编译原理之语义分析（C语言）_斯武丶风晴

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编译原理之语义分析（C语言）

(2011-04-18 00:19:32)

标签：

杂谈

编译原理之语义分析*（C语言）
一继承的词法来自

http://blog.sina.com.cn/s/blog_67c9fc300100srad.html

二继承的语法来自

http://blog.sina.com.cn/s/blog_67c9fc300100srar.html

============================================================================
//语义分析
//main.c
//@author langx

#include "stdio.h"                  //定义I/O库所用的某些宏和变量
#include "string.h"                 //定义字符串库函数
#include "conio.h"                  //提供有关屏幕窗口操作函数
#include "ctype.h"                  //分类函数
#define LEN 6
char prog[80]= {'\0'},
               token[80]= {'\0'};                    //存放构成单词符号的字符串
char ch;
int syn,                           //存放单词字符的种别码
    n,
    sum,                           //存放整数型单词
    m,p;                           //p是缓冲区prog的指针，m是token的指针
char *rwtab[LEN]= {"begin","if","then","while","do","end"};
int kk,q;
struct
{
   char result1[8];
   char ag11[8];
   char op1[8];
   char ag21[8];
} quad[20];
char *factor();
char *expression_r();
int yucu();
char *term();
int statement();
int lrparser();
char *newtemp();
scaner();
emit(char *result,char *ag1,char *op,char *ag2);

int lrparser()
{
   int schain=0;
   kk=0;
   if (syn==1)
   {
       scaner();
       schain=yucu();
       if(syn==6)
       {
           scaner();
           if((syn==0)&&(kk==0)) printf("Success!\n");
       }
       else
       {
           if(kk!=1)printf("short of 'end' !\n");
           kk=1;
           getch();
           exit(0);
       }
   }
   else
   {
       printf("short of 'begin' !\n");
       kk=1;
       getch();
       exit(0);
   }
   return (schain);
}
int yucu()
{
   int schain=0;
   schain=statement();
   while(syn==26)
   {
       scaner();
       schain=statement();
   }
   return (schain);
}
int statement()
{
   char tt[8],eplace[8];
   int schain=0;
   if (syn==10)
   {
       strcpy(tt,token);
       scaner();
       if(syn==18)
       {
           scaner();
           strcpy(eplace,expression_r());
           emit(tt,eplace,"","");
           schain=0;
       }
       else
       {
           printf("short of sign ':=' !\n");
           kk=1;
           getch();
           exit(0);
       }
       return (schain);
   }
}
char *expression_r()
{
   char *tp,*ep2,*eplace,*tt;
   tp=(char *)malloc(12);
   ep2=(char *)malloc(12);
   eplace=(char *)malloc(12);
   tt=(char *)malloc(12);
   strcpy(eplace,term());
   while((syn==13)||(syn==14))
   {
       if (syn==13)strcpy(tt,"+");
       else strcpy(tt,"-");
       scaner();
       strcpy(ep2,term());
       strcpy(tp,newtemp());
       emit(tp,eplace,tt,ep2);
       strcpy(eplace,tp);
   }
   return (eplace);
}
char *term()
{
   char *tp,*ep2,*eplace,*tt;
   tp=(char *)malloc(12);
   ep2=(char *)malloc(12);
   eplace=(char *)malloc(12);
   tt=(char *)malloc(12);
   strcpy(eplace,factor());
   while((syn==15)||(syn==16))
   {
       if (syn==15)strcpy(tt,"*");
       else strcpy(tt,"/");
       scaner();
       strcpy(ep2,factor());
       strcpy(tp,newtemp());
       emit(tp,eplace,tt,ep2);
       strcpy(eplace,tp);
   }
   return (eplace);
}
char *factor()
{
   char *fplace;
   fplace=(char *)malloc(12);
   strcpy(fplace,"");
   if(syn==10)
   {
       strcpy(fplace,token);
       scaner();
   }
   else if(syn==11)
   {
       itoa(sum,fplace,10);
       scaner();
   }
   else if(syn==27)
   {
       scaner();
       fplace=expression_r();
       if(syn==28) scaner();
       else
       {
           printf("error on ')' !\n");
           kk=1;
           getch();
           exit(0);
       }
   }
   else
   {
       printf("error on '(' !\n");
       kk=1;
       getch();
       exit(0);
   }
   return (fplace);
}
char *newtemp()
{
   char *p;
   char m[8];
   p=(char *)malloc(8);
   kk++;
   itoa(kk,m,10);
   strcpy(p+1,m);
   p[0]='t';
   return(p);
}
scaner()
{
   sum=0;
   for(m=0; m<8; m++)token[m++]=NULL;
   m=0;
   ch=prog[p++];
   while(ch==' ')ch=prog[p++];
   if(((ch<='z')&&(ch>='a'))||((ch<='Z')&&(ch>='A')))
   {
       while(((ch<='z')&&(ch>='a'))||((ch<='Z')&&(ch>='A'))||((ch>='0')&&(ch<='9')))
       {
           token[m++]=ch;
           ch=prog[p++];
       }
       p--;
       syn=10;
       token[m++]='\0';
       for(n=0; n<6; n++)
           if(strcmp(token,rwtab[n])==0)
           {
               syn=n+1;
               break;
           }
   }
   else if((ch>='0')&&(ch<='9'))
   {
       while((ch>='0')&&(ch<='9'))
       {
           sum=sum*10+ch-'0';
           ch=prog[p++];
       }
       p--;
       syn=11;
   }
   else switch(ch)
       {
       case '<':
           m=0;
           ch=prog[p++];
           if(ch=='>')
           {
               syn=21;
           }
           else if(ch=='=')
           {
               syn=22;
           }
           else
           {
               syn=20;
               p--;
           }
           break;
       case '>':
           m=0;
           ch=prog[p++];
           if(ch=='=')
           {
               syn=24;
           }
           else
           {
               syn=23;
               p--;
           }
           break;
       case ':':
           m=0;
           ch=prog[p++];
           if(ch=='=')
           {
               syn=18;
           }
           else
           {
               syn=17;
               p--;
           }
           break;
       case '+':
           syn=13;
           break;
       case '-':
           syn=14;
           break;
       case '*':
           syn=15;
           break;
       case '/':
           syn=16;
           break;
       case '(':
           syn=27;
           break;
       case ')':
           syn=28;
           break;
       case '=':
           syn=25;
           break;
       case ';':
           syn=26;
           break;
       case '#':
           syn=0;
           break;
       default:
           syn=-1;
           break;
       }
}
emit(char *result,char *ag1,char *op,char *ag2)
{
   strcpy(quad[q].result1,result);
   strcpy(quad[q].ag11,ag1);
   strcpy(quad[q].op1,op);
   strcpy(quad[q].ag21,ag2);
   q++;
}
main()
{
   int j;
   printf("\nThe significance of the figures:\n"
           "1.figures 1 to 6 said Keyword\n"
           "2.figures 10 and 11 said Other indicators\n"
           "3.figures 13 to 28 said Operators\n");

   q=p=kk=0;

   printf("\nplease input string: (end with '#')\n");
   do
   {
       scanf("%c",&ch);
       prog[p++]=ch;
   }
   while(ch!='#');
   p=0;
   scaner();
   lrparser();
   if(q>19)printf(" to long sentense!\n");
   else for (j=0; j
   getch();
}

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