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Re: evaluate to True?

• To: mathgroup at smc.vnet.net
• Subject: [mg125948] Re: evaluate to True?
• From: A Retey <awnl at gmx-topmail.de>
• Date: Mon, 9 Apr 2012 05:32:34 -0400 (EDT)
• Delivered-to: l-mathgroup@mail-archive0.wolfram.com
• References: <201204061001.GAA23045@smc.vnet.net> <CAEtRDSfexgBvoLTpXVPv=6B7m_CsNwqhUAWQBvnj4JMimsN-Sg@mail.gmail.com> <jlp3c2$17v$1@smc.vnet.net>

Hi,

> The misinterpretation of the function due to the name can be the cause
> of severe bugs as seen
> in message . Maybe a name like MatchQ would be more
> appropriate for future versions
> of Mathematica.

MatchQ already exists and does something slightly different. And MemberQ 
has been existing for many versions and probably will never be changed 
-- too much existing code would be broken.

I don't think that the name is problematic at all as there are many 
functions in Mathematica that use patterns in a similar way (e.g. 
Position, Cases, Collect...), so it doesn't really come as a surprise 
that MemberQ behaves as it does. By using patterns these functions 
become a lot more powerful so many users wouldn't see such a limitation 
as an advantage...

albert

• References:
  • Why does ModuleQ[{0,1,2}, expr_] evaluate to True?
    • From: Christoph Lhotka <christoph.lhotka@fundp.ac.be>