Pointer

The need

In Cobol 85 pointers, cannot be incremented or decremented by a numeric variable (like in C for example).

The solution

TypeCobol allow you to use the syntax :

SET MyPointer UP BY n
SET MyPointer UP BY 1
SET MyPointer DOWN BY n
SET MyPointer DOWN BY 1

Where:

• MyPointer is a pointer
• n is a numeric variable

Code generation

If a pointer is used that way, the code generation must add a redefines to the pointer like this:

01 MyPointer pointer.
01 MyPointer-HASH redefines MyPointer pic 9(05) comp-5.

Detailled rules

• POINTER_SET_UP_BY standard pointer of Cobol 85 declared in level 01 to 49 can be use in instruction SET UP BY and SET DOWN BY like index.
  • Forbird this syntax for pointer declared in level 77
• POINTER_CGEN_DECLARATION if a pointer is used in a SET UP/DOWN BY, then it's declaration is redefined.
  • The name of the redefines, is the 22 first characters of the pointer followed by a hash of 8 characters of the unique name of the pointer. This name is named redefinedPtrName.
  • The picture clause is pic 9(05) comp-5
• POINTER_CGEN_USAGE the instruction SET ptr UP BY n is translated to ADD n to redefinedPtrName