rake-prereqs-dot

#!/usr/bin/env ruby

# Usage: rake -P | rake-prereqs-dot | dotty -

# Convert the output of `rake -P/--prereqs`
# ("Display the tasks and dependencies, then exit.")
# to a graphviz graph

# Sample input
# -8<-
# rake check:osc
# rake check:syntax
# rake console
# rake osc:build
#     check:osc
#     package
# rake osc:commit
#     osc:build
# rake osc:sr
#     osc:commit
# rake package
#     check:syntax
#     tarball
# rake tarball
# -8<-

puts "digraph g {"

task = "?"
ARGF.each_line do |line|
  line.chomp!
  if line =~ /^rake (.*)/
    task = $1
    puts "\"#{task}\";"
  else
    puts "\"#{task}\" -> \"#{line.strip}\";"
  end
end

puts "}"