From: Maciej Sobczak <see.my.homepage@gmail.com>
Subject: Spark_IO: improving with postconditions?
Date: Wed, 26 Aug 2009 01:57:05 -0700 (PDT)
Date: 2009-08-26T01:57:05-07:00 [thread overview]
Message-ID: <a6cc46c0-eab3-4a77-b3dd-ee870d85c936@18g2000yqa.googlegroups.com> (raw)
The Spark_IO package defines several procedures that "return" string
values by filling the given String object and the end-of-sequence
index value. This end-of-sequence parameter is consistently defined
as:
Stop : out Natural
One example of such a function is:
procedure Get_Line (File : in File_Type;
Item : out String;
Stop : out Natural);
--# global in out Inputs;
--# derives Inputs,
--# Item,
--# Stop from Inputs, File;
--# declare delay;
Wouldn't it be good to enhance this specification with additional:
--# post Stop <= Item'Last;
It would save the caller from one redundant check if the Stop value is
ever used again as index into the returned string value.
--
Maciej Sobczak * www.msobczak.com * www.inspirel.com
Database Access Library for Ada: www.inspirel.com/soci-ada
next reply other threads:[~2009-08-26 8:57 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-08-26 8:57 Maciej Sobczak [this message]
2009-08-26 9:23 ` Spark_IO: improving with postconditions? Georg Bauhaus
2009-08-26 14:47 ` xavier grave
2009-08-26 15:47 ` Georg Bauhaus
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