testparse.c

编译原理语义分析代码

	fscanf(fp,"%s %s\n",&token,&token1);
	printf("%s %s\n",token,token1);
	es=statement();
	if (es>0) return(es);
	fprintf(fout,"        BR LABEL%d\n",label1);//输出无条件转移指令
	fprintf(fout,"LABEL%d:\n",label2);//设置label2标号
    fscanf(fp,"%s %s\n",&token,&token1);
	printf("%s %s\n",token,token1);
	return(es);
}

//<for_stat>::= for(<expr>,<expr>,<expr>)<statement>
/*
<for_stat>::=for (<expression>;
             @SETlabel↑label1< expression >@BRF↑label2@BR↑label3;
             @SETlabel↑label4 < expression >@BR↓label1) 
             @SETlabel↓label3 <语句 >@BR↓label4@SETlabel↓label2 
动作解释：
1.	@SETlabel↓label1：设置标号label1
2.	@BRF↑label2 ：输出 BRF label2,
3.	@BR↑label3：输出 BR label3,
4.	@SETlabel↓label4：设置标号label4
5.	@BR↑label1：输出 BR label1,
6.	@SETlabel↓label3：设置标号label3
7.	@BR↑label4：输出 BR label4,
8.	@SETlabel↓label2：设置标号label2 
*/
int for_stat()
{
	int es=0,label1,label2,label3,label4;  
	fscanf(fp,"%s %s\n",&token,&token1);
	printf("%s %s\n",token,token1);
	if (strcmp(token,"("))  return(es=5);  //少左括号
	fscanf(fp,"%s %s\n",&token,&token1);
	printf("%s %s\n",token,token1);
	es=expression();
	if (es>0) return(es);
	if (strcmp(token,";")) 	return(es=4);  //少分号
	label1=labelp++;
	fprintf(fout,"LABEL%d:\n",label1);//设置label1标号
	fscanf(fp,"%s %s\n",&token,&token1);
	printf("%s %s\n",token,token1);
	es=expression();
	if (es>0) return(es);
	label2=labelp++;
	fprintf(fout,"        BRF LABEL%d\n",label2);//输出假条件转移指令
	label3=labelp++;
	fprintf(fout,"        BR LABEL%d\n",label3);//输出无条件转移指令
	if (strcmp(token,";"))  return(es=4);  //少分号
	label4=labelp++;
	fprintf(fout,"LABEL%d:\n",label4);//设置label4标号
	fscanf(fp,"%s %s\n",&token,&token1);
	printf("%s %s\n",token,token1);
	es=expression();
	if (es>0) return(es);
	fprintf(fout,"        BR LABEL%d\n",label1);//输出无条件转移指令
	if (strcmp(token,")"))  return(es=6); //少右括号
	fprintf(fout,"LABEL%d:\n",label3);//设置label3标号
	fscanf(fp,"%s %s\n",&token,&token1);
	printf("%s %s\n",token,token1);
	es=statement();
	if (es>0) return(es);
	fprintf(fout,"        BR LABEL%d\n",label4);//输出无条件转移指令
	fprintf(fout,"LABEL%d:\n",label2);//设置label2标号
	return(es);
	
}

//<write_stat>::=write <expression>;
//<write_stat>::=write <expression>@OUT;
//动作解释：
//@ OUT：输出 OUT

int write_stat()
{
	int es=0;
	fscanf(fp,"%s %s\n",&token,&token1);
	printf("%s %s\n",token,token1);
	es=expression();
	if (es>0)return(es);
	if (strcmp(token,";"))  return(es=4);  //少分号
	fprintf(fout,"        OUT\n");//输出指令
	fscanf(fp,"%s %s\n",&token,&token1);
	printf("%s %s\n",token,token1);
	return(es);
}

//<read_stat>::=read ID;
//<read_stat>::=read ID↑n LOOK↓n↑d @IN@STI↓d;
//动作解释：
//@LOOK↓n↑d:查符号表n，给出变量地址d; 没有，变量没定义
//@IN：输出IN
//@STI↓d：输出指令代码STI  d


int read_stat()
{
	int es=0,address;
	fscanf(fp,"%s %s\n",&token,&token1);
	printf("%s %s\n",token,token1);
	if (strcmp(token,"ID"))  return(es=3);  //少标识符
	es=lookup(token1,&address);
	if (es>0) return(es);
	fprintf(fout,"        IN   \n");//输入指令
	fprintf(fout,"        STI   %d\n",address);//指令
	fscanf(fp,"%s %s\n",&token,&token1);
	printf("%s %s\n",token,token1);
	if (strcmp(token,";"))  return(es=4);  //少分号
	fscanf(fp,"%s %s\n",&token,&token1);
	printf("%s %s\n",token,token1);
	return(es);
}

//<compound_stat>::={<statement_list>} 
int compound_stat(){   //复合语句函数
	int es=0;
	fscanf(fp,"%s %s\n",&token,&token1);
	printf("%s %s\n",token,token1);
	es=statement_list();
	return(es);
}

//<expression_stat>::=<expression>;|;
int expression_stat()
{
	int es=0;
	if (strcmp(token,";")==0) 
	{
		fscanf(fp,"%s %s\n",&token,&token1);
		printf("%s %s\n",token,token1);
		return(es);
	}
	es=expression();
	if (es>0) return(es);
	if (strcmp(token,";")==0) 
	{
		fscanf(fp,"%s %s\n",&token,&token1);
		printf("%s %s\n",token,token1);
		return(es);
	} else
	{
		es=4;
		return(es);//少分号
	}
}

//<expression>::=ID↑n@LOOK↓n↑d@ASSIGN=<bool_expr>@STO↓d |<bool_expr>

int expression()
{
	int es=0,fileadd;
	char token2[20],token3[40];
	if (strcmp(token,"ID")==0)
	{   
		fileadd=ftell(fp);   //@ASSIGN记住当前文件位置
		fscanf(fp,"%s %s\n", &token2,&token3);
		printf("%s %s\n",token2,token3);
		if (strcmp(token2,"=")==0)  //'='
		{
			int address;
			es=lookup(token1,&address);
			if (es>0) return(es);
			fscanf(fp,"%s %s\n",&token,&token1);
			printf("%s %s\n",token,token1);
			es=bool_expr();
			if (es>0) return(es);
			fprintf(fout,"        STO %d\n",address);

		} else 
		{
			fseek(fp,fileadd,0); //若非'='则文件指针回到'='前的标识符
			printf("%s %s\n",token,token1);
			es=bool_expr();
			if (es>0) return(es);
		}
	}
	
	return(es);
}


//<bool_expr>::=<additive_expr>
//           |< additive_expr >(>|<|>=|<=|==|!=)< additive_expr >
/*
<bool_expr>::=<additive_expr>
|< additive_expr >><additive_expr>@GT
|< additive_expr ><<additive_expr>@LES
|< additive_expr >>=<additive_expr >@GE
|< additive_expr ><=< additive_expr >@LE
|< additive_expr >==< additive_expr >@EQ
|< additive_expr >!=< additive_expr >@NOTEQ
*/
int bool_expr()
{
	int es=0;
	es=additive_expr();
	if(es>0) return(es);
	if ( strcmp(token,">")==0 || strcmp(token,">=")==0
	   ||strcmp(token,"<")==0 || strcmp(token,"<=")==0
	   ||strcmp(token,"==")==0|| strcmp(token,"!=")==0)
	{
		char token2[20];
		strcpy(token2,token);//保存运算符
		fscanf(fp,"%s %s\n",&token,&token1);
		printf("%s %s\n",token,token1);
		es=additive_expr();
		if(es>0) return(es);
		if ( strcmp(token2,">")==0 ) fprintf(fout,"        GT\n");
		if ( strcmp(token2,">=")==0 ) fprintf(fout,"        GE\n");
		if ( strcmp(token2,"<")==0 ) fprintf(fout,"        LES\n");
		if ( strcmp(token2,"<=")==0 ) fprintf(fout,"        LE\n");
		if ( strcmp(token2,"==")==0 ) fprintf(fout,"        EQ\n");
		if ( strcmp(token2,"!=")==0 ) fprintf(fout,"        NOTEQ\n");
	}
	return(es);
}

//<additive_expr>::=<term>{(+|-)< term >} 
//< additive_expr>::=<term>{(+< term >@ADD |-<项>@SUB)}

int additive_expr()
{
	int es=0;
	es=term();
	if(es>0) return(es);
	while (strcmp(token,"+")==0 || strcmp(token,"-")==0)
	{
		char token2[20];
		strcpy(token2,token);
		fscanf(fp,"%s %s\n",&token,&token1);
		printf("%s %s\n",token,token1);
		es=term();
		if(es>0) return(es);
		if ( strcmp(token2,"+")==0 ) fprintf(fout,"        ADD\n");
		if ( strcmp(token2,"-")==0 ) fprintf(fout,"        SUB\n");
	}
	return(es);
}

//< term >::=<factor>{(*| /)< factor >} 
//< term >::=<factor>{(*< factor >@MULT | /< factor >@DIV)} 

int term()
{
	int es=0;
	es=factor();
	if(es>0) return(es);
	while (strcmp(token,"*")==0 || strcmp(token,"/")==0)
	{
		char token2[20];
		strcpy(token2,token);
		fscanf(fp,"%s %s\n",&token,&token1);
		printf("%s %s\n",token,token1);
		es=factor();
		if(es>0) return(es);
		if ( strcmp(token2,"*")==0 ) fprintf(fout,"        MULT\n");
		if ( strcmp(token2,"/")==0 ) fprintf(fout,"        DIV\n");
	}
	return(es);
}

//< factor >::=(<additive_expr>)| ID|NUM
//< factor >::=(< expression >)| ID↑n@LOOK↓n↑d@LOAD↓d |NUM↑i@LOADI↓i

int factor()
{
	int es=0;
	
	if (strcmp(token,"(")==0)  
	{
		fscanf(fp,"%s %s\n",&token,&token1);
		printf("%s %s\n",token,token1);
		es=expression();
		if (es>0) return(es);
		if (strcmp(token,")"))  return(es=6); //少右括号
		fscanf(fp,"%s %s\n",&token,&token1);
		printf("%s %s\n",token,token1);
	} else
	{
		
		if (strcmp(token,"ID")==0)
		{
			int address;
			es=lookup(token1,&address);//查符号表，获取变量地址
			if (es>0) return(es);//变量没声明
			fprintf(fout,"        LOAD %d\n",address);
			fscanf(fp,"%s %s\n",&token,&token1);
			printf("%s %s\n",token,token1);
			return(es);
		} 
		if (strcmp(token,"NUM")==0)
		{
			fprintf(fout,"        LOADI %s\n",token1);
			fscanf(fp,"%s %s\n",&token,&token1);
			printf("%s %s\n",token,token1);
			return(es);
		}else
		{
			es=7;//缺少操作数
			return(es);
		}
	}
	return(es);
}