Puppet Function: prefix

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

Summary

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

Overview

prefix() ⇒ Hash

> Note: since Puppet 4.0.0 the general way to modify values is in array is by using the map function in Puppet. This example does the same as the example above: ['a', 'b', 'c'].map |$x| { “p$x” }

Examples:

*Usage*


prefix(['a','b','c'], 'p')
Will return: ['pa','pb','pc']

Returns:

  • (Hash) —

    or [Array] The passed values now contains the passed prefix



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# File 'vendor_modules/stdlib/lib/puppet/parser/functions/prefix.rb', line 7

newfunction(:prefix, type: :rvalue, doc: <<-DOC
  @summary
    This function applies a prefix to all elements in an array or a hash.

  @example **Usage**

    prefix(['a','b','c'], 'p')
    Will return: ['pa','pb','pc']

  > *Note:* since Puppet 4.0.0 the general way to modify values is in array is by using the map
  function in Puppet. This example does the same as the example above:
  ['a', 'b', 'c'].map |$x| { "p${x}" }

  @return [Hash] or [Array] The passed values now contains the passed prefix
  DOC
) 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.empty?

  enumerable = arguments[0]

  unless enumerable.is_a?(Array) || 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

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

  return result
end