Re: Re: holding boxes verbatim

• To: mathgroup at smc.vnet.net
• Subject: [mg56486] Re: [mg56258] Re: holding boxes verbatim
• From: Chris Chiasson <chris.chiasson at gmail.com>
• Date: Tue, 26 Apr 2005 21:52:41 -0400 (EDT)
• References: <00aa01c544e3\$6db4af30\$6400a8c0@Main> <200504200931.FAA17986@smc.vnet.net>
• Reply-to: Chris Chiasson <chris.chiasson at gmail.com>
• Sender: owner-wri-mathgroup at wolfram.com

```Dear Mathgroup gurus,

Thank you for your replies to my questions in this thread so far.

The notation package is really independent of the question I was
asking. I found the solution to the simple examples I gave above and
to the problem I was trying to solve earlier. However, I have a new
problem now...

But first, the solutions I found are as follows (evaluate them for the
two dimensional version):

(*b*(a + s*m) -> b (a + m s) is fixed by using :*)
RowBox[{"b", "*", RowBox[{"(", RowBox[{"a", "+", RowBox[{"s", "*",
"m"}]}], ")"}]}] // DisplayForm
(*(x)^(1/2) -> sqrt(x) is fiex by using :*)
RowBox[{RowBox[{"(", "x", ")"}], "^", RowBox[{"(", RowBox[{
"1", "/", "2"}], ")"}]}] // DisplayForm
(*(x/y)(h/g) is fixed by using :*)
RowBox[{RowBox[{"(", RowBox[{"x", "/", "y"}], ")"}], RowBox[{
"(", RowBox[{"h", "/", "g"}], ")"}]}] // DisplayForm

Now for the new problem:
The expression I wanted to output was this (evaluate it for 2d):

RowBox[{"CA",
"==", RowBox[{RowBox[{"(",
FractionBox[
RowBox[{"99", "
", "Kilo", "
", "Pascal"}], RowBox[{"
P", "[", RowBox[{"a", ",", "db"}], "]
"}]], ")"}], SuperscriptBox[RowBox[{"(", \
FractionBox[RowBox[{"T",
"[", "db", "]"}],
RowBox[{"298", " ", "Kelvin"}]], ")"}], RowBox[{"1", "/
", "2"}]]}]}] // DisplayForm

However, I noticed that the one way Notations I defined (using <==)
are not applied. For instance T[db] (which is RowBox[{"T","[", "db",
"]"}] in boxes) in the output of the last command would be T
subscripted by db.

Does anyone know how to cause the Notation package to "process"
something that is already in box form?

I imagine one solution would be to selectively evaluate the above
expression with MakeExpression so that RowBox[{"T","[", "db", "]"}]
turned into T[db], which could then be processed by the notation
package.

Another solution might be to define a procedure to call on output
(isn't there a variable where one can set this?) which would replace
RowBox[{"T","[", "db", "]"}] with RobBox[SubscriptBox["T","db"]].

I already have a bunch of notations set up that I would like to reuse,
but I can redo it all if need be. What is the right way to go about
"using Notation rules on boxes"?

Thank you for your very valuable time,

On 4/20/05, Chris Chiasson <chris.chiasson at gmail.com> wrote:
> As a follow up to those who requested clairification:
>
> Consider the simple examples:
>
> HoldAllComplete[b*(a + s*m)] (*notice the order of the vairables
> inside the inner Times is rearranged on output*)
> HoldAllComplete[(x)^(1/2)] (*notice the reformatting of an expression
> to the power 1/2 is reformatted to the square root of the expression*)
> HoldAllComplete[(x/y)(h/g)] (*notice the elimination of the parenthesis*)
>
> The reason these things happen is that the boxes are parsed into
> Mathematica input such as Times[b,Plus[a,Times[s,m]]].
>
> I need a way to work directly with the boxes, but still at least do
> some variable substitution.
>
> Thank you again for your time.
>
> On 4/19/05, Carl K. Woll <carlw at u.washington.edu> wrote:
> > "Chris Chiasson" <chris.chiasson at gmail.com> wrote in message
> > news:d42l18\$3gf\$1 at smc.vnet.net...
> > > Dear Math Group gurus,
> > >
> > > Mathematica is annoying me. I would like some way to type in a two
> > > dimensional box form (representing an arbitrary expression) and assign
> > > it to a symbol. I would then like to be able to operate on the
> > > expression by, for instance:
> > > 1 printing it
> > > 2 printing it with some variables' values substitued into it
> > > 3 and finally evaluating it
> > >
> > > Hold and its variants do not do the job because they prevent
> > > expression evaluation, but I need something that will keep its box
> > > form exactly as I have typed it.
> > >
> > > Please, how does one do this?
> > >
> > > A method for doing this is very useful to me because my professors
> > > like to see the variables substitued into the original (not
> > > Mathematica reparsed original, but verbatim original) equations.
> > >
> > > Thank you for your very valuable time,
> >
> > An example of the desired behavior would be helpful. At any rate, have you
> > tried using HoldForm? For example:
> >
> > expr = HoldForm[2^(x+1)];
> > expr
> > expr /. x->2
> > ReleaseHold[ expr /. x->2 ]
> >
> >  x + 1
> > 2
> >  2 + 1
> > 2
> > 8
> >
> > I used InputForm instead of a 2D box form for expr for legibility, but using
> > a 2D box form for expr won't cause any problems.
> >
> > If the above is not helpful, please give an example of the behavior you
> > desire.
> >
> > Carl Woll
> >
> >
>
> --
> Chris Chiasson
> Kettering University
> Mechanical Engineering
> 1 810 265 3161
>
>

--
Chris Chiasson
http://chrischiasson.com
Kettering University
Mechanical Engineering