Re: How to write "Hello" to a text file without a line terminator

[AdaMagica <christ-usch.grein@t-online.de>]

Am Sonntag, 14. August 2016 10:30:15 UTC+2 schrieb Simon Wright:
> Come to think of it, what would the use case be for instantiating
> Sequential (or Direct) IO with an unconstrained type? they both have
> only procedural forms for Read, so how could you ever retrieve a value?

No problem for a type like this (without the defaulted discriminant, you'll have indeed a problem, as for strings):

  type Disc is (A, B, C, D);
  type Rec (X: Disc := A) is record
    case X is
      when A => I: Integer;
      when B => F: Float;
      when C => B: Boolean;
      when D => null;
    end case;
  end record;

  package Req_Sequential_IO is new Ada.Sequential_IO (Rec);
  use Req_Sequential_IO;
  
  procedure Create is
    f:file_Type;
  begin
    create(f,out_file,"Rec");
    Write (f, (A, 42));
    Write (f, (C, False));
    Write (f, (X=>D));
    write (f, (B, -42.0));
    close(f);
  end Create;

  procedure Read is
    f:file_Type;
    R: Rec;
  begin
    open(f,in_file,"Rec");
    loop
      Read(f,R);
      exit when End_of_File(f);
    end loop;
    close(f);
  end Read;