Re: Why these "Drop" parameters? (was: variable lenght strings)

["Randy Brukardt" <randy@rrsoftware.com>]

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I think it is a typo for the Bounded_Slice and Unbounded_Slice routines;
nowhere can I find any description of what it means (the text description of
these functions never mentions "Drop"). Nor do any of the meeting minutes
that I checked.

Could you submit your comment to Ada-Comment (e-mail it to
ada-comment@ada-auth.org)? We need to get it on the record so this can be
fixed.

                Randy Brukardt
                ARG Editor.

"Bj�rn Persson" <spam-away@nowhere.nil> wrote in message
news:lESed.6963$d5.58967@newsb.telia.net...
Martin Dowie wrote:

> Being added in Ada2005, see Ada.Text_IO.Unbounded_IO in
> http://www.ada-auth.org/cgi-bin/cvsweb.cgi/AIs/AI-00301.TXT?rev=1.12

Reading that file I see these declarations:

procedure Set_Bounded_String
    (Target :    out Bounded_String;
     Source : in     String;
     Drop   : in     Truncation := Error);

function Bounded_Slice
    (Source : in Bounded_String;
     Low    : in Positive;
     High   : in Natural;
     Drop   : in Truncation := Error)
        return Bounded_String;

procedure Bounded_Slice
    (Source : in     Bounded_String;
     Target :    out Bounded_String;
     Low    : in     Positive;
     High   : in     Natural;
     Drop   : in     Truncation := Error);

procedure Set_Unbounded_String
    (Target :    out Unbounded_String;
     Source : in     String;
     Drop   : in     Truncation := Error);

function Unbounded_Slice
    (Source : in Unbounded_String;
     Low    : in Positive;
     High   : in Natural;
     Drop   : in Truncation := Error)
        return Unbounded_String;

procedure Unbounded_Slice
    (Source : in     Unbounded_String;
     Target :    out Unbounded_String;
     Low    : in     Positive;
     High   : in     Natural;
     Drop   : in     Truncation := Error);

For Set_Bounded_String it is quite obvious that Drop specifies what
should happen if Source is longer than the maximum length of Target, but
can anyone explain what all the other "Drop" parameters are for?

In the case of Bounded_Slice, shouldn't a slice of Source always fit in
Target? Aren't they the same type, with the same max length?

Unbounded strings are supposed to be unbounded. Their only limit should
be the available memory, no? So, are the "Drop" parameters there meant
as a way to avoid Storage_Error?

--
Bj�rn Persson                              PGP key A88682FD
                    omb jor ers @sv ge.
                    r o.b n.p son eri nu