Puppet Function: prefix

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

Overview

prefix() ⇒ Any

This function applies a prefix to all elements in an array or a hash.

Examples:

prefix(['a','b','c'], 'p')

Will return: ['pa','pb','pc']

Returns:

  • (Any) 


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# File 'puppet/modules/stdlib/lib/puppet/parser/functions/prefix.rb', line 6

newfunction(:prefix, :type => :rvalue, :doc => <<-EOS
This function applies a prefix to all elements in an array or a hash.

*Examples:*

  prefix(['a','b','c'], 'p')

Will return: ['pa','pb','pc']
  EOS
) do |arguments|

  # Technically we support two arguments but only first is mandatory ...
  raise(Puppet::ParseError, "prefix(): Wrong number of arguments " +
    "given (#{arguments.size} for 1)") if arguments.size < 1

  enumerable = arguments[0]

  unless enumerable.is_a?(Array) or enumerable.is_a?(Hash)
    raise Puppet::ParseError, "prefix(): expected first argument to be an Array or a Hash, got #{enumerable.inspect}"
  end

  prefix = arguments[1] if arguments[1]

  if prefix
    unless prefix.is_a?(String)
      raise Puppet::ParseError, "prefix(): expected second argument to be a String, got #{prefix.inspect}"
    end
  end

  if enumerable.is_a?(Array)
    # Turn everything into string same as join would do ...
    result = enumerable.collect do |i|
      i = i.to_s
      prefix ? prefix + i : i
    end
  else
    result = Hash[enumerable.map do |k,v|
      k = k.to_s
      [ prefix ? prefix + k : k, v ]
    end]
  end

  return result
end