LR0分析程序的设计与实现代码，使用C语言

以下是一个简单的LR(0)分析程序的设计和实现代码，使用了C语言：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define MAX_STATES 100
#define MAX_SYMBOLS 100
#define MAX_PRODUCTIONS 100

// 定义文法
char *grammar[] = {
    "S->E",
    "E->E+T",
    "E->T",
    "T->T*F",
    "T->F",
    "F->(E)",
    "F->id"
};
int num_symbols = 5;

// 定义项目
char *closure(char **I, int n) {
    char **J = I;
    int m = n;
    while (1) {
        int item_added = 0;
        for (int i = 0; i < m; i++) {
            char *item = J[i];
            int dot_pos = strchr(item, '.') - item;
            if (dot_pos == strlen(item) - 1) {
                continue;
            }
            char next_symbol = item[dot_pos + 1];
            if (next_symbol >= 'A' && next_symbol <= 'Z') {
                for (int j = 0; j < num_symbols; j++) {
                    if (grammar[j][0] == next_symbol) {
                        char *new_item = malloc(strlen(grammar[j]) + 4);
                        sprintf(new_item, "%c->.%s", next_symbol, grammar[j] + 3);
                        if (!strstr(J[0], new_item) && !strstr(J[m-1], new_item)) {
                            J[m++] = new_item;
                            item_added = 1;
                        } else {
                            free(new_item);
                        }
                    }
                }
            }
        }
        if (!item_added) {
            break;
        }
    }
    char *closure = malloc(m * (strlen(grammar[0]) + 1));
    strcpy(closure, J[0]);
    for (int i = 1; i < m; i++) {
        strcat(closure, "/");
        strcat(closure, J[i]);
    }
    return closure;
}

// 定义goto函数
int goto(char **I, int n, char X, char **J) {
    int m = 0;
    for (int i = 0; i < n; i++) {
        char *item = I[i];
        int dot_pos = strchr(item, '.') - item;
        if (dot_pos == strlen(item) - 1) {
            continue;
        }
        char next_symbol = item[dot_pos + 1];
        if (next_symbol == X) {
            char *new_item = malloc(strlen(item) + 1);
            strcpy(new_item, item);
            new_item[dot_pos] = next_symbol;
            new_item[dot_pos + 1] = '.';
            J[m++] = new_item;
        }
    }
    char *closure_J = closure(J, m);
    int ret = 1;
    for (int i = 0; i < n; i++) {
        if (strcmp(I[i], closure_J) == 0) {
            ret = 0;
            break;
        }
    }
    if (ret) {
        strcpy(I[n], closure_J);
    }
    free(closure_J);
    return ret ? n + 1 : -1;
}

// 构造LR(0)自动机
char *states[MAX_STATES];
int num_states = 1;
char *queue[MAX_STATES];

void construct_LR0_automaton() {
    char *C = closure((char *[]){"S->.E"}, 1);
    states[0] = C;
    queue[0] = C;
    int head = 0, tail = 1;
    while (head < tail) {
        C = queue[head++];
        for (char symbol = 'A'; symbol <= 'Z'; symbol++) {
            char *J[MAX_PRODUCTIONS];
            int m = goto(C, strlen(C), symbol, J);
            if (m > 0) {
                states[num_states] = J[0];
                for (int i = 1; i < m; i++) {
                    strcat(states[num_states], "/");
                    strcat(states[num_states], J[i]);
                }
                queue[tail++] = states[num_states];
                num_states++;
            }
        }
    }
}

// 定义LR(0)分析表
enum Action {
    SHIFT,
    REDUCE,
    ACCEPT
};

struct TableEntry {
    enum Action action;
    int num;
};

struct TableEntry action[MAX_STATES][MAX_SYMBOLS];
int goto_table[MAX_STATES][MAX_SYMBOLS];

void construct_LR0_table() {
    for (int i = 0; i < num_states; i++) {
        for (int j = 0; j < MAX_SYMBOLS; j++) {
            action[i][j].action = -1;
            goto_table[i][j] = -1;
        }
    }
    for (int i = 0; i < num_states; i++) {
        char *C = states[i];
        char *item = strtok(C, "/");
        while (item) {
            int dot_pos = strchr(item, '.') - item;
            if (dot_pos == strlen(item) - 1) {
                for (int j = 0; j < num_symbols; j++) {
                    if (grammar[j][0] == item[0]) {
                        action[i]['$' - 'A'].action = ACCEPT;
                        action[i]['$' - 'A'].num = j;
                        break;
                    }
                }
            } else {
                char X = item[dot_pos + 1];
                if (X >= 'a' && X <= 'z') {
                    action[i][X - 'A'].action = SHIFT;
                    action[i][X - 'A'].num = goto(states, num_states, X, (char *[]){"", ""});
                } else if (X >= 'A' && X <= 'Z') {
                    int j;
                    for (j = 0; j < num_symbols; j++) {
                        if (grammar[j][0] == X) {
                            break;
                        }
                    }
                    action[i][j].action = REDUCE;
                    action[i][j].num = j;
                }
            }
            item = strtok(NULL, "/");
        }
    }
    for (int i = 0; i < num_states; i++) {
        char *C = states[i];
        char *item = strtok(C, "/");
        while (item) {
            int dot_pos = strchr(item, '.') - item;
            if (dot_pos < strlen(item) - 1) {
                char X = item[dot_pos + 1];
                if (X >= 'A' && X <= 'Z') {
                    goto_table[i][X - 'A'] = goto(states, num_states, X, (char *[]){"", ""});
                }
            }
            item = strtok(NULL, "/");
        }
    }
}

// 测试
int parse_LR0(char *string) {
    int stack[MAX_STATES];
    int top = 0;
    stack[top++] = 0;
    char *input_str = malloc(strlen(string) + 2);
    strcpy(input_str, string);
    strcat(input_str, "$");
    int output[MAX_PRODUCTIONS];
    int num_output = 0;
    while (1) {
        int state = stack[top - 1];
        char a = input_str[0];
        if (action[state][a - 'A'].action == -1) {
            printf("error\n");
            return -1;
        }
        switch (action[state][a - 'A'].action) {
            case SHIFT:
                stack[top++] = action[state][a - 'A'].num;
                input_str++;
                break;
            case REDUCE: {
                int num = action[state][a - 'A'].num;
                output[num_output++] = num;
                char *production = grammar[num];
                int len = strlen(production) - 3;
                for (int i = 0; i < len * 2; i++) {
                    top--;
                }
                state = stack[top - 1];
                stack[top++] = goto_table[state][production[0] - 'A'];
                break;
            }
            case ACCEPT:
                output[num_output++] = num_symbols;
                for (int i = 0; i < num_output; i++) {
                    printf("%s\n", grammar[output[i]]);
                }
                return 0;
        }
    }
}

int main() {
    construct_LR0_automaton();
    construct_LR0_table();
    parse_LR0("id+id*id");
    return 0;
}

这段代码实现了一个简单的LR(0)分析程序，包括构造LR(0)自动机和分析表，以及使用分析表进行语法分析的过程。