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From: =?utf-8?Q?Yannick_Duch=C3=AAne_=28Hibou57?=
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Newsgroups: comp.lang.ada
Subject: Re: Silly and stupid post-condition or not ?
Date: Mon, 06 Feb 2012 05:56:40 +0100
Organization: Ada @ Home
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Date: 2012-02-06T05:56:40+01:00
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Le Sun, 05 Feb 2012 16:16:26 +0100, Robert A Duff  =

<bobduff@shell01.theworld.com> a =C3=A9crit:
> By the way, I find that when I (at first) think I want a
> pre/post, it's usually better expressed as a subtype predicate.
> My favorite new feature of Ada 2012.
>
> - Bob

Seems nice, but given this=E2=80=A6

    subtype Image_Type is String
       with Static_Predicate =3D> Image_Type'Length in Length_Type;

    function Image (Instance : Instance_Type) return Image_Type
       with Post =3D>
         (Parsed (Image'Result).Status =3D Parsed) and
         (Parsed (Image'Result).Instance =3D Instance);
       -- Result can always be successfully parsed and the resulting
       -- instance is always equal to the one whose image is returned.

=E2=80=A6how do I move Image's Post predicate to an Image_Type's dynamic=
 predicate  =

? I could not figure the syntax nor if it's at least possible.

-- =

=E2=80=9CSyntactic sugar causes cancer of the semi-colons.=E2=80=9D [1]
=E2=80=9CStructured Programming supports the law of the excluded muddle.=
=E2=80=9D [1]
[1]: Epigrams on Programming =E2=80=94 Alan J. =E2=80=94 P. Yale Univers=
ity