[R] slide show with R

[George_Heine@blm.gov]

Trying to use R to build an interactive "slide show", to be displayed on a
projector.  The purpose of the presentation is to show how one could
construct a simple graph using R.  It is meant as a general overview rather
than as detailed instruction.

For example, something like the following sequence of commands.    At
lecture time, I want the interpreter to read these commands one at a time
from a file, display and execute the command, (or two or three commands)
and then wait for another prompt.

pale.yellow="#ffff99"
par(bg=pale.yellow)
plot(c(0,2*pi),c(-1,1),type="n",ylab="",yaxt="n")
mirror<-function(t) { c(t,rev(2*max(t)-t)) }
z<-log(1:1000)/log(1000)
zz<-z*pi/2
zzz<-mirror(mirror(zz))
polygon(zzz,sin(25*zzz)*sin(zzz),border="blue")
polygon(zzz,sin(5*zzz)*sin(zzz),border="green")
polygon(zzz,sin(zzz),lwd=2)
points(zzz,rep(0,length(zzz)),col="red",pch="|")


Wrapping the following around each command works, sort of :

a<-expression(<command>)
x<-readline(a)
eval(a)

However, this doesn't work properly for the function definition, and it
gets very clumsy to display two or three lines as a block and then
evaluate.

Any help would be much appreciated.


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George Heine, PhD
Mathematical Analyst
National IRM Center
U.S. Bureau of Land Management
voice   (303) 236-0099
fax       (303) 236-1974
cell      (303) 905-5382
pager   gheine at my2way.com
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