refactor(argparse): 将null替换为nullptr以提高C++兼容性

- 在argparse库中将所有null指针常量替换为nullptr
- 更新头文件和源文件中的指针初始化和比较操作
- 修改测试文件中的相关断言检查
- 更新AST定义文件中的注释说明

libs/pproc/src/pproc_expand.c

@@ -22,7 +22,7 @@ static scc_lexer_tok_t stringify_argument(scc_pproc_expand_t *ctx,
     scc_str_append_ch(&str, '\"'); // 左引号
 
     int need_space = 0; // 是否需要插入空格
-    scc_lexer_tok_t *tok = null;
+    scc_lexer_tok_t *tok = nullptr;
     scc_vec_foreach(*arg_tokens, i) {
         tok = &scc_vec_at(*arg_tokens, i);
         if (tok->type == SCC_TOK_BLANK) {
@@ -61,10 +61,10 @@ static scc_lexer_tok_t concatenate_tokens(scc_pproc_expand_t *ctx,
                                           const scc_lexer_tok_t *left,
                                           const scc_lexer_tok_t *right) {
     scc_str_t new_lex = scc_str_from_cstr("");
-    if (left != null) {
+    if (left != nullptr) {
         scc_str_append(&new_lex, &left->lexeme);
     }
-    if (right != null) {
+    if (right != nullptr) {
         scc_str_append(&new_lex, &right->lexeme);
     }
 
@@ -154,7 +154,7 @@ void scc_pproc_expand_by_src(scc_pproc_macro_table_t *macro_table,
     scc_lexer_tok_vec_t output_vec;
     scc_pproc_expand_by_vec(macro_table, &expaned_buffer, &output_vec, false,
                             need_keep_org_pos);
-    Assert(output->cap == 0 && output->data == null); // FIXME hack it
+    Assert(output->cap == 0 && output->data == nullptr); // FIXME hack it
     *output = scc_lexer_array_to_ring(&output_vec);
 }
 
@@ -186,7 +186,7 @@ static void disable(scc_pproc_expand_t *expand_ctx,
                     const scc_pproc_macro_t *macro) {
     scc_pproc_macro_t *expanded_macro =
         scc_pproc_macro_new(&macro->name, macro->type);
-    if (expanded_macro == null) {
+    if (expanded_macro == nullptr) {
         LOG_FATAL("Out of memory");
     }
     scc_pproc_macro_table_set(expand_ctx->expanded_set, expanded_macro);
@@ -200,7 +200,7 @@ static void enable(scc_pproc_expand_t *expand_ctx,
 static cbool need_skip(scc_pproc_expand_t *expand_ctx,
                        const scc_pproc_macro_t *macro) {
     return scc_pproc_macro_table_get(expand_ctx->expanded_set, &macro->name) !=
-           null;
+           nullptr;
 }
 
 static inline void
@@ -322,7 +322,7 @@ static void rescan(scc_pproc_expand_t *expand_ctx,
 
     scc_pproc_macro_t *end_macro =
         scc_pproc_macro_table_get(expand_ctx->macro_table, &end_tok->lexeme);
-    if (end_macro == null || end_macro->type != SCC_PP_MACRO_FUNCTION) {
+    if (end_macro == nullptr || end_macro->type != SCC_PP_MACRO_FUNCTION) {
         goto RETURN;
     }
 
@@ -387,12 +387,12 @@ static void concact(scc_pproc_expand_t *ctx, scc_lexer_tok_vec_t *tok_buffer,
 
     scc_lexer_tok_t *left;
     if (left_idx < 0) {
-        left = null;
+        left = nullptr;
         left_idx = 0; // FIXME for free tok_buffer
     } else {
         left = &scc_vec_at(*tok_buffer, left_idx);
         if (gnu_va_arg_extend && left->type == SCC_TOK_COMMA) {
-            left = null;
+            left = nullptr;
         }
     }
 
@@ -468,7 +468,7 @@ static inline void expand_function_macro(scc_pproc_expand_t *ctx,
 
             scc_lexer_tok_t *right_tok;
             if (right_idx >= (int)scc_vec_size(macro->replaces)) {
-                right_tok = null;
+                right_tok = nullptr;
             } else {
                 right_tok = &scc_vec_at(macro->replaces, right_idx);
             }
@@ -488,7 +488,7 @@ static inline void expand_function_macro(scc_pproc_expand_t *ctx,
             }
 
             scc_lexer_tok_t *right =
-                scc_vec_size(right_vec) ? &scc_vec_at(right_vec, 0) : null;
+                scc_vec_size(right_vec) ? &scc_vec_at(right_vec, 0) : nullptr;
 
             // GNU ## extention
             if (scc_strcmp(scc_str_as_cstr(&(right_tok->lexeme)),
@@ -559,7 +559,7 @@ static inline void expand_object_macro(scc_pproc_expand_t *ctx,
 
             scc_lexer_tok_t *right;
             if (right_idx >= (int)scc_vec_size(macro->replaces)) {
-                right = null;
+                right = nullptr;
             } else {
                 right = &scc_vec_at(macro->replaces, right_idx);
             }
@@ -588,7 +588,7 @@ static cbool parse_defined(scc_pproc_expand_t *expand_ctx, scc_pos_t *tok_pos) {
         }
 
         if (scc_pproc_macro_table_get(expand_ctx->macro_table,
-                                      &next_tok.lexeme) == null) {
+                                      &next_tok.lexeme) == nullptr) {
             scc_lexer_tok_drop(&next_tok);
             scc_lexer_gen_number_false(&next_tok);
         } else {
@@ -609,7 +609,7 @@ static cbool parse_defined(scc_pproc_expand_t *expand_ctx, scc_pos_t *tok_pos) {
     } else if (scc_get_tok_subtype(next_tok.type) ==
                SCC_TOK_SUBTYPE_IDENTIFIER) {
         if (scc_pproc_macro_table_get(expand_ctx->macro_table,
-                                      &next_tok.lexeme) == null) {
+                                      &next_tok.lexeme) == nullptr) {
             scc_lexer_tok_drop(&next_tok);
             scc_lexer_gen_number_false(&next_tok);
         } else {
@@ -649,7 +649,7 @@ void scc_pproc_expand_macro(scc_pproc_expand_t *expand_ctx) {
         scc_pproc_macro_t *macro =
             scc_pproc_macro_table_get(expand_ctx->macro_table, &tok.lexeme);
 
-        if (macro == null || need_skip(expand_ctx, macro)) {
+        if (macro == nullptr || need_skip(expand_ctx, macro)) {
             // FIXME maybe keyword is error or don't parse c keyword or number
             tok.type += SCC_TOK_DISABLED;
             scc_vec_push(expand_ctx->output, tok);