From: "Jürgen Strobel" <strobel@...>
Date: 2006-08-23T09:33:01+09:00
Subject: Re: Enumerable#all? and empty arrays

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On Thu, Aug 10, 2006 at 08:55:12AM +0900, Just Another Victim of the Ambien=
t Morality wrote:
>=20
> "Andre Nathan" <andre@digirati.com.br> wrote in message=20
> news:1155141696.24603.43.camel@andre.mz.digirati.com.br...
> > Hello
> >
> > I found this to be somewhat amusing:
> >
> >>> a =3D []
> > =3D> []
> >>> a.all?
> > =3D> true
> >>> a.all? { |i| i =3D=3D 10 }
> > =3D> true
> >
> > Is there any reasoning for Enumerable#all? to always return true for
> > empty arrays?
>=20
>     It's mathematically consistent.
>=20
>     You may be surprised to hear this but mathematicians are generally=20
> optimists.  Thus, if a condition is "vacuously satisfied," then we genera=
lly=20
> say the condition is true...

unless mathematician.is_an :intuitionist  # (pretty rare)

Sorry I couldn't resist=20
-J=FCrgen

--=20
 The box said it requires Windows 95 or better so I installed Linux

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