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From: =?UTF-8?Q?Bj=c3=b6rn_Lundin?= <b.f.lundin@gmail.com>
Newsgroups: comp.lang.ada
Subject: Re: Community Input for the Maintenance and Revision of the Ada
 Programming Language
Date: Fri, 1 Sep 2017 16:11:22 +0200
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Xref: news.eternal-september.org comp.lang.ada:47877
Date: 2017-09-01T16:11:22+02:00
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On 2017-08-03 07:45, Randy Brukardt wrote:

> WG 9 requests the Ada community to submit enhancements to be considered for 
> inclusion in the next revision of Ada. 

Hi!
I sometimes find the need to auto generate code from some kind of
description.
It would help quite a bit if there was a way to
* iterate over fields in a record
* query a field of its properties, like type, length if applicable


  type Data_Type is new Table_Utils.Root_Table_Type with record
    Bldid : Integer_4 := 0 ; -- Primary Key
    Bldsta : Integer_4 := 0 ;
    Bldtyp : Integer_4 := 0 ;
    Bldwei : Float_8 := 0.0 ;
    Blochei : Integer_4 := 0 ;
    Bwmsid : String(1 .. 35) := (others => ' ') ; -- non unique index 2
    Bwmsldid : Integer_4 := 0 ;
    Xlocnam : String(1 .. 20) := (others => ' ') ; -- non unique index 3
    Bcrets : Time_Type := Time_Type_First ;
    Bcartyp : Integer_4 := 0 ;
    Bcawei : Float_8 := 0.0 ;
    Bwanzone : Integer_4 := 0 ;
    Pulv : String(1 .. 3) := (others => ' ') ;
    Ixxlupd : String(1 .. 12) := (others => ' ') ;
    Ixxluts : Time_Type := Time_Type_First ;
  end record;

  Load : Data_Type;


Here I'd like to do

for Field of Load'Fields loop
  case Field.Data_Type is
    when Integer_4 =>
      Text_io.Put_Line(Integer_4'Image(Field));
    when Float_8   =>
      Text_io.Put_Line(Formatted_Float_8.To_String(Field));
    when Time_Type =>
      Text_io.Put_Line(Cal.To_Iso_String(Field));
    when String=>
      Text_io.Put_Line(Field & "-" & Field'Length'Img);
    when others =>
      raise Not_Supported_Data_Type & Field.name;
  end case
end loop;

There is likely more info that would be nice to have, but
The mentioned above would be great.


-- 
--
Björn