Re: Follow-Up Question to
- To: mathgroup at smc.vnet.net
- Subject: [mg20204] Re: [mg20187] Follow-Up Question to [mg20090]
- From: "Andrzej Kozlowski" <andrzej at tuins.ac.jp>
- Date: Wed, 6 Oct 1999 21:06:25 -0400
- Sender: owner-wri-mathgroup at wolfram.com
But this is simply not true:
In[1]:=
disp = DisplayFunction -> Identity;
In[2]:=
ClearAttributes[Plot, HoldAll]
In[3]:=
SetAttributes[Plot, HoldFirst]
In[4]:=
Plot[x^3, {x, -1, 1}, disp]
Out[4]=
-Graphics-
No picture. You must have done something different.
--
Andrzej Kozlowski
Toyama International University
JAPAN
http://sigma.tuins.ac.jp
http://eri2.tuins.ac.jp
----------
>From: hanssen at zeiss.de
To: mathgroup at smc.vnet.net
>To: mathgroup at smc.vnet.net
>Subject: [mg20204] [mg20187] Follow-Up Question to [mg20090]
>Date: Tue, Oct 5, 1999, 17:04
>
> Hi, all
>
> Adam Smith rose the question, why nodisp in
>
> nodisp = DisplayFunction -> Identity
> graph1 = Plot[Sin[2 Pi x],{x,0,2},nodisp]
>
> does not work. From the answers in this group, we learned,
> that one either has to wrap nodisp into Evaluate
>
> graph1 = Plot[Sin[2 Pi x],{x,0,2},Evaluate[nodisp]]
>
> or use Block to temporarily deviate DisplayFunction to Identity
> and use Show outside the Block-construct to display the combined
> graphs or use one or the other package to combine different graphs.
>
> Plot has the Attribute HoldAll. However, if one changes this
> to HoldFirst (which might have other unwanted side effects),
> Evaluate around nodisp is still necessary. Can anybody in this
> group explain, why? It is just a matter of better understanding
> Hold and so on, rather than a question of combining graphics
> objects.
>
>
> sincerely
>
> A. Hanszen
>
>
>