
currentSymbol.type.delete(0,currentSymbol.type.length());
currentSymbol.val.delete(0,currentSymbol.val.length());
currentSymbol.kind.delete(0,currentSymbol.kind.length());
currentSymbol.name.start=0;
currentSymbol.name.length=0;
}
/**
*检测数字是否在符号表中
*@return 在符号表中就返回入口地址,不在就返回-1
*/
public int numberExist()
{
int flag=-1,i;
for(i=0;i<varCount;i++)
{
if((symbolList[i].name.start==0)&&(symbolList[i].name.length==0)&&(symbolList[i].val.toString().equals(currentToken.name.toString())))
return i;
}
return flag;
}
/**
*检查标识符是否在字母表中
*@return 在符号表中就返回入口地址,不在就返回-1
*/
public int wordExist()
{
int flag=-1;
for(int i=0;i<varCount;i++) //如果在符号表中则返回入口地址否则返回-1
{
if(currentToken.name.toString().equals(alphabet.substring(symbolList[i].name.start,symbolList[i].name.start+symbolList[i].name.length)))
flag=symbolList[i].addr;
}
return flag;
}
/**
*错误处理
*/
public void error(int a)
{ errorCount++;
switch(a)
{
case 0: resultTextArea.append("错误"+errorCount+"整数出错于"+rowCount+"行"+columnCount+"列"+"\n");break;
case 1: resultTextArea.append("错误"+errorCount+"非法字符于"+rowCount+"行"+columnCount+"列"+"\n");break;
case 2: resultTextArea.append("错误"+errorCount+"实常数出错于"+rowCount+"行"+columnCount+"列"+"\n"); break;
case 3: resultTextArea.append("错误"+errorCount+"没有匹配的注释符"+rowCount+"行"+columnCount+"列"+"\n"); break;
case 4: resultTextArea.append("错误"+errorCount+"begin和end不匹配或程序非正常结束"+"\n"); break;
case 5: resultTextArea.append("错误"+errorCount+"未声明的字符出现于"+rowCount+"行"+columnCount+"列"+"\n");break;
}
}
/**
*获得下一个token,将其保存在属性变量中
*/
public void getNextToken()
{
if(tokenId<tokenCount)
{
code=tokenList[tokenId].code;
address=tokenList[tokenId].address;
ID.delete(0,ID.length());
ID.append(tokenList[tokenId].name.toString());
tokenId++;
}
else
code=-1;
}
/**
*分析说明语句之前是否正确,然后调用declare()进行说明语句的分析<br>
* 调用beginAnalyse()进行其它语句的分析
*@see #declare()
*@see #beginAnalyse()
*/
public void parser()
{
int a;
if(errorCount>0)
{
resultTextArea.append("\n无法进行语法/语义分析，请先改正词法分析时出现的错误\n");
return;
}
else
analyseInit();
//建立四元
getNextToken();
if(code==21||code==22) //program or procedure
{
getNextToken();
if(code==34) //标志符
{
getNextToken();
if(code==52)//分号
{
getNextToken();
lineOfPro++;
}
else
{anaError(3); return;}
if (code!=31)
{anaError(4);return ;}
else
while((code==31)) //var
{
a=declare();
if(a==-1)
return ;
}
//变量说明分析
if(code==3)
{
if(beginAnalyse()==-1)
return;
if((code!=47)&&(code!=52))
anaError(29);
}
else
anaError(8);
}
else
anaError(2);
}
else
anaError(1);
if(error_count==0)
{
resultTextArea.setText("");
resultTextArea.append("语法/语义分析的结果:\n\n");
resultTextArea.append("恭喜，已成功通过语法/语义分析");
}
lastresult();
}
/**
*初始化语法分析时用的变量和数组
*/
public void analyseInit()
{
int i;
pos=0;
tokenId=0;
error_count=0;
lineOfEqu=0;
lineOfPro=1;
address=0;
tempCount=TEMPBOUNDARY;
nowAddr=0;
isFor=0;
falseLine=trueLine=0;
ID=new StringBuffer();
expr=new stack[EXP_LEN];
trueAddress=new int[EXP_LEN];
falseAddress=new int[EXP_LEN];
for(i=0;i<EXP_LEN;i++)
{
expr[i] =new stack();
trueAddress[i]=0;
falseAddress[i]=0;
}
Equ=new equ[EQU_LEN];
for(i=0;i<EQU_LEN;i++)
Equ[i]=new equ();
trueAddress=new int[EXP_LEN];
falseAddress=new int[EXP_LEN];
initStack();
}
/**
*分析说明语句并修改符号表
*@return 说明语句是否出错的标志,0 未出错 -1 出错
*/
public int declare()
{
int a=1,i=0,j=0;
int df;
initStack();
if(code==31) //var
{
getNextToken();
if(code==3) //说明语句，不能出现begin
{
anaError(5);
return -1;
}
while((code!=3)&&(code!=-1)&&(code!=31))//只分析一行
{
push(); //标志符
getNextToken();
}
while(pos>i)
{
if(expr[i].cod==34) //是标志符
i++;
else
{ anaError(6);return -1;}
if(expr[i].cod==50)//冒号
{
i++;
df=expr[i].cod;
switch(df)
{
case 4:
for(j=0;j<=i-2;j++)
if(expr[j].addr!=-1)
{
symbolList[expr[j].addr].type.append("布尔");
symbolList[expr[j].addr].kind.append("简变");
}
break;
case 7:
for(j=0;j<=i-2;j++)
if(expr[j].addr!=-1)
{
symbolList[expr[j].addr].type.append("字符");
symbolList[expr[j].addr].kind.append("简变");
}
break;
case 16:
for(j=0;j<=i-2;j++)
if(expr[j].addr!=-1)
{
symbolList[expr[j].addr].type.append("整");
symbolList[expr[j].addr].kind.append("简变");
}
break;
case 24:
for(j=0;j<=i-2;j++)
if(expr[j].addr!=-1)
{
symbolList[expr[j].addr].type.append("实");
symbolList[expr[j].addr].kind.append("简变");
}
break;
default: anaError(6);return -1;
}
i++;
if(expr[i].cod==52) //分号
{i++;lineOfPro++;}
else //bool,char,integer,real后必须是分号
{anaError(7);lineOfPro++; return -1;}
}
else
{
if(expr[i].cod==44)
i++; //逗点
else
{anaError(6); return -1;}
}
}
}
return 0;
}
/**
*处理begin开始的各种语句,调用函数sentenceAnalize()
*@return -1 表示出错<br>
* 非 -1 表示语句生成的第一个四元式的序号
*@see #sentenceAnalize()
*/
public int beginAnalyse()
{
int rtn=0;
getNextToken();
if(code==52)
{ anaError(9);return -1;}
else
{
lineOfPro++; //begin 与后面的语句差一行
if(code==11)
{anaError(10);return -1;}
isChange=1; //简单赋值语句要修改符号表
rtn=sentenceAnalize();
if(rtn==-1) //语句出错，无法预测下一个token
return rtn;
if(code!=11) //end
{
anaError(28);
//lineOfPro++;
return -1;
}
else
{
//lineOfPro++;
getNextToken(); //符号.
}
}
return rtn; //四原式的序号
}
/**
*匹配当前token,调用不同的程序进行分析
*@return -1 表示出错<br>
* 非 -1 表示语句生成的第一个四元式的序号
*@see #startEvaluate()
*@see #startIf()
*@see #startWhile()
*@see #startRepeat()
*@see #startFor()
*/
public int sentenceAnalize()
{
int rtn=0;
switch(code)
{
case 34:
rtn=startEvaluate();
break;
case 14:
rtn=startIf();
break;
case 32:
rtn=startWhile();
break;
case 25:
rtn=startRepeat();
break;
case 13:
rtn=startFor();
break;
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