delete_at.rb #1

#
# delete_at.rb
#

module Puppet::Parser::Functions
  newfunction(:delete_at, :type => :rvalue, :doc => <<-EOS
Deletes a determined indexed value from an array.

*Examples:*

    delete_at(['a','b','c'], 1)

Would return: ['a','c']
    EOS
  ) do |arguments|

    raise(Puppet::ParseError, "delete_at(): Wrong number of arguments " +
      "given (#{arguments.size} for 2)") if arguments.size < 2

    array = arguments[0]

    unless array.is_a?(Array)
      raise(Puppet::ParseError, 'delete_at(): Requires array to work with')
    end

    index = arguments[1]

    if index.is_a?(String) and not index.match(/^\d+$/)
      raise(Puppet::ParseError, 'delete_at(): You must provide ' +
        'non-negative numeric index')
    end

    result = array.clone

    # Numbers in Puppet are often string-encoded which is troublesome ...
    index = index.to_i

    if index > result.size - 1 # First element is at index 0 is it not?
      raise(Puppet::ParseError, 'delete_at(): Given index ' +
        'exceeds size of array given')
    end

    result.delete_at(index) # We ignore the element that got deleted ...

    return result
  end
end

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