feat: L Language v0.1 编译器完整实现

5 阶段编译流水线: 词法分析 → 语法分析(Pratt) → 语义分析(类型推断) → LLVM IR → .exe

模块:
- lexer: 手写状态机, 40 种 Token, // 和 /* */ 注释
- parser: Pratt 表达式解析(9 级优先级) + 递归下降语句/函数
- ast: 14 种节点类型 + 工厂函数
- sema: 作用域链符号表 + 类型推断 + 类型检查
- codegen: AST → LLVM-C API, print_i64/f64/bool 内建
- driver: 命令行 + 流水线串联 + 错误报告
- util: Arena bump allocator (8MB)

测试: 65 单元测试(词法41+语法15+语义9) + 5 集成测试 全部通过

语言特性: i64/f64/bool/void, let不可变变量, if/else, while, 递归函数

src/driver/error.c

@@ -0,0 +1,49 @@
+#include "error.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdarg.h>
+#include <string.h>
+
+void error_init(ErrorList* list) {
+    list->capacity = 8;
+    list->errors = malloc(list->capacity * sizeof(ErrorInfo));
+    list->count = 0;
+    if (!list->errors) list->capacity = 0;
+}
+
+void error_add(ErrorList* list, const char* filename, int line, int col, const char* fmt, ...) {
+    if (!list->errors) return;
+    if (list->count >= list->capacity) {
+        size_t new_cap = list->capacity * 2;
+        ErrorInfo* new_errs = realloc(list->errors, new_cap * sizeof(ErrorInfo));
+        if (!new_errs) return;
+        list->errors = new_errs;
+        list->capacity = new_cap;
+    }
+    char buf[512];
+    va_list args;
+    va_start(args, fmt);
+    int n = vsnprintf(buf, sizeof(buf), fmt, args);
+    va_end(args);
+    if (n < 0) return;
+    char* msg = strdup(buf);
+    char* fname = strdup(filename);
+    if (!msg || !fname) {
+        free(msg); free(fname);
+        return;
+    }
+    list->errors[list->count++] = (ErrorInfo){
+        .message = msg,
+        .filename = fname,
+        .line = line,
+        .col = col,
+    };
+}
+
+void error_print(const ErrorList* list) {
+    for (size_t i = 0; i < list->count; i++) {
+        const ErrorInfo* e = &list->errors[i];
+        fprintf(stderr, "\033[1;31m错误:\033[0m %s:%d:%d: %s\n",
+                e->filename, e->line, e->col, e->message);
+    }
+}