Puppet Function: merge

Defined in:
puppet/modules/stdlib/lib/puppet/parser/functions/merge.rb
Function type:
Ruby 3.x API

Overview

merge() ⇒ Any

Merges two or more hashes together and returns the resulting hash.

For example:

$hash1 = {'one' => 1, 'two', => 2}
$hash2 = {'two' => 'dos', 'three', => 'tres'}
$merged_hash = merge($hash1, $hash2)
# The resulting hash is equivalent to:
# $merged_hash =  {'one' => 1, 'two' => 'dos', 'three' => 'tres'}

When there is a duplicate key, the key in the rightmost hash will “win.”

Returns:

  • (Any) 


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# File 'puppet/modules/stdlib/lib/puppet/parser/functions/merge.rb', line 2

newfunction(:merge, :type => :rvalue, :doc => <<-'ENDHEREDOC') do |args|
  Merges two or more hashes together and returns the resulting hash.

  For example:

      $hash1 = {'one' => 1, 'two', => 2}
      $hash2 = {'two' => 'dos', 'three', => 'tres'}
      $merged_hash = merge($hash1, $hash2)
      # The resulting hash is equivalent to:
      # $merged_hash =  {'one' => 1, 'two' => 'dos', 'three' => 'tres'}

  When there is a duplicate key, the key in the rightmost hash will "win."

  ENDHEREDOC

  if args.length < 2
    raise Puppet::ParseError, ("merge(): wrong number of arguments (#{args.length}; must be at least 2)")
  end

  # The hash we accumulate into
  accumulator = Hash.new
  # Merge into the accumulator hash
  args.each do |arg|
    next if arg.is_a? String and arg.empty? # empty string is synonym for puppet's undef
    unless arg.is_a?(Hash)
      raise Puppet::ParseError, "merge: unexpected argument type #{arg.class}, only expects hash arguments"
    end
    accumulator.merge!(arg)
  end
  # Return the fully merged hash
  accumulator
end