scc/libs/pproc/src/pproc_expand.c

#include <pproc_expand.h>
#include <scc_lexer_utils.h>
#include <scc_pproc.h>

static void rescan(scc_pproc_expand_t *expand_ctx,
                   const scc_pproc_macro_t *macro,
                   scc_lexer_tok_vec_t *tok_buffer);

static scc_lexer_tok_t stringify_argument(scc_pproc_expand_t *ctx,
                                          scc_lexer_tok_vec_t *arg_tokens) {
    // WRITE BY AI
    scc_cstring_t str = scc_cstring_create();
    scc_cstring_append_ch(&str, '\"'); // 左引号

    int need_space = 0; // 是否需要插入空格
    scc_vec_foreach(*arg_tokens, i) {
        scc_lexer_tok_t *tok = &scc_vec_at(*arg_tokens, i);
        if (tok->type == SCC_TOK_BLANK) {
            need_space = 1; // 标记遇到空白
            continue;
        }

        // 需要空格且当前不是第一个有效token，插入一个空格
        if (need_space && i > 0) {
            scc_cstring_append_ch(&str, ' ');
        }

        // 对字符串/字符常量内的 " 和 \ 进行转义
        if (tok->type == SCC_TOK_STRING_LITERAL ||
            tok->type == SCC_TOK_CHAR_LITERAL) {
            // 注意：lex包含两端的引号，需要跳过首尾，转义内部字符
            // 简化：暂不处理内部转义，直接追加
        }
        scc_cstring_append(&str, &tok->lexeme);
        need_space = 0;
    }
    scc_cstring_append_ch(&str, '\"'); // 右引号

    scc_lexer_tok_t result;
    result.type = SCC_TOK_STRING_LITERAL;
    result.lexeme = str;
    if (ctx->need_keep_org_pos)
        result.loc = ctx->call_pos;
    return result;
}

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_cstring_t new_lex = scc_cstring_from_cstr("");
    if (left != null) {
        scc_cstring_append(&new_lex, &left->lexeme);
    }
    if (right != null) {
        scc_cstring_append(&new_lex, &right->lexeme);
    }

    scc_lexer_t lexer;
    scc_sstream_t sstream;
    // new_lex 所有权转移
    scc_sstream_init_by_buffer(&sstream, scc_cstring_as_cstr(&new_lex),
                               scc_cstring_len(&new_lex), true, 8);
    scc_lexer_init(&lexer, scc_sstream_to_ring(&sstream));
    scc_lexer_tok_ring_t *ring = scc_lexer_to_ring(&lexer, 8, true);

    scc_lexer_tok_t result = {0};
    int ok;
    scc_ring_next_consume(*ring, result, ok);
    if (!ok) {
        result.type = SCC_TOK_EOF;
        goto RETURN; // FIXME maybe memleak
    }
    scc_ring_next_consume(*ring, result, ok);
    if (ok) {
        scc_lexer_tok_drop(&result);
        goto RETURN; // FIXME maybe memleak
    }

    scc_lexer_tok_t dummy;
RETURN:
    while (1) {
        scc_ring_next_consume(*ring, dummy, ok);
        if (ok == false) {
            break;
        }
        scc_lexer_tok_drop(&dummy);
    }
    scc_lexer_drop_ring(ring);
    scc_lexer_drop(&lexer);
    scc_sstream_drop(&sstream);
    if (ctx->need_keep_org_pos)
        result.loc = ctx->call_pos;
    return result;
}

static inline void scc_copy_expand(scc_pproc_expand_t *expand_ctx,
                                   scc_pproc_expand_t *copyed_ctx,
                                   scc_lexer_tok_ring_t *ring) {

    copyed_ctx->input = ring;
    copyed_ctx->expanded_set = expand_ctx->expanded_set;
    copyed_ctx->macro_table = expand_ctx->macro_table;
    copyed_ctx->need_rescan = false;
    copyed_ctx->need_parse_defined = expand_ctx->need_parse_defined;
    scc_vec_init(copyed_ctx->output);
}

void scc_pproc_expand_by_src(scc_pproc_macro_table_t *macro_table,
                             scc_lexer_tok_ring_t *input,
                             scc_lexer_tok_ring_t *output,
                             const scc_pproc_macro_t *macro,
                             cbool need_keep_org_pos) {
    scc_lexer_tok_vec_t expaned_buffer;
    scc_vec_init(expaned_buffer);

    int ok;
    scc_lexer_tok_t tok;
    scc_ring_next_consume(*input, tok, ok);
    if (macro->type == SCC_PP_MACRO_NONE || ok == false) {
        UNREACHABLE();
    } else if (macro->type == SCC_PP_MACRO_OBJECT) {
        scc_vec_push(expaned_buffer, tok);
    } else if (macro->type == SCC_PP_MACRO_FUNCTION) {
        scc_vec_push(expaned_buffer, tok);
        scc_pproc_parse_macro_arguments(input, &expaned_buffer, true);
    }
    while (1) {
        ok = scc_lexer_peek_non_blank(input, &tok);
        if (ok == false) {
            break;
        }
        if (tok.type == SCC_TOK_L_PAREN) {
            scc_pproc_parse_macro_arguments(input, &expaned_buffer, true);
        } else {
            break;
        }
    }

    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
    *output = scc_lexer_array_to_ring(&output_vec);
}

void scc_pproc_expand_by_vec(scc_pproc_macro_table_t *macro_table,
                             scc_lexer_tok_vec_t *input,
                             scc_lexer_tok_vec_t *output,
                             cbool need_parse_defined,
                             cbool need_keep_org_pos) {
    scc_pproc_expand_t ctx;
    scc_lexer_tok_ring_t ring = scc_lexer_array_to_ring(input);
    ctx.input = &ring;
    ctx.macro_table = macro_table;
    ctx.need_rescan = false;
    ctx.need_parse_defined = need_parse_defined;
    ctx.need_keep_org_pos = need_keep_org_pos;
    ctx.call_pos = scc_pos_create();
    scc_vec_init(ctx.output);
    scc_pproc_macro_table_t expanded_set;
    ctx.expanded_set = &expanded_set;

    scc_pproc_marco_table_init(ctx.expanded_set);
    scc_pproc_expand_macro(&ctx);
    *output = ctx.output;
    scc_ring_free(*ctx.input);
    scc_pproc_macro_table_drop(ctx.expanded_set);
}

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) {
        LOG_FATAL("Out of memory");
    }
    scc_pproc_macro_table_set(expand_ctx->expanded_set, expanded_macro);
}

static void enable(scc_pproc_expand_t *expand_ctx,
                   const scc_pproc_macro_t *macro) {
    scc_pproc_macro_table_remove(expand_ctx->expanded_set, &macro->name);
}

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;
}

static inline void
split_arguments(scc_pproc_macro_extened_params_t *splited_params,
                scc_lexer_tok_vec_t *raw_args, const scc_pproc_macro_t *macro) {
    scc_lexer_tok_vec_t args;
    scc_vec_init(args);

    int named_count = (int)scc_vec_size(macro->params);
    cbool is_variadic =
        (named_count > 0 &&
         scc_vec_at(macro->params, named_count - 1).type == SCC_TOK_ELLIPSIS);

    int depth = 0;

    scc_vec_foreach(*raw_args, i) {
        scc_lexer_tok_t *raw_arg = &scc_vec_at(*raw_args, i);
        if (raw_arg->type == SCC_TOK_L_PAREN) {
            depth++;
        } else if (raw_arg->type == SCC_TOK_R_PAREN) {
            depth--;
        }
        if (depth != 0 || raw_arg->type != SCC_TOK_COMMA ||
            (is_variadic &&
             (int)scc_vec_size(*splited_params) == named_count - 1)) {
            if (scc_vec_size(args) == 0 && raw_arg->type == SCC_TOK_BLANK) {
                scc_lexer_tok_drop(raw_arg);
            } else {
                scc_lexer_tok_t arg;
                scc_lexer_tok_move(&arg, raw_arg);
                scc_vec_push(args, arg);
            }
        } else {
            scc_lexer_tok_drop(raw_arg);
            if (scc_vec_size(args) &&
                scc_vec_at(args, scc_vec_size(args) - 1).type ==
                    SCC_TOK_BLANK) {
                scc_lexer_tok_drop(&scc_vec_pop(args));
            }
            scc_vec_push(*splited_params, args);
            scc_vec_init(args);
        }
    }
    scc_vec_free(*raw_args);

    if (scc_vec_size(args) &&
        scc_vec_at(args, scc_vec_size(args) - 1).type == SCC_TOK_BLANK) {
        scc_lexer_tok_drop(&scc_vec_pop(args));
    }

    scc_vec_push(*splited_params, args);
    if (is_variadic && (int)scc_vec_size(*splited_params) == named_count - 1) {
        scc_vec_init(args);
        scc_vec_push(*splited_params, args);
    }
}

static inline void
expand_arguments(scc_pproc_macro_extened_params_t *expanded_params,
                 scc_pproc_macro_extened_params_t *splited_params,
                 scc_pproc_expand_t *expand_ctx) {
    scc_vec_foreach(*splited_params, i) {
        scc_pproc_expand_t ctx;
        scc_lexer_tok_vec_t splite_param = scc_vec_at(*splited_params, i);
        scc_lexer_tok_vec_t expanded_param;
        scc_vec_init(expanded_param);
        scc_vec_foreach(splite_param, j) {
            scc_lexer_tok_t tok = scc_vec_at(splite_param, j);
            tok.lexeme = scc_cstring_copy(&tok.lexeme);
            scc_vec_push(expanded_param, tok);
        }
        scc_lexer_tok_ring_t ring = scc_lexer_array_to_ring(&expanded_param);
        scc_copy_expand(expand_ctx, &ctx, &ring);
        scc_pproc_expand_macro(&ctx);
        scc_ring_free(ring);
        scc_vec_push(*expanded_params, ctx.output);
    }
}

static inline void
expanded_params_free(scc_pproc_macro_extened_params_t *expanded_params) {
    scc_vec_foreach(*expanded_params, i) {
        scc_lexer_tok_vec_t expanded_param = scc_vec_at(*expanded_params, i);
        scc_vec_foreach(expanded_param, j) {
            scc_lexer_tok_t tok = scc_vec_at(expanded_param, j);
            scc_lexer_tok_drop(&tok);
        }
        scc_vec_free(expanded_param);
    }
    scc_vec_free(*expanded_params);
}

static void rescan(scc_pproc_expand_t *expand_ctx,
                   const scc_pproc_macro_t *macro,
                   scc_lexer_tok_vec_t *tok_buffer) {
    scc_pproc_expand_t rescan_ctx;

    scc_lexer_tok_ring_t ring = scc_lexer_array_to_ring(tok_buffer);
    scc_copy_expand(expand_ctx, &rescan_ctx, &ring);

    disable(expand_ctx, macro);
    scc_pproc_expand_macro(&rescan_ctx);
    enable(expand_ctx, macro);

    scc_vec_foreach(rescan_ctx.output, i) {
        scc_vec_push(expand_ctx->output, scc_vec_at(rescan_ctx.output, i));
    }

    if (scc_vec_size(expand_ctx->output) == 0) {
        goto RETURN;
    }

    scc_lexer_tok_t *end_tok =
        &scc_vec_at(expand_ctx->output, scc_vec_size(expand_ctx->output) - 1);

    if (scc_get_tok_subtype(end_tok->type) != SCC_TOK_SUBTYPE_IDENTIFIER) {
        goto RETURN;
    }

    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) {
        goto RETURN;
    }

    int ok = false;
    scc_lexer_tok_t tok;
    ok = scc_lexer_peek_non_blank(expand_ctx->input, &tok);
    if (ok && tok.type == SCC_TOK_L_PAREN) {
        scc_lexer_tok_vec_t expaned_buffer;
        scc_vec_init(expaned_buffer);
        scc_vec_push(expaned_buffer, scc_vec_pop(expand_ctx->output));
        scc_pproc_parse_macro_arguments(expand_ctx->input, &expaned_buffer,
                                        true);
        scc_lexer_tok_vec_t output = {0};
        scc_pproc_expand_by_vec(expand_ctx->macro_table, &expaned_buffer,
                                &output, expand_ctx->need_parse_defined,
                                expand_ctx->need_keep_org_pos);
        scc_vec_foreach(output, i) {
            scc_vec_push(expand_ctx->output, scc_vec_at(output, i));
        }
        scc_vec_free(output);
    }

RETURN:
    scc_ring_free(*rescan_ctx.input);
    scc_vec_free(rescan_ctx.output);
}

static int find_params(const scc_lexer_tok_t *tok,
                       const scc_pproc_macro_t *macro) {
    scc_vec_foreach(macro->params, j) {
        if (scc_cstring_cmp(&(tok->lexeme),
                            &(scc_vec_at(macro->params, j).lexeme)) == 0) {
            return j;
        }
    }
    return -1;
}
static inline int got_left_non_blank(int i,
                                     const scc_lexer_tok_vec_t *replaces) {
    int left_idx = i - 1;
    while (left_idx >= 0 &&
           scc_vec_at(*replaces, left_idx).type == SCC_TOK_BLANK) {
        left_idx--;
    }
    return left_idx;
}
static inline int got_right_non_blank(int i,
                                      const scc_lexer_tok_vec_t *replaces) {
    int right_idx = i + 1;
    while (right_idx < (int)scc_vec_size(*replaces) &&
           scc_vec_at(*replaces, right_idx).type == SCC_TOK_BLANK) {
        right_idx++;
    }
    return right_idx;
}

static void concact(scc_pproc_expand_t *ctx, scc_lexer_tok_vec_t *tok_buffer,
                    scc_lexer_tok_t *right, cbool gnu_va_arg_extend) {
    // ## contact
    int tok_buf_size = (int)scc_vec_size(*tok_buffer);
    int left_idx = got_left_non_blank(tok_buf_size, tok_buffer);

    scc_lexer_tok_t *left;
    if (left_idx < 0) {
        left = null;
        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;
        }
    }

    scc_lexer_tok_t concate_tok = concatenate_tokens(ctx, left, right);

    while (left_idx++ < tok_buf_size) {
        scc_lexer_tok_drop(&scc_vec_pop(*tok_buffer));
    }
    if (concate_tok.type == SCC_TOK_UNKNOWN) {
        LOG_FATAL("Invalid ## token");
    }
    if (concate_tok.type != SCC_TOK_EOF) {
        scc_vec_push(*tok_buffer, concate_tok);
    }
}

static inline void expand_function_macro(scc_pproc_expand_t *expand_ctx,
                                         const scc_pproc_macro_t *macro) {

    scc_lexer_tok_vec_t tok_buffer;
    scc_vec_init(tok_buffer);

    Assert(macro->type == SCC_PP_MACRO_FUNCTION);
    scc_lexer_tok_vec_t raw_args;
    scc_vec_init(raw_args);
    scc_pproc_parse_macro_arguments(expand_ctx->input, &raw_args, false);

    // collect, fill and expand arg
    scc_pproc_macro_extened_params_t splited_params;
    scc_vec_init(splited_params);
    split_arguments(&splited_params, &raw_args, macro);
    Assert(raw_args.cap == 0); // FIXME
    Assert(scc_vec_size(splited_params) >= scc_vec_size(macro->params));

    scc_pproc_macro_extened_params_t expanded_params;
    scc_vec_init(expanded_params);
    expand_arguments(&expanded_params, &splited_params, expand_ctx);
    Assert(scc_vec_size(expanded_params) >= scc_vec_size(macro->params));

    // replace
    scc_vec_foreach(macro->replaces, i) {
        scc_lexer_tok_t tok =
            scc_lexer_tok_copy(&scc_vec_at(macro->replaces, i));
        if (expand_ctx->need_keep_org_pos)
            tok.loc = expand_ctx->call_pos;
        if (tok.type == SCC_TOK_BLANK) {
            scc_cstring_free(&tok.lexeme);
            tok.lexeme = scc_cstring_from_cstr(" ");
            scc_vec_push(tok_buffer, tok);
            continue;
        }

        if (tok.type == SCC_TOK_SHARP) {
            // # stringify
            scc_lexer_tok_drop(&tok);
            int right_idx = got_right_non_blank(i, &macro->replaces);
            if (right_idx >= (int)macro->replaces.size) {
                LOG_WARN("generate empty stringify");
                scc_cstring_free(&tok.lexeme);
                tok.lexeme = scc_cstring_from_cstr("");
                scc_vec_push(tok_buffer, tok);
                break;
            }
            int j = find_params(&scc_vec_at(macro->replaces, right_idx), macro);
            Assert(j != -1 && j < (int)scc_vec_size(splited_params));

            tok =
                stringify_argument(expand_ctx, &scc_vec_at(splited_params, j));
            scc_vec_push(tok_buffer, tok);
            i = right_idx;
            continue;
        } else if (tok.type == SCC_TOK_SHARP_SHARP) {
            // ## contact
            scc_lexer_tok_drop(&tok);
            int right_idx = got_right_non_blank(i, &macro->replaces);

            scc_lexer_tok_t *right_tok;
            if (right_idx >= (int)scc_vec_size(macro->replaces)) {
                right_tok = null;
            } else {
                right_tok = &scc_vec_at(macro->replaces, right_idx);
            }

            int idx = find_params(right_tok, macro);
            scc_lexer_tok_vec_t right_vec;
            scc_vec_init(right_vec);
            if (idx != -1) {
                Assert(idx < (int)scc_vec_size(splited_params));
                scc_lexer_tok_vec_t *tok_vec = &scc_vec_at(splited_params, idx);
                scc_vec_foreach(*tok_vec, j) {
                    scc_vec_push(right_vec,
                                 scc_lexer_tok_copy(&scc_vec_at(*tok_vec, j)));
                }
            } else {
                scc_vec_push(right_vec, scc_lexer_tok_copy(right_tok));
            }

            scc_lexer_tok_t *right =
                scc_vec_size(right_vec) ? &scc_vec_at(right_vec, 0) : null;

            // GNU ## extention
            if (scc_strcmp(scc_cstring_as_cstr(&(right_tok->lexeme)),
                           "__VA_ARGS__") == 0) {
                if (scc_vec_size(right_vec) == 0) {
                    concact(expand_ctx, &tok_buffer, right, true);
                } else {
                    continue;
                }
            } else {
                concact(expand_ctx, &tok_buffer, right, false);
            }

            scc_vec_foreach(right_vec, j) {
                if (j == 0) {
                    scc_lexer_tok_drop(&scc_vec_at(right_vec, j));
                    continue;
                }
                scc_lexer_tok_t tok = {0};
                scc_lexer_tok_move(&tok, &scc_vec_at(right_vec, j));
                scc_lexer_tok_drop(&scc_vec_at(right_vec, j));
                scc_vec_push(tok_buffer, tok);
            }
            scc_vec_free(right_vec);

            i = right_idx;
            continue;
        } else {
            int j = find_params(&tok, macro);
            if (j != -1) {
                Assert(j < (int)scc_vec_size(expanded_params));
                scc_lexer_tok_vec_t expanded_param =
                    scc_vec_at(expanded_params, j);
                scc_lexer_tok_drop(&tok);
                scc_vec_foreach(expanded_param, k) {
                    tok = scc_lexer_tok_copy(&scc_vec_at(expanded_param, k));
                    scc_vec_push(tok_buffer, tok);
                }
                continue;
            }
        }
        scc_vec_push(tok_buffer, tok);
    }
    expanded_params_free(&splited_params);
    expanded_params_free(&expanded_params);

    rescan(expand_ctx, macro, &tok_buffer);
    Assert(tok_buffer.cap == 0); // FIXME
}

static inline void expand_object_macro(scc_pproc_expand_t *expand_ctx,
                                       const scc_pproc_macro_t *macro) {
    scc_lexer_tok_vec_t tok_buffer;
    scc_vec_init(tok_buffer);

    scc_vec_foreach(macro->replaces, i) {
        scc_lexer_tok_t tok =
            scc_lexer_tok_copy(&scc_vec_at(macro->replaces, i));
        if (expand_ctx->need_keep_org_pos)
            tok.loc = expand_ctx->call_pos;
        if (tok.type == SCC_TOK_BLANK) {
            // FIXME using function to warpper it
            scc_cstring_free(&tok.lexeme);
            tok.lexeme = scc_cstring_from_cstr(" ");
        } else if (tok.type == SCC_TOK_SHARP_SHARP) {
            // ## contact
            scc_lexer_tok_drop(&tok);
            int right_idx = got_right_non_blank(i, &macro->replaces);

            scc_lexer_tok_t *right;
            if (right_idx >= (int)scc_vec_size(macro->replaces)) {
                right = null;
            } else {
                right = &scc_vec_at(macro->replaces, right_idx);
            }

            concact(expand_ctx, &tok_buffer, right, false);
            i = right_idx;
            continue;
        }
        scc_vec_push(tok_buffer, tok);
    }

    rescan(expand_ctx, macro, &tok_buffer);
}

static cbool parse_defined(scc_pproc_expand_t *expand_ctx, scc_pos_t *tok_pos) {
    scc_lexer_tok_t next_tok = {0};
    if (scc_lexer_next_non_blank(expand_ctx->input, &next_tok) == false) {
        SCC_ERROR(*tok_pos, "Unexpected before defined EOF");
    }
    if (next_tok.type == SCC_TOK_L_PAREN) {
        scc_lexer_tok_drop(&next_tok);
        scc_lexer_next_non_blank(expand_ctx->input, &next_tok);
        if (scc_get_tok_subtype(next_tok.type) != SCC_TOK_SUBTYPE_IDENTIFIER) {
            SCC_ERROR(next_tok.loc, "Expected identifier before defined");
            scc_lexer_tok_drop(&next_tok);
        }

        if (scc_pproc_macro_table_get(expand_ctx->macro_table,
                                      &next_tok.lexeme) == null) {
            scc_lexer_tok_drop(&next_tok);
            scc_lexer_gen_number_false(&next_tok);
        } else {
            scc_lexer_tok_drop(&next_tok);
            scc_lexer_gen_number_true(&next_tok);
        }
        scc_vec_push(expand_ctx->output, next_tok);

        if (scc_lexer_next_non_blank(expand_ctx->input, &next_tok)) {
            if (next_tok.type == SCC_TOK_R_PAREN) {
                scc_lexer_tok_drop(&next_tok);
                return false;
            } else {
                SCC_ERROR(next_tok.loc, "Expected ')'");
                scc_lexer_tok_drop(&next_tok);
            }
        }
    } 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) {
            scc_lexer_tok_drop(&next_tok);
            scc_lexer_gen_number_false(&next_tok);
        } else {
            scc_lexer_tok_drop(&next_tok);
            scc_lexer_gen_number_true(&next_tok);
        }
        scc_vec_push(expand_ctx->output, next_tok);
    }
    return true;
}

void scc_pproc_expand_macro(scc_pproc_expand_t *expand_ctx) {
    int ok;
    scc_lexer_tok_t tok;
    while (1) {
        scc_ring_next_consume(*expand_ctx->input, tok, ok);
        if (!ok) {
            return;
        }
        if (scc_get_tok_subtype(tok.type) != SCC_TOK_SUBTYPE_IDENTIFIER) {
            scc_vec_push(expand_ctx->output, tok);
            continue;
        }

        if (expand_ctx->need_parse_defined &&
            scc_strcmp(scc_cstring_as_cstr(&tok.lexeme), "defined") == 0) {
            scc_pos_t pos = tok.loc;
            scc_lexer_tok_drop(&tok);
            if (parse_defined(expand_ctx, &pos)) {
                continue;
            } else {
                break;
            }
        }

        // maybe expanded
        scc_pproc_macro_t *macro =
            scc_pproc_macro_table_get(expand_ctx->macro_table, &tok.lexeme);

        if (macro == null || need_skip(expand_ctx, macro)) {
            // FIXME maybe keyword is error or don't parse c keyword or number
            // 这个地方不太清楚正确的原因
            tok.type = SCC_TOK_DISABLED;
            scc_vec_push(expand_ctx->output, tok);
            continue;
        }
        expand_ctx->need_rescan = true;

        expand_ctx->call_pos = tok.loc;
        if (macro->type == SCC_PP_MACRO_OBJECT) {
            scc_lexer_tok_drop(&tok);
            expand_object_macro(expand_ctx, macro);
        } else if (macro->type == SCC_PP_MACRO_FUNCTION) {
            scc_lexer_tok_t expect_tok;
            scc_ring_peek(*expand_ctx->input, expect_tok, ok);
            if (ok == false || expect_tok.type != SCC_TOK_L_PAREN) {
                scc_vec_push(expand_ctx->output, tok);
                continue;
            }

            scc_lexer_tok_drop(&tok);
            expand_function_macro(expand_ctx, macro);
        } else {
            UNREACHABLE();
        }
    }
}