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Re: Pattern Syntax for Alternate Heads with Default Value

• To: mathgroup at smc.vnet.net
• Subject: [mg125841] Re: Pattern Syntax for Alternate Heads with Default Value
• From: "djmpark" <djmpark at comcast.net>
• Date: Thu, 5 Apr 2012 05:43:58 -0400 (EDT)
• Delivered-to: l-mathgroup@mail-archive0.wolfram.com
• References: <10944665.56141.1333528611484.JavaMail.root@m06>

f[x : (_Real | _Integer) : 2.5] := x^2 

The general form is name:pattern:default.


David Park
djmpark at comcast.net 
http://home.comcast.net/~djmpark/index.html 


From: Ben [mailto:benp84 at gmail.com] 

I'm trying to build a unary function which accepts only arguments with two
possible heads and has a default value.  That is, something like the
following, except that this doesn't work.  Anyone know how to do this
correctly?

f[(x_Real | x_Integer) : 2.5] := x^2;
where f[3] = 9
and f[1.5] = 2.25
and f[] = 6.25