Ada与Cobol的接口

Question

我正在研究Ada-> COBOL接口，我想知道是否有任何方法可以将文件写入Cobol默认，而不需要编写cobol代码，因为我想使用Cobol的一些规则来编写文件，但想知道如何在Ada中直接执行此操作。

例如，要读取具有cobol结构的文件，我可以使用use that：

with Interfaces.COBOL;
with COBOL_Sequential_IO; -- Assumed to be supplied by implementation
procedure Test_External_Formats is
112
   -- Using data created by a COBOL program
   -- Assume that a COBOL program has created a sequential file with
   --  the following record structure, and that we need to
   --  process the records in an Ada program
   --  01 EMPLOYEE-RECORD
   --     05 NAME    PIC X(20).
   --     05 SSN     PIC X(9).
   --     05 SALARY  PIC 99999V99 USAGE COMP.
   --     05 ADJUST  PIC S999V999 SIGN LEADING SEPARATE.
   -- The COMP data is binary (32 bits), high-order byte first
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   package COBOL renames Interfaces.COBOL;
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   type Salary_Type      is delta 0.01  digits 7;
   type Adjustments_Type is delta 0.001 digits 6;
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   type COBOL_Employee_Record_Type is  -- External representation
      record
         Name    : COBOL.Alphanumeric(1..20);
         SSN     : COBOL.Alphanumeric(1..9);
         Salary  : COBOL.Byte_Array(1..4);
         Adjust  : COBOL.Numeric(1..7);  -- Sign and 6 digits
      end record;
   pragma Convention (COBOL, COBOL_Employee_Record_Type);
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   package COBOL_Employee_IO is
      new COBOL_Sequential_IO(COBOL_Employee_Record_Type);
   use COBOL_Employee_IO;
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   COBOL_File : File_Type;
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   type Ada_Employee_Record_Type is  -- Internal representation
      record
         Name    : String(1..20);
         SSN     : String(1..9);
         Salary  : Salary_Type;
         Adjust  : Adjustments_Type;
      end record;
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   COBOL_Record : COBOL_Employee_Record_Type;
   Ada_Record   : Ada_Employee_Record_Type;
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   package Salary_Conversions is
      new COBOL.Decimal_Conversions(Salary_Type);
   use Salary_Conversions;
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   package Adjustments_Conversions is
      new COBOL.Decimal_Conversions(Adjustments_Type);
   use Adjustments_Conversions;
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begin
   Open (COBOL_File, Name => "Some_File");
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   loop
     Read (COBOL_File, COBOL_Record);
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     Ada_Record.Name := To_Ada(COBOL_Record.Name);
     Ada_Record.SSN  := To_Ada(COBOL_Record.SSN);
     Ada_Record.Salary :=
        To_Decimal(COBOL_Record.Salary, COBOL.High_Order_First);
     Ada_Record.Adjust :=
        To_Decimal(COBOL_Record.Adjust, COBOL.Leading_Separate);
     ... -- Process Ada_Record
   end loop;
exception
   when End_Error => ...
end Test_External_Formats;

Put，我不知道如何编写cobol结构的文件，在文档中，我找不到方法；http://www-users.cs.york.ac.uk/~andy/lrm95/b_04.htm

例如，如果我在Cobol中有这个结构(基于这个示例：http://www.csis.ul.ie/cobol/examples/Sort/MaleSort.htm；http://www.csis.ul.ie/cobol/examples/SeqIns/STUDENTS.DAT )

FILE SECTION.
FD StudentFile.
01 StudentRec      PIC X(30).
   88 EndOfFile    VALUE HIGH-VALUES.

FD MaleStudentFile.
01 MaleStudentRec  PIC X(30).

SD WorkFile.
01 WorkRec.
   02 FILLER             PIC 9(7).
   02 WStudentName       PIC X(10).
   02 FILLER             PIC X(12).
   02 WGender            PIC X.
      88 MaleStudent     VALUE "M".

如何使用Cobol接口在Ada中编写程序来编写此结构？

Answer 1

身体上的思考。也就是说，输出文件的格式是什么？在设计文件时，是否在Cobol或Ada中创建该文件并不是一个直接的问题。

让我们假设Cobol Workrec描述了文件的格式。你想写一个Ada程序来调用cobol子例程来物理地写文件吗？或者你想使用一个Cobol程序来写这个文件？或者你想要一个Ada程序来写一个smae格式的文件作为Workrec?？您的选择取决于您的客户的要求。