Constant Expression Expected Error when Initializing Array of Records

Question

I am facing an issue while trying to initialize a constant array of records in Delphi. Here's a simplified version of my code:

  TParameterList = record
    Parm_Name: string;
    Parm_Unit: string;
    IsRequired: Boolean;
    Default_Value: String;
    ParmV: Integer;
    Value_Options: TArray<String>;
  end;

const
 IP_Options: TArray<String> =['Option 1','Option 2','Option 3'];

const
  Cables_Parms: array[0..4] of TParameterList = (
    (Parm_Name: 'Insulation'; Parm_Unit: 'N/A'; IsRequired: True; Value_Options: IP_Options),
    // Other entries...
  );

However, I am encountering the error

Constant expression expected

specifically at the line where I try to initialize Value_Options with IP_Options. I would appreciate any insights into what might be causing this issue and how I can resolve it.

Answer 1

A dynamic array constant cannot be used in a constant expression:

type
  TTest = record
    a: Integer;
    b: TArray<Integer>;
  end;

const
  Arr: TArray<Integer> = [1, 2, 3];

  Test: TTest = (a: 394; b: Arr);       // [dcc32 Error] E2026 Constant expression expected

However, you can use a dynamic array literal in such a context:

type
  TTest = record
    a: Integer;
    b: TArray<Integer>;
  end;

const
  Test: TTest = (a: 394; b: [1, 2, 3]); // compiles

Obviously, this is not exactly what you may want, but it may be good enough.