Handling multiline with HEREDOC

Writing multiline file fragments in Puppet mostly resulted in code that was hard to read, mostly due to indentation. With Puppet 4, the heredoc style was added. It is now possible to specify a heredoc tag and marker:

$motd_content = @(EOF)
  This system is managed by Puppet
  local changes will be overwritten by next Puppet run.
EOF

The heredoc tag starts with an @ sign followed by arbitrary string enclosed in parenthesis. The heredoc marker is the string given in the tag.

If variables are required inside the heredoc document, the variable interpolation can be enabled by putting the tag string in double quotes. Variables inside the heredoc are written like Puppet DSL variables: a dollar sign followed by the scope and the variable name:

$motd_content = @("EOF")
  Welcome to ${::fqdn}.
  This system is managed by Puppet version ${::puppetversion}.
  Local changes will be overwritten by the next Puppet run
EOF

Normally, heredoc does not handle escape sequences. Escape...