RPG Cafe: Fall 2025: Define a variable like an enumeration

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Fall 2025: Define a variable like an enumeration

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• An enumeration can be defined with a data type.

            dcl-enum colorCodes int(3) qualified;
               blue 1;
               green 2;
               yellow 3;
             end-enum;
  

• Use the DFT keyword to identify one of the constants as the default value for the data type. This is the CLEAR value and the default initialization value.

            dcl-enum colorCodes int(3) qualified;
               blue 1;
               green 2;
               yellow 3;
               no_color -1 dft;
             end-enum;
  

• A variable, prototyped parameter, or return value can be defined like the typed enumeration. Field color is initialized to the default colorCodes.no_color (-1).

            dcl-s color like(colorCodes);
            dcl-s my_favourite_color like(colorCodes) inz(colorCodes.blue);
            dcl-s other_num int(3);
  
            dcl-pr my_proc;
               dcl-pi *n;
                  p1 like(colorCodes) const;
                  p2 like(colorCodes) const options(*exact);
               end-pi;
            end-pr;
  
  

• The values in the enumeration are the only valid values for the variable, parameter, or RETURN operation.
• The compiler places some restrictions on the values you can use with a variable, parameter, or return value defined like an enumeration. For example, you can't assign a literal value even if it is one of the values in the enumeration. Instead, you use the named constants from the enumeration. You can also use another variable defined like the enumeration.
• See https://www.ibm.com/docs/en/ssw_ibm_i_76/rzasd/typedenums.htm for complete information about the restrictions.

•           color = 3;                    // Error, even though this is the same as colorCodes.yellow
            color = colorCodes.yellow;    // Ok, this is a constant in the enumeration
            color = other_num;            // Error, even though other_num has the same data type, int(3)
            color = my_favourite_color;   // Ok, my_favourite_color is also defined like the enum
            my_proc (colorCodes.red       // Ok, the parameter is a constant in the enumeration
                  :  my_favourite_color); // Ok, the parameter is defined like the enumeration
  

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