Follow-Up Question to

*To*: mathgroup at smc.vnet.net*Subject*: [mg20187] Follow-Up Question to [mg20090]*From*: hanssen at zeiss.de*Date*: Tue, 5 Oct 1999 04:04:17 -0400*Sender*: owner-wri-mathgroup at wolfram.com

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