Puppet Function: range

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

Overview

range() ⇒ Any

When given range in the form of (start, stop) it will extrapolate a range as an array.

Examples:

range("0", "9")

Will return: [0,1,2,3,4,5,6,7,8,9]

range("00", "09")

Will return: [0,1,2,3,4,5,6,7,8,9] (Zero padded strings are converted to integers automatically)

range("a", "c")

Will return: [“a”,“b”,“c”]

range("host01", "host10")

Will return: [“host01”, “host02”, …, “host09”, “host10”] NB Be explicit in including trailing zeros. Otherwise the underlying ruby function will fail.

Passing a third argument will cause the generated range to step by that interval, e.g.

range("0", "9", "2")

Will return: [0,2,4,6,8]

Returns:

  • (Any) 


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# File 'lib/puppet/parser/functions/range.rb', line 6

newfunction(:range, :type => :rvalue, :doc => <<-DOC
  When given range in the form of (start, stop) it will extrapolate a range as
  an array.

  *Examples:*

      range("0", "9")

  Will return: [0,1,2,3,4,5,6,7,8,9]

      range("00", "09")

  Will return: [0,1,2,3,4,5,6,7,8,9] (Zero padded strings are converted to
  integers automatically)

      range("a", "c")

  Will return: ["a","b","c"]

      range("host01", "host10")
  Will return: ["host01", "host02", ..., "host09", "host10"]
  NB Be explicit in including trailing zeros. Otherwise the underlying ruby function will fail.

  Passing a third argument will cause the generated range to step by that
  interval, e.g.

      range("0", "9", "2")

  Will return: [0,2,4,6,8]
  DOC
           ) do |arguments|

  raise(Puppet::ParseError, 'range(): Wrong number of arguments given (0 for 1)') if arguments.empty?

  if arguments.size > 1
    start = arguments[0]
    stop  = arguments[1]
    step  = arguments[2].nil? ? 1 : arguments[2].to_i.abs

    type = '..' # Use the simplest type of Range available in Ruby

  else # arguments.size == 1
    value = arguments[0]

    m = value.match(%r{^(\w+)(\.\.\.?|\-)(\w+)$})
    if m
      start = m[1]
      stop  = m[3]

      type = m[2]
      step = 1
    elsif value =~ %r{^.+$}
      raise(Puppet::ParseError, "range(): Unable to compute range from the value: #{value}")
    else
      raise(Puppet::ParseError, "range(): Unknown range format: #{value}")
    end
  end

  # If we were given an integer, ensure we work with one
  if start.to_s =~ %r{^\d+$}
    start = start.to_i
    stop  = stop.to_i
  else
    start = start.to_s
    stop  = stop.to_s
  end

  range = case type
          when %r{^(..|-)$} then (start..stop)
          when '...' then (start...stop) # Exclusive of last element
          end

  result = range.step(step).to_a

  return result
end