Puppet Function: range

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

Summary

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

Overview

range() ⇒ Any

NB Be explicit in including trailing zeros. Otherwise the underlying ruby function will fail.

> Note:

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

The Puppet Language support Integer and Float ranges by using the type system. Those are suitable for iterating a given number of times.

Integer[0, 9].each |$x| { notice($x) } # notices 0, 1, 2, ... 9

Examples:

*Usage*

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"]

range("0", "9", "2")
Will return: [0,2,4,6,8]

Returns:

  • (Any) —

    the range is extrapolated as an array

See Also:

  • step() function in Puppet for skipping values.


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# File 'vendor_modules/stdlib/lib/puppet/parser/functions/range.rb', line 8

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

  @return
    the range is extrapolated as an array

  @example **Usage**
    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"]

    range("0", "9", "2")
    Will return: [0,2,4,6,8]

  NB Be explicit in including trailing zeros. Otherwise the underlying ruby function will fail.

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

  The Puppet Language support Integer and Float ranges by using the type system. Those are suitable for
  iterating a given number of times.

  @see
    the step() function in Puppet for skipping values.

   Integer[0, 9].each |$x| { notice($x) } # notices 0, 1, 2, ... 9
  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

    raise(ArgumentError, 'range(): 3rd arg (step size) must be a non zero integer (e.g. 1 or -1)') if step.zero?

    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 %r{^.+$}.match?(value)
      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 %r{^\d+$}.match?(start.to_s)
    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).first(1_000_000).to_a

  return result
end