Re: Re: Function, Command, Operator, Object...etc.

• To: mathgroup at smc.vnet.net
• Subject: [mg61425] Re: [mg61422] Re: [mg61350] Function, Command, Operator, Object...etc.
• From: Andrzej Kozlowski <akoz at mimuw.edu.pl>
• Date: Wed, 19 Oct 2005 02:16:04 -0400 (EDT)
• References: <200510160418.AAA22613@smc.vnet.net> <200510180645.CAA11327@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

```It certainly is.

FullForm[x_]

Pattern[x,Blank[]]

However, there is one thing here that is a bit strange. This:

In[14]:=
FullForm[_]

Out[14]//FullForm=
Blank[]

has head Blank but is in fact a pattern. But still, it certainly is
an expression. There only things that are not expressions are special
constructs such as  !!filename  (show file) and a few others.

Andrzej Kozlowski

On 18 Oct 2005, at 15:45, Chris Chiasson wrote:

> Maybe I am wrong, but pretty much every expression has a head and zero
> or more slots. That's it.
>
> I wonder if a pattern is an expression...
>
> On 10/16/05, Steven T. Hatton <hattons at globalsymmetry.com> wrote:
>
>> Section 2.1.2 of The Mathematica Book for 5.2 discusses different
>> ways to
>> interpret parts of expressions.  The examples given are "Function,
>> Command,
>> Operator, Head and Object type."  Do these terms have any meaning
>> within
>> the Mathematica language, or are these purely conceptual ideas
>> intended to
>> aid the user in understanding the language?  Are these terms given
>> formal
>> definitions as regards their meaning when used to discuss
>> Mathematica?  If
>> so, where might I find these definitions?
>> --
>> "Philosophy is written in this grand book, The Universe. ... But
>> the book
>> cannot be understood unless one first learns to comprehend the
>> language...
>> in which it is written. It is written in the language of
>> mathematics, ...;
>> without which wanders about in a dark labyrinth."   The Lion of Gaul
>>
>>
>>
>
>
> --
> Chris Chiasson
> http://chrischiasson.com/contact/chris_chiasson
>
>

Andrzej Kozlowski
Tokyo, Japan

```

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