Puppet Extension Point

basename-ast.txt

AST::VarDef
  AST::Variable(file)
  AST::Function(basename)
    AST::String(...)

basename-call.rb

scope.setvar('file', scope.function_basename('...'))

basename-token-stream.txt

VARIABLE(file) EQUALS NAME(basename) LPAREN STRING(...) RPAREN

basename.pp

$file = basename('/var/lib/puppet/ssl/certs/mycert.pem')

basename.rb

module Puppet::Parser::Functions
  newfunction(:basename, :type => :rvalue, :doc => <<-EOS
Returns the basename of a full pathname. For instance if called 
with '/path/to/myfile.txt' will return 'myfile.txt'.
    EOS
  ) do |args|
    
    raise(Puppet::ParseError, "basename(): Wrong number of arguments given (#{args.size} instead of 1)") if arguments.size != 1
    
    File.basename(args[0])
  end
end

hardware_platform.rb

# drop this in a module lib/facter/
Facter.add("hardware_platform") do
  setcode do
    %x{/bin/uname -i}.chomp
  end
end