From: Simon Wright <simon@pushface.org>
Subject: Re: Trouble cutting loops with SPARK. Advice?
Date: Sun, 07 Mar 2010 11:20:58 +0000
Date: 2010-03-07T11:20:58+00:00 [thread overview]
Message-ID: <m2y6i4s7hh.fsf@pushface.org> (raw)
In-Reply-To: 484e7806-9242-4c20-a057-cbc34fd67f03@g28g2000yqh.googlegroups.com
Phil Thornley <phil.jpthornley@googlemail.com> writes:
> The problem is that the value of the variables that provide the loop
> bounds (in your code the variable Characters_To_Copy) can be changed
> within the loop, so any reference to Characters_To_Copy within an
> assertion in the loop means the *current* value, not the value that
> defined the loop bound.
Would it have helped if Peter had said, instead of
Characters_To_Copy : Line_Size_Type;
begin
Result.Text := Line_Type'(others => ' ');
if Line'Length > Max_Line_Length then
Characters_To_Copy := Max_Line_Length;
else
Characters_To_Copy := Line'Length;
end if;
this:
Characters_To_Copy : constant Line_Size_Type
:= Line_Size_Type'Min (Line'Length, Max_Line_Length);
begin
Result.Text := Line_Type'(others => ' ');
And I'm sure one could eliminate the loop by proper slicing. Of course,
that would reduce the SPARK learning experience ...
next prev parent reply other threads:[~2010-03-07 11:20 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-06 20:33 Trouble cutting loops with SPARK. Advice? Peter C. Chapin
2010-03-07 10:22 ` Phil Thornley
2010-03-07 11:04 ` Peter C. Chapin
2010-03-07 11:41 ` Phil Thornley
2010-03-07 11:20 ` Simon Wright [this message]
2010-03-07 11:43 ` Phil Thornley
2010-03-07 16:27 ` Simon Wright
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