Automated ggplot2 example gallery in knitr
===

I'm trying to produce a gallery of `ggplot2` geoms using `knitr`. In order to do this quickly I thought to use the built-in `example`s to populate the content.

After some trial and error I've got to this point:

    \documentclass[a4paper,titlepage]{tufte-handout}
    \usepackage{pdflscape}
    \usepackage{graphicx}
    \usepackage{alltt}
    
    <<setup, include=FALSE, cache=FALSE>>=
    options(replace.assign=TRUE,tidy=TRUE)
    library(ggplot2)
    library(plyr)
    library(scales)
    geoms <- setdiff(apropos("^geom_"),"geom_blank")
    @
    
    \title{ggplot2 Gallery}
    
    \begin{document}
    \maketitle
    
    <<examples, echo=FALSE, comment=NA>>=
    for(i in geoms){
    	writeLines(paste0("\\section{",gsub("_","\\\\_",i),"}"))
    	do.call("example",list(i))
    }
    @
    
    \end{document}

But there are still a number of issues I can't resolve:

 - I can't seem to be able to mix `markup` and `asis` results options within the chunk so that section headings get produced. (This will be crucial for navigation of the document later). Is there any other way of producing writing LaTex within the chunk?

 - There are some examples which throw errors (which is why `geom_blank` is excluded). The [knitr documentation][1] states that computation continues in the case of errors, but it only seems to be the knit process which continues; the example loop ceases at that point. Is there a way to avoid the parts of the examples that are errors?

 - The `example` code output isn't syntaxed highlighted. (Useful but not essential).


  [1]: http://yihui.name/knitr/options