Module: Puppet::Pops::Types::Iterable Private

Included in:
TreeIterator, Iterator
Defined in:
lib/puppet/pops/types/iterable.rb,
lib/puppet/pops/types/tree_iterators.rb

Overview

This module is part of a private API. You should avoid using this module if possible, as it may be removed or be changed in the future.

The runtime Iterable type for an Iterable

Defined Under Namespace

Classes: BreadthFirstTreeIterator, DepthFirstTreeIterator, TreeIterator

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.asserted_iterable(my_caller, obj, infer_elements = false) ⇒ Iterable?

Produces an ‘Iterable` for one of the following types with the following characterstics:

‘String` - yields each character in the string `Array` - yields each element in the array `Hash` - yields each key/value pair as a two element array `Integer` - when positive, yields each value from zero to the given number `PIntegerType` - yields each element from min to max (inclusive) provided min < max and neither is unbounded. `PEnumtype` - yields each possible value of the enum. `Range` - yields an iterator for all elements in the range provided that the range start and end

are both integers or both strings and start is less than end using natural ordering.

‘Dir` - yields each name in the directory

An ‘ArgumentError` is raised for all other objects.

Parameters:

  • my_caller (Object) —

    The calling object to reference in errors

  • obj (Object) —

    The object to produce an ‘Iterable` for

  • infer_elements (Boolean) (defaults to: false) —

    Whether or not to recursively infer all elements of obj. Optional

Returns:

  • (Iterable, nil) —

    The produced ‘Iterable`

Raises:

  • (ArgumentError) —

    In case an ‘Iterable` cannot be produced



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# File 'lib/puppet/pops/types/iterable.rb', line 34

def self.asserted_iterable(my_caller, obj, infer_elements = false)
  iter = on(obj, nil, infer_elements)
  raise ArgumentError, "#{my_caller.class}(): wrong argument type (#{obj.class}; is not Iterable." if iter.nil?

  iter
end

.on(o, element_type = nil, infer_elements = true) ⇒ Iterable?

Produces an ‘Iterable` for one of the following types with the following characteristics:

‘String` - yields each character in the string `Array` - yields each element in the array `Hash` - yields each key/value pair as a two element array `Integer` - when positive, yields each value from zero to the given number `PIntegerType` - yields each element from min to max (inclusive) provided min < max and neither is unbounded. `PEnumtype` - yields each possible value of the enum. `Range` - yields an iterator for all elements in the range provided that the range start and end

are both integers or both strings and start is less than end using natural ordering.

‘Dir` - yields each name in the directory

The value ‘nil` is returned for all other objects.

Parameters:

  • o (Object) —

    The object to produce an ‘Iterable` for

  • element_type (PAnyType) (defaults to: nil) —

    the element type for the iterator. Optional

  • infer_elements (Boolean) (defaults to: true) —

    if element_type is nil, whether or not to recursively infer types for the entire collection. Optional

Returns:

  • (Iterable, nil) —

    The produced ‘Iterable` or `nil` if it couldn’t be produced



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# File 'lib/puppet/pops/types/iterable.rb', line 63

def self.on(o, element_type = nil, infer_elements = true)
  case o
  when IteratorProducer
    o.iterator
  when Iterable
    o
  when String
    Iterator.new(PStringType.new(PIntegerType.new(1, 1)), o.each_char)
  when Array
    if o.empty?
      Iterator.new(PUnitType::DEFAULT, o.each)
    else
      if element_type.nil? && infer_elements
        tc = TypeCalculator.singleton
        element_type = PVariantType.maybe_create(o.map { |e| tc.infer_set(e) })
      end
      Iterator.new(element_type, o.each)
    end
  when Hash
    # Each element is a two element [key, value] tuple.
    if o.empty?
      HashIterator.new(PHashType::DEFAULT_KEY_PAIR_TUPLE, o.each)
    else
      if element_type.nil? && infer_elements
        tc = TypeCalculator.singleton
        element_type =
          PTupleType
          .new([
                 PVariantType.maybe_create(o.keys.map { |e| tc.infer_set(e) }),
                 PVariantType.maybe_create(o.values.map { |e| tc.infer_set(e) })
               ],
               PHashType::KEY_PAIR_TUPLE_SIZE)
      end
      HashIterator.new(element_type, o.each_pair)
    end
  when Integer
    if o == 0
      Iterator.new(PUnitType::DEFAULT, o.times)
    elsif o > 0
      IntegerRangeIterator.new(PIntegerType.new(0, o - 1))
    else
      nil
    end
  when PIntegerType
    # a finite range will always produce at least one element since it's inclusive
    o.finite_range? ? IntegerRangeIterator.new(o) : nil
  when PEnumType
    Iterator.new(o, o.values.each)
  when PTypeAliasType
    on(o.resolved_type)
  when Range
    min = o.min
    max = o.max
    if min.is_a?(Integer) && max.is_a?(Integer) && max >= min
      IntegerRangeIterator.new(PIntegerType.new(min, max))
    elsif min.is_a?(String) && max.is_a?(String) && max >= min
      # A generalized element type where only the size is inferred is used here since inferring the full
      # range might waste a lot of memory.
      if min.length < max.length
        shortest = min
        longest = max
      else
        shortest = max
        longest = min
      end
      Iterator.new(PStringType.new(PIntegerType.new(shortest.length, longest.length)), o.each)
    else
      # Unsupported range. It's either descending or nonsensical for other reasons (float, mixed types, etc.)
      nil
    end
  else
    # Not supported. We cannot determine the element type
    nil
  end
end

.unbounded?(object) ⇒ Boolean

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Answers the question if there is an end to the iteration. Puppet does not currently provide any unbounded iterables.

Returns:

  • (Boolean) —

    ‘true` if the iteration is unbounded



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# File 'lib/puppet/pops/types/iterable.rb', line 143

def self.unbounded?(object)
  case object
  when Iterable
    object.unbounded?
  when String, Integer, Array, Hash, Enumerator, PIntegerType, PEnumType, Dir
    false
  else
    TypeAsserter.assert_instance_of('', PIterableType::DEFAULT, object, false)
    !object.respond_to?(:size)
  end
end

Instance Method Details

#each(&block) ⇒ Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future. 



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# File 'lib/puppet/pops/types/iterable.rb', line 155

def each(&block)
  step(1, &block)
end

#element_type ⇒ Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future. 



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# File 'lib/puppet/pops/types/iterable.rb', line 159

def element_type
  PAnyType::DEFAULT
end

#hash_style? ⇒ Boolean

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Returns:

  • (Boolean) 


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# File 'lib/puppet/pops/types/iterable.rb', line 181

def hash_style?
  false
end

#reverse_each(&block) ⇒ Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Raises:

  • (ArgumentError) 


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# File 'lib/puppet/pops/types/iterable.rb', line 163

def reverse_each(&block)
  # Default implementation cannot propagate reverse_each to a new enumerator so chained
  # calls must put reverse_each last.
  raise ArgumentError, 'reverse_each() is not implemented'
end

#step(step, &block) ⇒ Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Raises:

  • (ArgumentError) 


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# File 'lib/puppet/pops/types/iterable.rb', line 169

def step(step, &block)
  # Default implementation cannot propagate step to a new enumerator so chained
  # calls must put stepping last.
  raise ArgumentError, 'step() is not implemented'
end

#to_a ⇒ Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Raises:



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# File 'lib/puppet/pops/types/iterable.rb', line 175

def to_a
  raise Puppet::Error, 'Attempt to create an Array from an unbounded Iterable' if unbounded?

  super
end

#unbounded? ⇒ Boolean

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Returns:

  • (Boolean) 


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# File 'lib/puppet/pops/types/iterable.rb', line 185

def unbounded?
  true
end