Re: The side-effects of mixing TraditionalForm inside expressions.

• To: mathgroup at smc.vnet.net
• Subject: [mg110802] Re: The side-effects of mixing TraditionalForm inside expressions.
• From: AES <siegman at stanford.edu>
• Date: Wed, 7 Jul 2010 07:42:29 -0400 (EDT)
• References: <201007051002.GAA15102@smc.vnet.net> <i0urh5\$6l9\$1@smc.vnet.net>

```In article <i0urh5\$6l9\$1 at smc.vnet.net>,
Andrzej Kozlowski <akozlowski at gmail.com> wrote:

> 1 + Unevaluated[1]
>
>  2

Fascinating.  I'd call this one more classic Mathematica gotcha, and one
more example of fairly poor quality of Mathematica documentation -- or
at least of the very arcane character of Mathematica for "ordinary
users", once you get to any depth within it.

Help Browser says:

Unevaluated[expr]
represents the unevaluated form of expr when it appears as
the argument to a function.

So, what does Unevaluated[expr] do when it is NOT the argument to a
function?

(The previous statement I'd say clearly implies that there are times
when Unevaluated[expr] does appear as an arg to function, and therefore
times when it does not -- and both need to be defined.)

So, if Unevaluated[expr] is entered all by itself in a cell, is it then
"the argument to a function"?

If the cell contains 1 + Unevaluated[expr] as above, does that make the
Unevaluated[expr] an argument to a function -- or not?  (I can see
arguing that above queries either way -- and digging further down into
the Help Browser examples is not very helpful.)

How would one find out from Mathematica documentation what "argument to
a function" means, precisely?   Is there any significance to "argument
to" rather than the (I think) more common usage "argument of"?

Is Unevaluated[expr] used in a syntactically acceptable way _always_ the
argument to a function?

```

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