Build a GraphViz compatible file showing which functions call each other in an R package.

fw2dot.R

# use MVB's foodweb to build a graphviz-compatible "dot" file
# this can then be used to generate a svg of the graph using:
# $ dot -Tsvg file.dot -o file.svg

# example usage:
# fw2dot("mrds","mrds.dot")

library(mvbutils)

fw2dot <- function(package.name,filename){

  # use foodweb from mvbutils to build an adjacency matrix
  funmat <- foodweb(where=asNamespace(package.name),plotting=FALSE,
                    generics=c( "c", "["))$funmat

  # pre-initialise the number of rows we'll need (# of connections
  store <- character(sum(funmat[upper.tri(funmat)]))

  # grab the names of the nodes in the graph
  mat.names <- colnames(funmat)

  # iterate over the adjacency matrix building the lines for the
  # dot file.
  k <- 1
  for(i in 1:nrow(funmat)){
    for(j in (i+1):nrow(funmat)){
      if( j > nrow(funmat) | i > nrow(funmat)) next
      if(funmat[i,j]){
        store[k] <- paste0("\"",mat.names[j],"\" -> \"",mat.names[i],"\"")
        k <- k + 1
      }
    }
  }

  # add the preamble
  store <- c(paste0("digraph ", package.name," {"),store,"}")

  # write the dot file
  wfile <- file(filename,"wb")
  writeLines(store,wfile)
  close(wfile)

  invisible()
}