如何让解释器存储变量

Question

我一直在尝试制作一种小编程语言，但我不知道如何让我的解释器存储和调用变量

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

#define MAX_VARIABLES 10

// Structure to store variables
struct Variable {
    char name[50];
    char value[256];
};

// Array to store variables
struct Variable variables[MAX_VARIABLES];
int variableCount = 0;

// Function to find a variable by name
struct Variable* findVariable(const char* name) {
    for (int i = 0; i < variableCount; ++i) {
        if (strcmp(variables[i].name, name) == 0) {
            return &variables[i];
        }
    }
    return NULL; // Variable not found
}

// Function to interpret commands
void interpretCommand(const char* command) {
    if (strncmp(command, "console:write->", 15) == 0) {
        // Extract the message within double quotes
        const char* messageStart = strchr(command, '"');
        const char* messageEnd = strrchr(command, '"');

        if (messageStart != NULL && messageEnd != NULL && messageStart < messageEnd) {
            // Print the message, replacing variables if present
            for (const char* p = messageStart + 1; p < messageEnd; ++p) {
                if (*p == '*') {
                    ++p; // Move past '*'
                    const char* varStart = p;
                    while (*p != '*' && p < messageEnd) {
                        ++p;
                    }

                    char varName[50];
                    strncpy(varName, varStart, p - varStart);
                    varName[p - varStart] = '\0';

                    struct Variable* variable = findVariable(varName);
                    if (variable != NULL) {
                        printf("%s", variable->value);
                    } else {
                        printf("Undefined variable: %s", varName);
                    }
                } else {
                    putchar(*p);
                }
            }
            putchar('\n');
        } else {
            printf("Invalid message format\n");
        }
    } else if (strncmp(command, "console:read->", 14) == 0) {
      // Extract the prompt within double quotes
      const char* promptStart = strchr(command, '"');
      const char* promptEnd = strrchr(command, '"');

      if (promptStart != NULL && promptEnd != NULL && promptStart < promptEnd) {
          // Print the prompt and read user input
          printf("%.*s", (int)(promptEnd - promptStart - 1), promptStart + 1);

          // Read user input
          char userInput[256]; // Adjust size as needed
          fgets(userInput, sizeof(userInput), stdin);

      } else {
          printf("Invalid prompt format\n");
      }
    } else {
        // Check if the command starts with "variableName->"
        char* arrow = strstr(command, "->");
        if (arrow != NULL) {
            *arrow = '\0'; // Separate variable name and value

            // Find or create a variable with the given name
            struct Variable* variable = findVariable(command);
            if (variable == NULL) {
                if (variableCount < MAX_VARIABLES) {
                    strcpy(variables[variableCount].name, command);
                    variable = &variables[variableCount++];
                } else {
                    printf("Maximum number of variables reached\n");
                    return;
                }
            }

            // Copy the value to the variable
            strcpy(variable->value, arrow + 2);
        } else {
            printf("Unknown command\n");
        }
    }
}

int main() {
    // Open the file
    FILE* file = fopen("King.roar", "r");

    if (file == NULL) {
        perror("Error opening file");
        return 1;
    }

    char line[256]; // Assuming a maximum line length of 255 characters

    // Read and interpret each line from the file
    while (fgets(line, sizeof(line), file) != NULL) {
        // Remove newline character if present
        size_t len = strlen(line);
        if (len > 0 && line[len - 1] == '\n') {
            line[len - 1] = '\0';
        }

        // Interpret the command
        interpretCommand(line);
    }

    // Close the file
    fclose(file);

    return 0;
}

这是我存储在 King.roar 中的示例代码

console:read->"Enter your name: "->name
console:read->"Enter your age: "->age
console:write->"Hello *name*!"
console:write->"You are *age* years old!"

由于某种原因，我只得到未定义的变量，我不知道数据是否未存储，或者调用不起作用

我尝试在互联网上查找，但没有找到任何相关内容。感谢您的帮助！

Answer 1

（免责声明：我没有尝试过）。

根据您的代码，您正在通过检查来检查变量

（变量名）->

（寻找 -> 并在箭头处将名字剪掉）。但是您的示例代码使用

->（变量名）

(->name, ->age)，因此在箭头处截断将导致使用空字符串作为变量名称。尝试打印出您最终用于存储的变量的名称，并用 * 和 * 包围 - 我认为您最终会得到 **！