watch a directory for changes to .Rmd (knitr+markdown files) and if any change, knit them. Best used with Marked by Brett Terpstra (set it to watch the .md files that knitr will generate).

watchr.R

# watch all .Rmd files in a directory, if any change, knit them

library(knitr)

# use watch from Hadley's testthat package
library(testthat)


watchr<-function(path){
  # the path supplied here can just be something like "./"

  # taken from auto-test.r
  knit_it<-function(added, deleted, modified) {
    changed <- normalizePath(c(added, modified))

    for(a_file in changed){
      knit(a_file)
    }

    TRUE
  }

  watch(path,knit_it,".Rmd")

}