LR(1)表驱动语法分析程序

 1 /*
 2  * LR(1) 语法分析
 3  */
 4 #include <stdio.h>
 5 #include <stdlib.h>
 6 #include <string.h>
 7 
 8 #include "Common.h"
 9 #include "LRCal.h"
10 #include "LRMigrate.h"
11 #include "Stack.h"
12 
13 #define NEXTWORD(s) ((*(s)==0)?SYM_EOF:*((s)++))
14 
15 extern char *Grammer[];
16 
17 void LRParse(struct LRElement **LRTable, unsigned char *InputString)
18 {
19     printf("-------- Parse --------\n");
20     struct Stack *SymbolStack = BuildStack(1024);
21     Push(SymbolStack, 0);                // push $;
22     Push(SymbolStack, 0);                // push start state s0;
23     int Word = NEXTWORD(InputString);    // word <- NextWord();
24     int State = 0;
25     while (true)                        // while (true)
26     {
27         State = Top(SymbolStack);        // state <- top of stack;
28         printf("State: %d\tWord: %c \t", State, Word);
29         if (LRTable[State][Word].Action == Reduce)    // if (Action[state, word] = "reduce A->β")
30         {
31             printf("reduce %d", (int)LRTable[State][Word].ActionValue);
32 
33             char *Production = Grammer[LRTable[State][Word].ActionValue - 1];
34             int ProductSize = strlen(Production) - 1;
35             // pop 2*|β| symbols;
36             ProductSize *= 2;
37             while (ProductSize--)
38             {
39                 Pop(SymbolStack);
40             }
41             // state <- top of stack;
42             State = Top(SymbolStack);
43             // push A;
44             int LeftUnterminal = (int)Production[0];
45             Push(SymbolStack, LeftUnterminal);
46             // push Goto[State, A];
47             Push(SymbolStack, (int)LRTable[State][LeftUnterminal].ActionValue);
48         }
49         else if (LRTable[State][Word].Action == Shift)    // else if (Action[state, word] = "shift si")
50         {
51             printf("shift %d", (int)LRTable[State][Word].ActionValue);
52             // push word;
53             Push(SymbolStack, Word);
54             // push si;
55             Push(SymbolStack, LRTable[State][Word].ActionValue);
56             // word <- NextWord();
57             Word = NEXTWORD(InputString);
58         }
59         else if (LRTable[State][Word].Action == Accept)    // else if (Action[state, word] = "accept")
60         {
61             printf("accept\n");
62             break;
63         }
64         else
65         {
66             printf("Syntax Error!\n");
67             exit(3);
68         }
69         printf("\n");
70     }
71     printf("Grammer Parse Success!\n");
72 }
联动：LR(1)表生成算法演示程序
全部代码文件：https://files.cnblogs.com/rexfield/LR.zip
posted on 2013-08-31 17:15 RexfieldVon 阅读(861) 评论(0) 编辑收藏举报