GnuCOBOL平凡的“回波”函数

Question

如何为字符串处理创建X任意长度函数？琐碎(在其他语言中)“回显回复”做了一些意想不到的事情。文档、开放资源和常见问题解答( FAQ https://open-cobol.sourceforge.io/faq/index.html#id362 )都没有帮助。

   IDENTIFICATION DIVISION.
   PROGRAM-ID. stdtest.
   ENVIRONMENT DIVISION.
   CONFIGURATION SECTION.
   REPOSITORY.
       FUNCTION ALL INTRINSIC
       FUNCTION REPLY.
   DATA DIVISION.
   WORKING-STORAGE SECTION.
       01 tst BINARY-SHORT UNSIGNED.
       01 expected PIC S9(6)V9(4) USAGE COMP.
       01 argA PIC S9(6)V9(4) USAGE COMP.
       01 argB PIC S9(6)V9(4) USAGE COMP.
   PROCEDURE DIVISION.
       *> must print whole string instead of first 8 chars
       DISPLAY FUNCTION REPLY("The quick brown fox jumps over the lazy dog").
       STOP RUN.
   END PROGRAM stdtest.

   IDENTIFICATION DIVISION.
   FUNCTION-ID. REPLY.
   ENVIRONMENT DIVISION.
   CONFIGURATION SECTION.
   REPOSITORY.
       FUNCTION ALL INTRINSIC.
   DATA DIVISION.
   LINKAGE SECTION.
       01 argument PIC X ANY LENGTH.
       01 result.
           05 argument-pointer USAGE POINTER.
   PROCEDURE DIVISION USING BY REFERENCE argument RETURNING result.
       *> https://open-cobol.sourceforge.io/faq/index.html#id362
       MOVE argument TO result.
   END FUNCTION REPLY.

Answer 1

您的示例结果是8个字符，因为返回组(在您的机器上)有8个字节长(因为它下面的POINTER )。它编译时没有错误，因为您只引用组项，它是隐含的字母数字(-group)-item(如果添加USAGE NATIONAL，则为国家组项)。

使用(最近)“标准”COBOL的方法是可变长度的RETURNING项。

该标准为函数提供的选项是DYNAMIC LENGTH (理想版本，但GnuCOBOL尚未支持)或足够大到足以容纳数据的可变长度组(OCCURS 0 TO ... DEPENDING ON)。

以下示例应该可以工作(但是会导致内部码元错误，应该用即将到来的3.1rc1修复)：

       IDENTIFICATION DIVISION.
       FUNCTION-ID. REPLY.
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       77 arg-len   USAGE BINARY-LONG.
       LINKAGE SECTION.
       01 argument  PIC X ANY LENGTH.
       01 result.
          05 filler PIC X OCCURS 0 to 99999 DEPENDING ON arg-len.
       PROCEDURE DIVISION USING BY REFERENCE argument RETURNING result.
           MOVE FUNCTION LENGTH (argument) TO arg-len
           MOVE argument TO result.
       END FUNCTION REPLY.

注意:您可以在GnuCOBOL问题跟踪器中找到bug报告和修补程序，作为#641。