Get docs for the functions you've got in puppet _AND_ your current module set

gistfile1.rb

require 'puppet'
Puppet[:parser] = 'future'
Puppet[:environment] = 'master'
Puppet[:manifest] = 'manifests/site.pp'
Puppet[:modulepath] = 'modules/:vendor/modules/'
Puppet.settings.initialize_app_defaults({
  :logdir => "/dev/null",
  :confdir => "/dev/null",
  :vardir => "/dev/null",
  :rundir => "/dev/null",
  :hiera_config => "/dev/null",
})
def functiondocs
  Puppet::Parser::Functions.autoloader.loadall
  data = {}
  Puppet::Parser::Functions.send(:merged_functions).each do |name, hash|
    ret = "#{name}\n#{"-" * name.to_s.length}\n"
    if hash[:doc]
      ret << Puppet::Util::Docs.scrub(hash[:doc])
    else
      ret << "Undocumented.\n"
    end
    ret << "\n\n- *Type*: #{hash[:type]}\n\n"
    data[name.to_s] = ret
  end
  data
end

func_name = ARGV.first
docs = functiondocs
if func_name
  if func_name == 'list'
    puts docs.keys.join("\n")
  else
    if doc = docs[func_name]
      puts doc
    else
      puts "Function #{func_name} not found!"
    end
  end
else
  docs.keys.sort.each do |name|
     puts docs[name]
  end
end