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

test/test_parser.c

@@ -0,0 +1,68 @@
+#include "test_utils.h"
+#include "parser.h"
+#include "lexer.h"
+#include "arena.h"
+
+static AstNode* parse_string(const char* src) {
+    Arena* a = malloc(sizeof(Arena));
+    *a = arena_create(1);
+    size_t tcount;
+    ErrorInfo lex_err = {0};
+    Token* tokens = lex(a, src, "test", &tcount, &lex_err);
+    if (!tokens) { arena_destroy(a); free(a); return NULL; }
+    ErrorInfo parse_err = {0};
+    AstNode* ast = parse(a, tokens, tcount, "test", &parse_err);
+    if (!ast) { arena_destroy(a); free(a); return NULL; }
+    // NOTE: arena and tokens must stay alive for AST - leak intentionally in test
+    return ast;
+}
+
+void test_simple_function() {
+    AstNode* ast = parse_string("fn main() { return 42; }");
+    ASSERT(ast != NULL);
+    ASSERT(ast->kind == AST_PROGRAM);
+    ASSERT(ast->as.program.fn_count == 1);
+    AstNode* fn = ast->as.program.functions[0];
+    ASSERT(fn->kind == AST_FUNCTION);
+}
+
+void test_arithmetic_expr() {
+    AstNode* ast = parse_string("fn main() { return 1 + 2 * 3; }");
+    ASSERT(ast != NULL);
+    AstNode* body = ast->as.program.functions[0]->as.function.body;
+    AstNode* ret = body->as.block.stmts[0];
+    ASSERT(ret->kind == AST_RETURN_STMT);
+    AstNode* expr = ret->as.return_stmt.expr;
+    ASSERT(expr->kind == AST_BINARY_EXPR);
+    ASSERT(expr->as.binary.op == OP_ADD);
+    // 1 + (2 * 3): right should be *, left should be 1
+    ASSERT(expr->as.binary.right->kind == AST_BINARY_EXPR);
+    ASSERT(expr->as.binary.right->as.binary.op == OP_MUL);
+}
+
+void test_if_statement() {
+    AstNode* ast = parse_string("fn main() { if true { return 1; } else { return 0; } }");
+    ASSERT(ast != NULL);
+}
+
+void test_while_loop() {
+    AstNode* ast = parse_string("fn main() { while true { return; } }");
+    ASSERT(ast != NULL);
+}
+
+void test_function_with_params() {
+    AstNode* ast = parse_string("fn add(a: i64, b: i64) -> i64 { return a + b; }");
+    ASSERT(ast != NULL);
+    AstNode* fn = ast->as.program.functions[0];
+    ASSERT(fn->as.function.param_count == 2);
+    ASSERT(fn->as.function.return_type == TYPE_I64);
+}
+
+int main(void) {
+    TEST_RUN(test_simple_function);
+    TEST_RUN(test_arithmetic_expr);
+    TEST_RUN(test_if_statement);
+    TEST_RUN(test_while_loop);
+    TEST_RUN(test_function_with_params);
+    return test_summary();
+}