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 > > >