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OneIdentity

• To: mathgroup at smc.vnet.net
• Subject: [mg103478] OneIdentity
• From: Chris Osborn <chrisosb at gmail.com>
• Date: Wed, 23 Sep 2009 23:52:05 -0400 (EDT)

I do not understand why I get "False" instead of "True" here:


In[773]:= ClearAll[key];
SetAttributes[key, OneIdentity];

MatchQ[13, key[_]]

Out[775]= False


According to the docs:

OneIdentity
is an attribute that can be assigned to a symbol f to indicate that f
[x], f[f[x]], etc. are all equivalent to x for the purpose of pattern
matching.


Thanks in advance,
Chris

• Follow-Ups:
  • Re: OneIdentity
    • From: "Kurt TeKolste" <tekolste@fastmail.us>
  • Re: OneIdentity
    • From: Andrzej Kozlowski <akoz@mimuw.edu.pl>