dollar-log formatting example

dollar_log_formatting.r

## Homer Strong, September 2010
##
## This is an example of using dollar formatting with log10 scaling.
## See the commit
## http://github.com/strongh/ggplot2/commit/7402a13a8ad625a8acd3024c5726545a20ac838e

library(ggplot2) 
data(diamonds)

## On the current ggplot, the formatter argument is ignored when using 
## either scale_*_<trans>() or scale_*_continous(trans='<trans>').
## I wanted to use the log10 trans but keep the 'dollar' formatting, as with

ggplot(diamonds, aes(price)) + geom_histogram() + scale_x_continuous(trans='log10', formatter='dollar') 

## The x-axis labels are formatted now as '$10^4' (with the superscript properly raised), as 
## opposed to '10^4'. Even if there is another way to accomplish this, I feel like it's a 
## consistent use of the formatting options.
##
## By the way, the plot above can be found in the downloads section of my ggplot2 fork,
## http://github.com/strongh/ggplot2/downloads