diff --git a/lib/puppet/pops/evaluator/closure.rb b/lib/puppet/pops/evaluator/closure.rb
index 974d77cd4..47c0a54e0 100644
--- a/lib/puppet/pops/evaluator/closure.rb
+++ b/lib/puppet/pops/evaluator/closure.rb
@@ -1,112 +1,112 @@
 
 # A Closure represents logic bound to a particular scope.
 # As long as the runtime (basically the scope implementation) has the behaviour of Puppet 3x it is not
 # safe to use this closure when the scope given to it when initialized goes "out of scope".
 #
 # Note that the implementation is backwards compatible in that the call method accepts a scope, but this
 # scope is not used.
 #
 # Note that this class is a CallableSignature, and the methods defined there should be used
 # as the API for obtaining information in a callable implementation agnostic way.
 #
 class Puppet::Pops::Evaluator::Closure < Puppet::Pops::Evaluator::CallableSignature
   attr_reader :evaluator
   attr_reader :model
   attr_reader :enclosing_scope
 
   def initialize(evaluator, model, scope)
     @evaluator = evaluator
     @model = model
     @enclosing_scope = scope
   end
 
   # marker method checked with respond_to :puppet_lambda
   # @api private
   # @deprecated Use the type system to query if an object is of Callable type, then use its signatures method for info
   def puppet_lambda()
     true
   end
 
   # compatible with 3x AST::Lambda
   # @api public
   def call(scope, *args)
     @evaluator.call(self, args, @enclosing_scope)
   end
 
   # Call closure with argument assignment by name
   def call_by_name(scope, args_hash, spill_over = false)
     @evaluator.call_by_name(self, args_hash, @enclosing_scope, spill_over)
   end
 
   # incompatible with 3x except that it is an array of the same size
   def parameters()
     @model.parameters || []
   end
 
   # Returns the number of parameters (required and optional)
   # @return [Integer] the total number of accepted parameters
   def parameter_count
     # yes, this is duplication of code, but it saves a method call
     (@model.parameters || []).size
   end
 
   # Returns the number of optional parameters.
   # @return [Integer] the number of optional accepted parameters
   def optional_parameter_count
     @model.parameters.count { |p| !p.value.nil? }
   end
 
   # @api public
   def parameter_names
     @model.parameters.collect {|p| p.name }
   end
 
   # @api public
   def type
     @callable || create_callable_type
   end
 
   # @api public
   def last_captures_rest?
     # TODO: No support for this yet
     false
   end
 
   # @api public
   def block_name
     # TODO: Lambda's does not support blocks yet. This is a placeholder
     'unsupported_block'
   end
 
   private
 
   def create_callable_type()
     t = Puppet::Pops::Types::PCallableType.new()
     tuple_t = Puppet::Pops::Types::PTupleType.new()
     # since closure lambdas are currently untyped, each parameter becomes Optional[Object]
     parameter_names.each do |name|
       # TODO: Change when Closure supports typed parameters
       tuple_t.addTypes(Puppet::Pops::Types::TypeFactory.optional_object())
     end
 
     # TODO: A Lambda can not currently declare varargs
     to = parameter_count
     from = to - optional_parameter_count
     if from != to
       size_t = Puppet::Pops::Types::PIntegerType.new()
-      size_t.from = size
-      size_t.to = size
+      size_t.from = from
+      size_t.to = to
       tuple_t.size_type = size_t
     end
     t.param_types = tuple_t
     # TODO: A Lambda can not currently declare that it accepts a lambda, except as an explicit parameter
     # being a Callable
     t
   end
 
   # Produces information about parameters compatible with a 4x Function (which can have multiple signatures)
   def signatures
     [ self ]
   end
 
 end
diff --git a/lib/puppet/pops/evaluator/evaluator_impl.rb b/lib/puppet/pops/evaluator/evaluator_impl.rb
index 46a4b69be..aed299118 100644
--- a/lib/puppet/pops/evaluator/evaluator_impl.rb
+++ b/lib/puppet/pops/evaluator/evaluator_impl.rb
@@ -1,1061 +1,1069 @@
 require 'rgen/ecore/ecore'
 require 'puppet/pops/evaluator/compare_operator'
 require 'puppet/pops/evaluator/relationship_operator'
 require 'puppet/pops/evaluator/access_operator'
 require 'puppet/pops/evaluator/closure'
 require 'puppet/pops/evaluator/external_syntax_support'
 
 # This implementation of {Puppet::Pops::Evaluator} performs evaluation using the puppet 3.x runtime system
 # in a manner largely compatible with Puppet 3.x, but adds new features and introduces constraints.
 #
 # The evaluation uses _polymorphic dispatch_ which works by dispatching to the first found method named after
 # the class or one of its super-classes. The EvaluatorImpl itself mainly deals with evaluation (it currently
 # also handles assignment), and it uses a delegation pattern to more specialized handlers of some operators
 # that in turn use polymorphic dispatch; this to not clutter EvaluatorImpl with too much responsibility).
 #
 # Since a pattern is used, only the main entry points are fully documented. The parameters _o_ and _scope_ are
 # the same in all the polymorphic methods, (the type of the parameter _o_ is reflected in the method's name;
 # either the actual class, or one of its super classes). The _scope_ parameter is always the scope in which
 # the evaluation takes place. If nothing else is mentioned, the return is always the result of evaluation.
 #
 # See {Puppet::Pops::Visitable} and {Puppet::Pops::Visitor} for more information about
 # polymorphic calling.
 #
 class Puppet::Pops::Evaluator::EvaluatorImpl
   include Puppet::Pops::Utils
 
   # Provides access to the Puppet 3.x runtime (scope, etc.)
   # This separation has been made to make it easier to later migrate the evaluator to an improved runtime.
   #
   include Puppet::Pops::Evaluator::Runtime3Support
   include Puppet::Pops::Evaluator::ExternalSyntaxSupport
 
   # This constant is not defined as Float::INFINITY in Ruby 1.8.7 (but is available in later version
   # Refactor when support is dropped for Ruby 1.8.7.
   #
   INFINITY = 1.0 / 0.0
 
   # Reference to Issues name space makes it easier to refer to issues
   # (Issues are shared with the validator).
   #
   Issues = Puppet::Pops::Issues
 
   def initialize
     @@eval_visitor   ||= Puppet::Pops::Visitor.new(self, "eval", 1, 1)
     @@lvalue_visitor   ||= Puppet::Pops::Visitor.new(self, "lvalue", 1, 1)
     @@assign_visitor   ||= Puppet::Pops::Visitor.new(self, "assign", 3, 3)
     @@string_visitor   ||= Puppet::Pops::Visitor.new(self, "string", 1, 1)
 
     @@type_calculator  ||= Puppet::Pops::Types::TypeCalculator.new()
     @@type_parser      ||= Puppet::Pops::Types::TypeParser.new()
 
     @@compare_operator     ||= Puppet::Pops::Evaluator::CompareOperator.new()
     @@relationship_operator ||= Puppet::Pops::Evaluator::RelationshipOperator.new()
 
     # Initialize the runtime module
     Puppet::Pops::Evaluator::Runtime3Support.instance_method(:initialize).bind(self).call()
   end
 
   # @api private
   def type_calculator
     @@type_calculator
   end
 
   # Polymorphic evaluate - calls eval_TYPE
   #
   # ## Polymorphic evaluate
   # Polymorphic evaluate calls a method on the format eval_TYPE where classname is the last
   # part of the class of the given _target_. A search is performed starting with the actual class, continuing
   # with each of the _target_ class's super classes until a matching method is found.
   #
   # # Description
   # Evaluates the given _target_ object in the given scope, optionally passing a block which will be
   # called with the result of the evaluation.
   #
   # @overload evaluate(target, scope, {|result| block})
   # @param target [Object] evaluation target - see methods on the pattern assign_TYPE for actual supported types.
   # @param scope [Object] the runtime specific scope class where evaluation should take place
   # @return [Object] the result of the evaluation
   #
   # @api
   #
   def evaluate(target, scope)
     begin
       @@eval_visitor.visit_this_1(self, target, scope)
     rescue StandardError => e
       if e.is_a? Puppet::ParseError
         raise e
       end
       fail(Issues::RUNTIME_ERROR, target, {:detail => e.message}, e)
     end
   end
 
   # Polymorphic assign - calls assign_TYPE
   #
   # ## Polymorphic assign
   # Polymorphic assign calls a method on the format assign_TYPE where TYPE is the last
   # part of the class of the given _target_. A search is performed starting with the actual class, continuing
   # with each of the _target_ class's super classes until a matching method is found.
   #
   # # Description
   # Assigns the given _value_ to the given _target_. The additional argument _o_ is the instruction that
   # produced the target/value tuple and it is used to set the origin of the result.
   # @param target [Object] assignment target - see methods on the pattern assign_TYPE for actual supported types.
   # @param value [Object] the value to assign to `target`
   # @param o [Puppet::Pops::Model::PopsObject] originating instruction
   # @param scope [Object] the runtime specific scope where evaluation should take place
   #
   # @api
   #
   def assign(target, value, o, scope)
     @@assign_visitor.visit_this_3(self, target, value, o, scope)
   end
 
   def lvalue(o, scope)
     @@lvalue_visitor.visit_this_1(self, o, scope)
   end
 
   def string(o, scope)
     @@string_visitor.visit_this_1(self, o, scope)
   end
 
   # Call a closure matching arguments by name - Can only be called with a Closure (for now), may be refactored later
   # to also handle other types of calls (function calls are also handled by CallNamedFunction and CallMethod, they
   # could create similar objects to Closure, wait until other types of defines are instantiated - they may behave
   # as special cases of calls - i.e. 'new').
   #
   # Call by name supports a "spill_over" mode where extra arguments in the given args_hash are introduced
   # as variables in the resulting scope.
   #
   # @raise ArgumentError, if there are to many or too few arguments
   # @raise ArgumentError, if given closure is not a Puppet::Pops::Evaluator::Closure
   #
   def call_by_name(closure, args_hash, scope, spill_over = false)
     raise ArgumentError, "Can only call a Lambda" unless closure.is_a?(Puppet::Pops::Evaluator::Closure)
     pblock = closure.model
     parameters = pblock.parameters || []
 
     if !spill_over && args_hash.size > parameters.size
       raise ArgumentError, "Too many arguments: #{args_hash.size} for #{parameters.size}" 
     end
 
     # associate values with parameters
     scope_hash = {}
     parameters.each do |p|
       scope_hash[p.name] = args_hash[p.name] || evaluate(p.value, scope)
     end
     missing = scope_hash.reduce([]) {|memo, entry| memo << entry[0] if entry[1].nil?; memo }
     unless missing.empty?
       optional = parameters.count { |p| !p.value.nil? }
       raise ArgumentError, "Too few arguments; no value given for required parameters #{missing.join(" ,")}"
     end
     if spill_over
       # all args from given hash should be used, nil entries replaced by default values should win
       scope_hash = args_hash.merge(scope_hash)
     end
 
     # Store the evaluated name => value associations in a new inner/local/ephemeral scope
     # (This is made complicated due to the fact that the implementation of scope is overloaded with
     # functionality and an inner ephemeral scope must be used (as opposed to just pushing a local scope
     # on a scope "stack").
 
     # Ensure variable exists with nil value if error occurs.
     # Some ruby implementations does not like creating variable on return
     result = nil
     begin
       scope_memo = get_scope_nesting_level(scope)
       # change to create local scope_from - cannot give it file and line - that is the place of the call, not
       # "here"
       create_local_scope_from(scope_hash, scope)
       result = evaluate(pblock.body, scope)
     ensure
       set_scope_nesting_level(scope, scope_memo)
     end
     result
   end
 
   # Call a closure - Can only be called with a Closure (for now), may be refactored later
   # to also handle other types of calls (function calls are also handled by CallNamedFunction and CallMethod, they
   # could create similar objects to Closure, wait until other types of defines are instantiated - they may behave
   # as special cases of calls - i.e. 'new')
   #
   # @raise ArgumentError, if there are to many or too few arguments
   # @raise ArgumentError, if given closure is not a Puppet::Pops::Evaluator::Closure
   #
   def call(closure, args, scope)
     raise ArgumentError, "Can only call a Lambda" unless closure.is_a?(Puppet::Pops::Evaluator::Closure)
     pblock = closure.model
     parameters = pblock.parameters || []
 
     raise ArgumentError, "Too many arguments: #{args.size} for #{parameters.size}" unless args.size <= parameters.size
 
-    # associate values with parameters
-    merged = parameters.zip(args)
     # calculate missing arguments
-    missing = parameters.slice(args.size, parameters.size - args.size).select {|p| p.value.nil? }
+    args_diff = parameters.size - args.size
+    missing = parameters.slice(args.size, args_diff).select {|p| p.value.nil? }
     unless missing.empty?
       optional = parameters.count { |p| !p.value.nil? }
       raise ArgumentError, "Too few arguments; #{args.size} for #{optional > 0 ? ' min ' : ''}#{parameters.size - optional}"
     end
+    # associate values with parameters (pad missing with :missing)
+    merged = parameters.zip(args.fill(:missing, args.size, args_diff))
 
     evaluated = merged.collect do |m|
       # m can be one of
       # m = [Parameter{name => "name", value => nil], "given"]
       #   | [Parameter{name => "name", value => Expression}, "given"]
       #
       # "given" is always an optional entry. If a parameter was provided then
       # the entry will be in the array, otherwise the m array will be a
       # single element.
       given_argument = m[1]
       argument_name = m[0].name
       default_expression = m[0].value
 
-      value = if default_expression
+      # Use default value if a value was not given (NOTE: An :undef overrides - just a nil overrides default in ruby).
+      value =
+      if given_argument == :missing && default_expression
+        # undef was given, use default when it exists
+        evaluate(default_expression, scope)
+      elsif m.size == 1 && default_expression
+        # no given value, use the default
         evaluate(default_expression, scope)
       else
+        # use the given value
         given_argument
       end
       [argument_name, value]
     end
 
     # Store the evaluated name => value associations in a new inner/local/ephemeral scope
     # (This is made complicated due to the fact that the implementation of scope is overloaded with
     # functionality and an inner ephemeral scope must be used (as opposed to just pushing a local scope
     # on a scope "stack").
 
     # Ensure variable exists with nil value if error occurs. 
     # Some ruby implementations does not like creating variable on return
     result = nil
     begin
       scope_memo = get_scope_nesting_level(scope)
       # change to create local scope_from - cannot give it file and line - that is the place of the call, not
       # "here"
       create_local_scope_from(Hash[evaluated], scope)
       result = evaluate(pblock.body, scope)
     ensure
       set_scope_nesting_level(scope, scope_memo)
     end
     result
   end
 
   protected
 
   def lvalue_VariableExpression(o, scope)
     # evaluate the name
     evaluate(o.expr, scope)
   end
 
   # Catches all illegal lvalues
   #
   def lvalue_Object(o, scope)
     fail(Issues::ILLEGAL_ASSIGNMENT, o)
   end
 
   # Assign value to named variable.
   # The '$' sign is never part of the name.
   # @example In Puppet DSL
   #   $name = value
   # @param name [String] name of variable without $
   # @param value [Object] value to assign to the variable
   # @param o [Puppet::Pops::Model::PopsObject] originating instruction
   # @param scope [Object] the runtime specific scope where evaluation should take place
   # @return [value<Object>]
   #
   def assign_String(name, value, o, scope)
     if name =~ /::/
       fail(Issues::CROSS_SCOPE_ASSIGNMENT, o.left_expr, {:name => name})
     end
     set_variable(name, value, o, scope)
     value
   end
 
   def assign_Numeric(n, value, o, scope)
     fail(Issues::ILLEGAL_NUMERIC_ASSIGNMENT, o.left_expr, {:varname => n.to_s})
   end
 
   # Catches all illegal assignment (e.g. 1 = 2, {'a'=>1} = 2, etc)
   #
   def assign_Object(name, value, o, scope)
     fail(Issues::ILLEGAL_ASSIGNMENT, o)
   end
 
   def eval_Factory(o, scope)
     evaluate(o.current, scope)
   end
 
   # Evaluates any object not evaluated to something else to itself.
   def eval_Object o, scope
     o
   end
 
   # Allows nil to be used as a Nop.
   # Evaluates to nil
   # TODO: What is the difference between literal undef, nil, and nop?
   #
   def eval_NilClass(o, scope)
     nil
   end
 
   # Evaluates Nop to nil.
   # TODO: or is this the same as :undef
   # TODO: is this even needed as a separate instruction when there is a literal undef?
   def eval_Nop(o, scope)
     nil
   end
 
   # Captures all LiteralValues not handled elsewhere.
   #
   def eval_LiteralValue(o, scope)
     o.value
   end
 
   def eval_LiteralDefault(o, scope)
     :default
   end
 
   def eval_LiteralUndef(o, scope)
     :undef # TODO: or just use nil for this?
   end
 
   # A QualifiedReference (i.e. a  capitalized qualified name such as Foo, or Foo::Bar) evaluates to a PType
   #
   def eval_QualifiedReference(o, scope)
     @@type_parser.interpret(o)
   end
 
   def eval_NotExpression(o, scope)
     ! is_true?(evaluate(o.expr, scope))
   end
 
   def eval_UnaryMinusExpression(o, scope)
     - coerce_numeric(evaluate(o.expr, scope), o, scope)
   end
 
   # Abstract evaluation, returns array [left, right] with the evaluated result of left_expr and
   # right_expr
   # @return <Array<Object, Object>> array with result of evaluating left and right expressions
   #
   def eval_BinaryExpression o, scope
     [ evaluate(o.left_expr, scope), evaluate(o.right_expr, scope) ]
   end
 
   # Evaluates assignment with operators =, +=, -= and
   #
   # @example Puppet DSL
   #   $a = 1
   #   $a += 1
   #   $a -= 1
   #
   def eval_AssignmentExpression(o, scope)
     name = lvalue(o.left_expr, scope)
     value = evaluate(o.right_expr, scope)
 
     case o.operator
     when :'=' # regular assignment
       assign(name, value, o, scope)
 
     when :'+='
       # if value does not exist and strict is on, looking it up fails, else it is nil or :undef
       existing_value = get_variable_value(name, o, scope)
       begin
         if existing_value.nil? || existing_value == :undef
           assign(name, value, o, scope)
         else
           # Delegate to calculate function to deal with check of LHS, and perform ´+´ as arithmetic or concatenation the
           # same way as ArithmeticExpression performs `+`.
           assign(name, calculate(existing_value, value, :'+', o.left_expr, o.right_expr, scope), o, scope)
         end
       rescue ArgumentError => e
         fail(Issues::APPEND_FAILED, o, {:message => e.message})
       end
 
     when :'-='
       # If an attempt is made to delete values from something that does not exists, the value is :undef (it is guaranteed to not
       # include any values the user wants deleted anyway :-)
       #
       # if value does not exist and strict is on, looking it up fails, else it is nil or :undef
       existing_value = get_variable_value(name, o, scope)
       begin
       if existing_value.nil? || existing_value == :undef
         assign(name, :undef, o, scope)
       else
         # Delegate to delete function to deal with check of LHS, and perform deletion
         assign(name, delete(get_variable_value(name, o, scope), value), o, scope)
       end
       rescue ArgumentError => e
         fail(Issues::APPEND_FAILED, o, {:message => e.message}, e)
       end
     else
       fail(Issues::UNSUPPORTED_OPERATOR, o, {:operator => o.operator})
     end
     value
   end
 
   ARITHMETIC_OPERATORS = [:'+', :'-', :'*', :'/', :'%', :'<<', :'>>']
   COLLECTION_OPERATORS = [:'+', :'-', :'<<']
 
   # Handles binary expression where lhs and rhs are array/hash or numeric and operator is +, - , *, % / << >>
   #
   def eval_ArithmeticExpression(o, scope)
     left, right = eval_BinaryExpression(o, scope)
     begin
       result = calculate(left, right, o.operator, o.left_expr, o.right_expr, scope)
     rescue ArgumentError => e
       fail(Issues::RUNTIME_ERROR, o, {:detail => e.message}, e)
     end
     result
   end
 
 
   # Handles binary expression where lhs and rhs are array/hash or numeric and operator is +, - , *, % / << >>
   #
   def calculate(left, right, operator, left_o, right_o, scope)
     unless ARITHMETIC_OPERATORS.include?(operator)
       fail(Issues::UNSUPPORTED_OPERATOR, left_o.eContainer, {:operator => o.operator})
     end
 
     if (left.is_a?(Array) || left.is_a?(Hash)) && COLLECTION_OPERATORS.include?(operator)
       # Handle operation on collections
       case operator
       when :'+'
         concatenate(left, right)
       when :'-'
         delete(left, right)
       when :'<<'
         unless left.is_a?(Array)
           fail(Issues::OPERATOR_NOT_APPLICABLE, left_o, {:operator => operator, :left_value => left})
         end
         left + [right]
       end
     else
       # Handle operation on numeric
       left = coerce_numeric(left, left_o, scope)
       right = coerce_numeric(right, right_o, scope)
       begin
         if operator == :'%' && (left.is_a?(Float) || right.is_a?(Float))
           # Deny users the fun of seeing severe rounding errors and confusing results
           fail(Issues::OPERATOR_NOT_APPLICABLE, left_o, {:operator => operator, :left_value => left})
         end
         result = left.send(operator, right)
       rescue NoMethodError => e
         fail(Issues::OPERATOR_NOT_APPLICABLE, left_o, {:operator => operator, :left_value => left})
       rescue ZeroDivisionError => e
         fail(Issues::DIV_BY_ZERO, right_o)
       end
       if result == INFINITY || result == -INFINITY
         fail(Issues::RESULT_IS_INFINITY, left_o, {:operator => operator})
       end
       result
     end
   end
 
   def eval_EppExpression(o, scope)
     scope["@epp"] = []
     evaluate(o.body, scope)
     result = scope["@epp"].join('')
     result
   end
 
   def eval_RenderStringExpression(o, scope)
     scope["@epp"] << o.value.dup
     nil
   end
 
   def eval_RenderExpression(o, scope)
     scope["@epp"] << string(evaluate(o.expr, scope), scope)
     nil
   end
 
   # Evaluates Puppet DSL ->, ~>, <-, and <~
   def eval_RelationshipExpression(o, scope)
     # First level evaluation, reduction to basic data types or puppet types, the relationship operator then translates this
     # to the final set of references (turning strings into references, which can not naturally be done by the main evaluator since
     # all strings should not be turned into references.
     #
     real = eval_BinaryExpression(o, scope)
     @@relationship_operator.evaluate(real, o, scope)
   end
 
   # Evaluates x[key, key, ...]
   #
   def eval_AccessExpression(o, scope)
     left = evaluate(o.left_expr, scope)
     keys = o.keys.nil? ? [] : o.keys.collect {|key| evaluate(key, scope) }
     Puppet::Pops::Evaluator::AccessOperator.new(o).access(left, scope, *keys)
   end
 
   # Evaluates <, <=, >, >=, and ==
   #
   def eval_ComparisonExpression o, scope
     left, right = eval_BinaryExpression o, scope
 
     begin
     # Left is a type
     if left.is_a?(Puppet::Pops::Types::PAbstractType)
       case o.operator
       when :'=='
         @@type_calculator.equals(left,right)
 
       when :'!='
         !@@type_calculator.equals(left,right)
 
       when :'<'
         # left can be assigned to right, but they are not equal
         @@type_calculator.assignable?(right, left) && ! @@type_calculator.equals(left,right)
       when :'<='
         # left can be assigned to right
         @@type_calculator.assignable?(right, left)
       when :'>'
         # right can be assigned to left, but they are not equal
         @@type_calculator.assignable?(left,right) && ! @@type_calculator.equals(left,right)
       when :'>='
         # right can be assigned to left
         @@type_calculator.assignable?(left, right)
       else
         fail(Issues::UNSUPPORTED_OPERATOR, o, {:operator => o.operator})
       end
     else
       case o.operator
       when :'=='
         @@compare_operator.equals(left,right)
       when :'!='
         ! @@compare_operator.equals(left,right)
       when :'<'
         @@compare_operator.compare(left,right) < 0
       when :'<='
         @@compare_operator.compare(left,right) <= 0
       when :'>'
         @@compare_operator.compare(left,right) > 0
       when :'>='
         @@compare_operator.compare(left,right) >= 0
       else
         fail(Issues::UNSUPPORTED_OPERATOR, o, {:operator => o.operator})
       end
     end
     rescue ArgumentError => e
       fail(Issues::COMPARISON_NOT_POSSIBLE, o, {
         :operator => o.operator,
         :left_value => left,
         :right_value => right,
         :detail => e.message}, e)
     end
   end
 
   # Evaluates matching expressions with type, string or regexp rhs expression.
   # If RHS is a type, the =~ matches compatible (assignable?) type.
   #
   # @example
   #   x =~ /abc.*/
   # @example
   #   x =~ "abc.*/"
   # @example
   #   y = "abc"
   #   x =~ "${y}.*"
   # @example
   #   [1,2,3] =~ Array[Integer[1,10]]
   # @return [Boolean] if a match was made or not. Also sets $0..$n to matchdata in current scope.
   #
   def eval_MatchExpression o, scope
     left, pattern = eval_BinaryExpression o, scope
     # matches RHS types as instance of for all types except a parameterized Regexp[R]
     if pattern.is_a?(Puppet::Pops::Types::PAbstractType)
       if pattern.is_a?(Puppet::Pops::Types::PRegexpType) && pattern.pattern
         # A qualified PRegexpType, get its ruby regexp
         pattern = pattern.regexp
       else
         # evaluate as instance?
         matched = @@type_calculator.instance?(pattern, left)
         # convert match result to Boolean true, or false
         return o.operator == :'=~' ? !!matched : !matched
       end
     end
 
     begin
       pattern = Regexp.new(pattern) unless pattern.is_a?(Regexp)
     rescue StandardError => e
       fail(Issues::MATCH_NOT_REGEXP, o.right_expr, {:detail => e.message}, e)
     end
     unless left.is_a?(String)
       fail(Issues::MATCH_NOT_STRING, o.left_expr, {:left_value => left})
     end
 
     matched = pattern.match(left) # nil, or MatchData
     set_match_data(matched, o, scope) # creates ephemeral
 
     # convert match result to Boolean true, or false
     o.operator == :'=~' ? !!matched : !matched
   end
 
   # Evaluates Puppet DSL `in` expression
   #
   def eval_InExpression o, scope
     left, right = eval_BinaryExpression o, scope
     @@compare_operator.include?(right, left)
   end
 
   # @example
   #   $a and $b
   # b is only evaluated if a is true
   #
   def eval_AndExpression o, scope
     is_true?(evaluate(o.left_expr, scope)) ? is_true?(evaluate(o.right_expr, scope)) : false
   end
 
   # @example
   #   a or b
   # b is only evaluated if a is false
   #
   def eval_OrExpression o, scope
     is_true?(evaluate(o.left_expr, scope)) ? true : is_true?(evaluate(o.right_expr, scope))
   end
 
   # Evaluates each entry of the literal list and creates a new Array
   # @return [Array] with the evaluated content
   #
   def eval_LiteralList o, scope
     o.values.collect {|expr| evaluate(expr, scope)}
   end
 
   # Evaluates each entry of the literal hash and creates a new Hash.
   # @return [Hash] with the evaluated content
   #
   def eval_LiteralHash o, scope
     h = Hash.new
     o.entries.each {|entry| h[ evaluate(entry.key, scope)]= evaluate(entry.value, scope)}
     h
   end
 
   # Evaluates all statements and produces the last evaluated value
   #
   def eval_BlockExpression o, scope
     r = nil
     o.statements.each {|s| r = evaluate(s, scope)}
     r
   end
 
   # Performs optimized search over case option values, lazily evaluating each
   # until there is a match. If no match is found, the case expression's default expression
   # is evaluated (it may be nil or Nop if there is no default, thus producing nil).
   # If an option matches, the result of evaluating that option is returned.
   # @return [Object, nil] what a matched option returns, or nil if nothing matched.
   #
   def eval_CaseExpression(o, scope)
     # memo scope level before evaluating test - don't want a match in the case test to leak $n match vars
     # to expressions after the case expression.
     #
     with_guarded_scope(scope) do
       test = evaluate(o.test, scope)
       result = nil
       the_default = nil
       if o.options.find do |co|
         # the first case option that matches
         if co.values.find do |c|
           the_default = co.then_expr if c.is_a? Puppet::Pops::Model::LiteralDefault
           is_match?(test, evaluate(c, scope), c, scope)
         end
         result = evaluate(co.then_expr, scope)
         true # the option was picked
         end
       end
         result # an option was picked, and produced a result
       else
         evaluate(the_default, scope) # evaluate the default (should be a nop/nil) if there is no default).
       end
     end
   end
 
   # Evaluates a CollectExpression by transforming it into a 3x AST::Collection and then evaluating that.
   # This is done because of the complex API between compiler, indirector, backends, and difference between
   # collecting virtual resources and exported resources.
   #
   def eval_CollectExpression o, scope
     # The Collect Expression and its contained query expressions are implemented in such a way in
     # 3x that it is almost impossible to do anything about them (the AST objects are lazily evaluated,
     # and the built structure consists of both higher order functions and arrays with query expressions
     # that are either used as a predicate filter, or given to an indirection terminus (such as the Puppet DB
     # resource terminus). Unfortunately, the 3x implementation has many inconsistencies that the implementation
     # below carries forward.
     #
     collect_3x = Puppet::Pops::Model::AstTransformer.new().transform(o)
     collected = collect_3x.evaluate(scope)
     # the 3x returns an instance of Parser::Collector (but it is only registered with the compiler at this
     # point and does not contain any valuable information (like the result)
     # Dilemma: If this object is returned, it is a first class value in the Puppet Language and we
     # need to be able to perform operations on it. We can forbid it from leaking by making CollectExpression
     # a non R-value. This makes it possible for the evaluator logic to make use of the Collector.
     collected
   end
 
   def eval_ParenthesizedExpression(o, scope)
     evaluate(o.expr, scope)
   end
 
   # This evaluates classes, nodes and resource type definitions to nil, since 3x:
   # instantiates them, and evaluates their parameters and body. This is achieved by
   # providing bridge AST classes in Puppet::Parser::AST::PopsBridge that bridges a
   # Pops Program and a Pops Expression.
   #
   # Since all Definitions are handled "out of band", they are treated as a no-op when
   # evaluated.
   #
   def eval_Definition(o, scope)
     nil
   end
 
   def eval_Program(o, scope)
     evaluate(o.body, scope)
   end
 
   # Produces Array[PObjectType], an array of resource references
   #
   def eval_ResourceExpression(o, scope)
     exported = o.exported
     virtual = o.virtual
     type_name = evaluate(o.type_name, scope)
     o.bodies.map do |body|
       titles = [evaluate(body.title, scope)].flatten
       evaluated_parameters = body.operations.map {|op| evaluate(op, scope) }
       create_resources(o, scope, virtual, exported, type_name, titles, evaluated_parameters)
     end.flatten.compact
   end
 
   def eval_ResourceOverrideExpression(o, scope)
     evaluated_resources = evaluate(o.resources, scope)
     evaluated_parameters = o.operations.map { |op| evaluate(op, scope) }
     create_resource_overrides(o, scope, [evaluated_resources].flatten, evaluated_parameters)
     evaluated_resources
   end
 
   # Produces 3x array of parameters
   def eval_AttributeOperation(o, scope)
     create_resource_parameter(o, scope, o.attribute_name, evaluate(o.value_expr, scope), o.operator)
   end
 
   # Sets default parameter values for a type, produces the type
   #
   def eval_ResourceDefaultsExpression(o, scope)
     type_name = o.type_ref.value # a QualifiedName's string value
     evaluated_parameters = o.operations.map {|op| evaluate(op, scope) }
     create_resource_defaults(o, scope, type_name, evaluated_parameters)
     # Produce the type
     evaluate(o.type_ref, scope)
   end
 
   # Evaluates function call by name.
   #
   def eval_CallNamedFunctionExpression(o, scope)
     # The functor expression is not evaluated, it is not possible to select the function to call
     # via an expression like $a()
     case o.functor_expr
     when Puppet::Pops::Model::QualifiedName
       # ok
     when Puppet::Pops::Model::RenderStringExpression
       # helpful to point out this easy to make Epp error
       fail(Issues::ILLEGAL_EPP_PARAMETERS, o)
     else
       fail(Issues::ILLEGAL_EXPRESSION, o.functor_expr, {:feature=>'function name', :container => o})
     end
     name = o.functor_expr.value
     evaluated_arguments = o.arguments.collect {|arg| evaluate(arg, scope) }
     # wrap lambda in a callable block if it is present
     evaluated_arguments << Puppet::Pops::Evaluator::Closure.new(self, o.lambda, scope) if o.lambda
     call_function(name, evaluated_arguments, o, scope)
   end
 
   # Evaluation of CallMethodExpression handles a NamedAccessExpression functor (receiver.function_name)
   #
   def eval_CallMethodExpression(o, scope)
     unless o.functor_expr.is_a? Puppet::Pops::Model::NamedAccessExpression
       fail(Issues::ILLEGAL_EXPRESSION, o.functor_expr, {:feature=>'function accessor', :container => o})
     end
     receiver = evaluate(o.functor_expr.left_expr, scope)
     name = o.functor_expr.right_expr
     unless name.is_a? Puppet::Pops::Model::QualifiedName
       fail(Issues::ILLEGAL_EXPRESSION, o.functor_expr, {:feature=>'function name', :container => o})
     end 
     name = name.value # the string function name
     evaluated_arguments = [receiver] + (o.arguments || []).collect {|arg| evaluate(arg, scope) }
     evaluated_arguments << Puppet::Pops::Evaluator::Closure.new(self, o.lambda, scope) if o.lambda
     call_function(name, evaluated_arguments, o, scope)
   end
 
   # @example
   #   $x ? { 10 => true, 20 => false, default => 0 }
   #
   def eval_SelectorExpression o, scope
     # memo scope level before evaluating test - don't want a match in the case test to leak $n match vars
     # to expressions after the selector expression.
     #
     with_guarded_scope(scope) do
       test = evaluate(o.left_expr, scope)
       selected = o.selectors.find do |s|
         candidate = evaluate(s.matching_expr, scope)
         candidate == :default || is_match?(test, candidate, s.matching_expr, scope)
       end
       if selected
         evaluate(selected.value_expr, scope)
       else
         nil
       end
     end
   end
 
   # SubLocatable is simply an expression that holds location information
   def eval_SubLocatedExpression o, scope
     evaluate(o.expr, scope)
   end
 
   # Evaluates Puppet DSL Heredoc
   def eval_HeredocExpression o, scope
     result = evaluate(o.text_expr, scope)
     assert_external_syntax(scope, result, o.syntax, o.text_expr)
     result
   end
 
   # Evaluates Puppet DSL `if`
   def eval_IfExpression o, scope
     with_guarded_scope(scope) do
       if is_true?(evaluate(o.test, scope))
         evaluate(o.then_expr, scope)
       else
         evaluate(o.else_expr, scope)
       end
     end
   end
 
   # Evaluates Puppet DSL `unless`
   def eval_UnlessExpression o, scope
     with_guarded_scope(scope) do
       unless is_true?(evaluate(o.test, scope))
         evaluate(o.then_expr, scope)
       else
         evaluate(o.else_expr, scope)
       end
     end
   end
 
   # Evaluates a variable (getting its value)
   # The evaluator is lenient; any expression producing a String is used as a name
   # of a variable.
   #
   def eval_VariableExpression o, scope
     # Evaluator is not too fussy about what constitutes a name as long as the result
     # is a String and a valid variable name
     #
     name = evaluate(o.expr, scope)
 
     # Should be caught by validation, but make this explicit here as well, or mysterious evaluation issues
     # may occur.
     case name
     when String
     when Numeric
     else
       fail(Issues::ILLEGAL_VARIABLE_EXPRESSION, o.expr)
     end
     # TODO: Check for valid variable name (Task for validator)
     # TODO: semantics of undefined variable in scope, this just returns what scope does == value or nil
     get_variable_value(name, o, scope)
   end
 
   # Evaluates double quoted strings that may contain interpolation
   #
   def eval_ConcatenatedString o, scope
     o.segments.collect {|expr| string(evaluate(expr, scope), scope)}.join
   end
 
 
   # If the wrapped expression is a QualifiedName, it is taken as the name of a variable in scope.
   # Note that this is different from the 3.x implementation, where an initial qualified name
   # is accepted. (e.g. `"---${var + 1}---"` is legal. This implementation requires such concrete
   # syntax to be expressed in a model as `(TextExpression (+ (Variable var) 1)` - i.e. moving the decision to
   # the parser.
   #
   # Semantics; the result of an expression is turned into a string, nil is silently transformed to empty
   # string.
   # @return [String] the interpolated result
   #
   def eval_TextExpression o, scope
     if o.expr.is_a?(Puppet::Pops::Model::QualifiedName)
       # TODO: formalize, when scope returns nil, vs error
       string(get_variable_value(o.expr.value, o, scope), scope)
     else
       string(evaluate(o.expr, scope), scope)
     end
   end
 
   def string_Object(o, scope)
     o.to_s
   end
 
   def string_Symbol(o, scope)
     case o
     when :undef
       ''
     else
       o.to_s
     end
   end
 
   def string_Array(o, scope) 
     ['[', o.map {|e| string(e, scope)}.join(', '), ']'].join()
   end
 
   def string_Hash(o, scope)
     ['{', o.map {|k,v| string(k, scope) + " => " + string(v, scope)}.join(', '), '}'].join()
   end
 
   def string_Regexp(o, scope)
     ['/', o.source, '/'].join()
   end
 
   def string_PAbstractType(o, scope)
     @@type_calculator.string(o)
   end
 
   # Produces concatenation / merge of x and y.
   #
   # When x is an Array, y of type produces:
   #
   # * Array => concatenation `[1,2], [3,4] => [1,2,3,4]`
   # * Hash => concatenation of hash as array `[key, value, key, value, ...]`
   # * any other => concatenation of single value
   #
   # When x is a Hash, y of type produces:
   #
   # * Array => merge of array interpreted as `[key, value, key, value,...]`
   # * Hash => a merge, where entries in `y` overrides
   # * any other => error
   #
   # When x is something else, wrap it in an array first.
   #
   # When x is nil, an empty array is used instead.
   #
   # @note to concatenate an Array, nest the array - i.e. `[1,2], [[2,3]]`
   #
   # @overload concatenate(obj_x, obj_y)
   #   @param obj_x [Object] object to wrap in an array and concatenate to; see other overloaded methods for return type
   #   @param ary_y [Object] array to concatenate at end of `ary_x`
   #   @return [Object] wraps obj_x in array before using other overloaded option based on type of obj_y
   # @overload concatenate(ary_x, ary_y)
   #   @param ary_x [Array] array to concatenate to
   #   @param ary_y [Array] array to concatenate at end of `ary_x`
   #   @return [Array] new array with `ary_x` + `ary_y`
   # @overload concatenate(ary_x, hsh_y)
   #   @param ary_x [Array] array to concatenate to
   #   @param hsh_y [Hash] converted to array form, and concatenated to array
   #   @return [Array] new array with `ary_x` + `hsh_y` converted to array
   # @overload concatenate (ary_x, obj_y)
   #   @param ary_x [Array] array to concatenate to
   #   @param obj_y [Object] non array or hash object to add to array
   #   @return [Array] new array with `ary_x` + `obj_y` added as last entry
   # @overload concatenate(hsh_x, ary_y)
   #   @param hsh_x [Hash] the hash to merge with
   #   @param ary_y [Array] array interpreted as even numbered sequence of key, value merged with `hsh_x`
   #   @return [Hash] new hash with `hsh_x` merged with `ary_y` interpreted as hash in array form
   # @overload concatenate(hsh_x, hsh_y)
   #   @param hsh_x [Hash] the hash to merge to
   #   @param hsh_y [Hash] hash merged with `hsh_x`
   #   @return [Hash] new hash with `hsh_x` merged with `hsh_y`
   # @raise [ArgumentError] when `xxx_x` is neither an Array nor a Hash
   # @raise [ArgumentError] when `xxx_x` is a Hash, and `xxx_y` is neither Array nor Hash.
   #
   def concatenate(x, y)
     x = [x] unless x.is_a?(Array) || x.is_a?(Hash)
     case x
     when Array
       y = case y
       when Array then y
       when Hash  then y.to_a
       else
         [y]
       end
       x + y # new array with concatenation
     when Hash
       y = case y
       when Hash then y
       when Array
         # Hash[[a, 1, b, 2]] => {}
         # Hash[a,1,b,2] => {a => 1, b => 2}
         # Hash[[a,1], [b,2]] => {[a,1] => [b,2]}
         # Hash[[[a,1], [b,2]]] => {a => 1, b => 2}
         # Use type calcultor to determine if array is Array[Array[?]], and if so use second form
         # of call
         t = @@type_calculator.infer(y)
         if t.element_type.is_a? Puppet::Pops::Types::PArrayType
           Hash[y]
         else
           Hash[*y]
         end
       else
         raise ArgumentError.new("Can only append Array or Hash to a Hash")
       end
       x.merge y # new hash with overwrite
     else
       raise ArgumentError.new("Can only append to an Array or a Hash.")
     end
   end
 
   # Produces the result x \ y (set difference)
   # When `x` is an Array, `y` is transformed to an array and then all matching elements removed from x.
   # When `x` is a Hash, all contained keys are removed from x as listed in `y` if it is an Array, or all its keys if it is a Hash.
   # The difference is returned. The given `x` and `y` are not modified by this operation.
   # @raise [ArgumentError] when `x` is neither an Array nor a Hash
   #
   def delete(x, y)
     result = x.dup
     case x
     when Array
       y = case y
       when Array then y
       when Hash then y.to_a
       else
         [y]
       end
       y.each {|e| result.delete(e) }
     when Hash
       y = case y
       when Array then y
       when Hash then y.keys
       else
         [y]
       end
       y.each {|e| result.delete(e) }
     else
       raise ArgumentError.new("Can only delete from an Array or Hash.")
     end
     result
   end
 
   # Implementation of case option matching.
   #
   # This is the type of matching performed in a case option, using == for every type
   # of value except regular expression where a match is performed.
   #
   def is_match? left, right, o, scope
     if right.is_a?(Regexp)
       return false unless left.is_a? String
       matched = right.match(left)
       set_match_data(matched, o, scope) # creates or clears ephemeral
       !!matched # convert to boolean
     elsif right.is_a?(Puppet::Pops::Types::PAbstractType)
       # right is a type and left is not - check if left is an instance of the given type
       # (The reverse is not terribly meaningful - computing which of the case options that first produces
       # an instance of a given type).
       #
       @@type_calculator.instance?(right, left)
     else
       # Handle equality the same way as the language '==' operator (case insensitive etc.)
       @@compare_operator.equals(left,right)
     end
   end
 
   def with_guarded_scope(scope)
     scope_memo = get_scope_nesting_level(scope)
     begin
       yield
     ensure
       set_scope_nesting_level(scope, scope_memo)
     end
   end
 
 end
diff --git a/spec/unit/parser/methods/map_spec.rb b/spec/unit/parser/methods/map_spec.rb
index 7f8e79789..08f4cd124 100644
--- a/spec/unit/parser/methods/map_spec.rb
+++ b/spec/unit/parser/methods/map_spec.rb
@@ -1,184 +1,196 @@
 require 'puppet'
 require 'spec_helper'
 require 'puppet_spec/compiler'
 
 require 'unit/parser/methods/shared'
 
 describe 'the map method' do
   include PuppetSpec::Compiler
 
   before :each do
     Puppet[:parser] = "future"
   end
 
   context "using future parser" do
     it 'map on an array (multiplying each value by 2)' do
       catalog = compile_to_catalog(<<-MANIFEST)
         $a = [1,2,3]
         $a.map |$x|{ $x*2}.each |$v|{
           file { "/file_$v": ensure => present }
         }
       MANIFEST
 
       catalog.resource(:file, "/file_2")['ensure'].should == 'present'
       catalog.resource(:file, "/file_4")['ensure'].should == 'present'
       catalog.resource(:file, "/file_6")['ensure'].should == 'present'
     end
 
     it 'map on an enumerable type (multiplying each value by 2)' do
       catalog = compile_to_catalog(<<-MANIFEST)
         $a = Integer[1,3]
         $a.map |$x|{ $x*2}.each |$v|{
           file { "/file_$v": ensure => present }
         }
       MANIFEST
 
       catalog.resource(:file, "/file_2")['ensure'].should == 'present'
       catalog.resource(:file, "/file_4")['ensure'].should == 'present'
       catalog.resource(:file, "/file_6")['ensure'].should == 'present'
     end
 
     it 'map on an integer (multiply each by 3)' do
       catalog = compile_to_catalog(<<-MANIFEST)
         3.map |$x|{ $x*3}.each |$v|{
           file { "/file_$v": ensure => present }
         }
       MANIFEST
 
       catalog.resource(:file, "/file_0")['ensure'].should == 'present'
       catalog.resource(:file, "/file_3")['ensure'].should == 'present'
       catalog.resource(:file, "/file_6")['ensure'].should == 'present'
     end
 
     it 'map on a string' do
       catalog = compile_to_catalog(<<-MANIFEST)
         $a = {a=>x, b=>y}
         "ab".map |$x|{$a[$x]}.each |$v|{
           file { "/file_$v": ensure => present }
         }
       MANIFEST
 
       catalog.resource(:file, "/file_x")['ensure'].should == 'present'
       catalog.resource(:file, "/file_y")['ensure'].should == 'present'
     end
 
     it 'map on an array (multiplying value by 10 in even index position)' do
       catalog = compile_to_catalog(<<-MANIFEST)
         $a = [1,2,3]
         $a.map |$i, $x|{ if $i % 2 == 0 {$x} else {$x*10}}.each |$v|{
           file { "/file_$v": ensure => present }
         }
       MANIFEST
 
       catalog.resource(:file, "/file_1")['ensure'].should == 'present'
       catalog.resource(:file, "/file_20")['ensure'].should == 'present'
       catalog.resource(:file, "/file_3")['ensure'].should == 'present'
     end
 
     it 'map on a hash selecting keys' do
       catalog = compile_to_catalog(<<-MANIFEST)
       $a = {'a'=>1,'b'=>2,'c'=>3}
       $a.map |$x|{ $x[0]}.each |$k|{
           file { "/file_$k": ensure => present }
         }
       MANIFEST
 
       catalog.resource(:file, "/file_a")['ensure'].should == 'present'
       catalog.resource(:file, "/file_b")['ensure'].should == 'present'
       catalog.resource(:file, "/file_c")['ensure'].should == 'present'
     end
 
     it 'map on a hash selecting keys - using two block parameters' do
       catalog = compile_to_catalog(<<-MANIFEST)
       $a = {'a'=>1,'b'=>2,'c'=>3}
       $a.map |$k,$v|{ file { "/file_$k": ensure => present }
         }
       MANIFEST
 
       catalog.resource(:file, "/file_a")['ensure'].should == 'present'
       catalog.resource(:file, "/file_b")['ensure'].should == 'present'
       catalog.resource(:file, "/file_c")['ensure'].should == 'present'
     end
 
     it 'each on a hash selecting value' do
       catalog = compile_to_catalog(<<-MANIFEST)
       $a = {'a'=>1,'b'=>2,'c'=>3}
       $a.map |$x|{ $x[1]}.each |$k|{ file { "/file_$k": ensure => present } }
       MANIFEST
 
       catalog.resource(:file, "/file_1")['ensure'].should == 'present'
       catalog.resource(:file, "/file_2")['ensure'].should == 'present'
       catalog.resource(:file, "/file_3")['ensure'].should == 'present'
     end
 
     it 'each on a hash selecting value - using two bloc parameters' do
       catalog = compile_to_catalog(<<-MANIFEST)
       $a = {'a'=>1,'b'=>2,'c'=>3}
       $a.map |$k,$v|{ file { "/file_$v": ensure => present } }
       MANIFEST
 
       catalog.resource(:file, "/file_1")['ensure'].should == 'present'
       catalog.resource(:file, "/file_2")['ensure'].should == 'present'
       catalog.resource(:file, "/file_3")['ensure'].should == 'present'
     end
 
     context "handles data type corner cases" do
       it "map gets values that are false" do
         catalog = compile_to_catalog(<<-MANIFEST)
           $a = [false,false]
           $a.map |$x| { $x }.each |$i, $v| {
             file { "/file_$i.$v": ensure => present }
           }
         MANIFEST
 
         catalog.resource(:file, "/file_0.false")['ensure'].should == 'present'
         catalog.resource(:file, "/file_1.false")['ensure'].should == 'present'
       end
 
       it "map gets values that are nil" do
         Puppet::Parser::Functions.newfunction(:nil_array, :type => :rvalue) do |args|
           [nil]
         end
         catalog = compile_to_catalog(<<-MANIFEST)
           $a = nil_array()
           $a.map |$x| { $x }.each |$i, $v| {
             file { "/file_$i.$v": ensure => present }
           }
         MANIFEST
 
         catalog.resource(:file, "/file_0.")['ensure'].should == 'present'
       end
 
       it "map gets values that are undef" do
+        pending "Test is flawed, but has good intentions - should be rewritten when map has moved to new func API"
+        # The test is broken because:
+        # - a bug caused the given value to always be overridden by a given lambda default
+        # - non existing variable results in nil / undef, which is transformed to empty string in the 3x func API
+        # - when lambda is called, it gets an empty string, and it is then expected to use the default value
+        #
+        # This is not the semantics we want (only missing argument should trigger the default value).
+        # Finally, it is not possible to test missing arguments with the map function since the call adapts itself
+        # to the number of lambda parameters. (There is testing of this elsewhere).
+        #
+        # TODO: Rewrite map function, then test that undef / nil values are passed correctly to the lambda
+        #
         catalog = compile_to_catalog(<<-MANIFEST)
           $a = [$does_not_exist]
           $a.map |$x = "something"| { $x }.each |$i, $v| {
             file { "/file_$i.$v": ensure => present }
           }
         MANIFEST
         catalog.resource(:file, "/file_0.something")['ensure'].should == 'present'
       end
     end
 
   context 'map checks arguments and' do
     it 'raises an error when block has more than 2 argument' do
       expect do
         compile_to_catalog(<<-MANIFEST)
           [1].map |$index, $x, $yikes|{  }
         MANIFEST
       end.to raise_error(Puppet::Error, /block must define at most two parameters/)
     end
 
     it 'raises an error when block has fewer than 1 argument' do
       expect do
         compile_to_catalog(<<-MANIFEST)
           [1].map || {  }
         MANIFEST
       end.to raise_error(Puppet::Error, /block must define at least one parameter/)
     end
   end
 
   it_should_behave_like 'all iterative functions argument checks', 'map'
   it_should_behave_like 'all iterative functions hash handling', 'map'
   end
 end
diff --git a/spec/unit/pops/evaluator/evaluating_parser_spec.rb b/spec/unit/pops/evaluator/evaluating_parser_spec.rb
index 0a8d90337..0cd9939f2 100644
--- a/spec/unit/pops/evaluator/evaluating_parser_spec.rb
+++ b/spec/unit/pops/evaluator/evaluating_parser_spec.rb
@@ -1,1056 +1,1096 @@
 require 'spec_helper'
 
 require 'puppet/pops'
 require 'puppet/pops/evaluator/evaluator_impl'
+require 'puppet/loaders'
 require 'puppet_spec/pops'
 require 'puppet_spec/scope'
 require 'puppet/parser/e4_parser_adapter'
 
 
 # relative to this spec file (./) does not work as this file is loaded by rspec
 #require File.join(File.dirname(__FILE__), '/evaluator_rspec_helper')
 
 describe 'Puppet::Pops::Evaluator::EvaluatorImpl' do
   include PuppetSpec::Pops
   include PuppetSpec::Scope
   before(:each) do
     Puppet[:strict_variables] = true
 
     # These must be set since the is 3x logic that triggers on these even if the tests are explicit
     # about selection of parser and evaluator
     #
     Puppet[:parser] = 'future'
     Puppet[:evaluator] = 'future'
     # Puppetx cannot be loaded until the correct parser has been set (injector is turned off otherwise)
     require 'puppetx'
   end
 
   let(:parser) {  Puppet::Pops::Parser::EvaluatingParser::Transitional.new }
   let(:node) { 'node.example.com' }
   let(:scope) { s = create_test_scope_for_node(node); s }
   types = Puppet::Pops::Types::TypeFactory
 
   context "When evaluator evaluates literals" do
     {
       "1"             => 1,
       "010"           => 8,
       "0x10"          => 16,
       "3.14"          => 3.14,
       "0.314e1"       => 3.14,
       "31.4e-1"       => 3.14,
       "'1'"           => '1',
       "'banana'"      => 'banana',
       '"banana"'      => 'banana',
       "banana"        => 'banana',
       "banana::split" => 'banana::split',
       "false"         => false,
       "true"          => true,
       "Array"         => types.array_of_data(),
       "/.*/"          => /.*/
     }.each do |source, result|
         it "should parse and evaluate the expression '#{source}' to #{result}" do
           parser.evaluate_string(scope, source, __FILE__).should == result
         end
       end
   end
 
   context "When the evaluator evaluates Lists and Hashes" do
     {
       "[]"                                              => [],
       "[1,2,3]"                                         => [1,2,3],
       "[1,[2.0, 2.1, [2.2]],[3.0, 3.1]]"                => [1,[2.0, 2.1, [2.2]],[3.0, 3.1]],
       "[2 + 2]"                                         => [4],
       "[1,2,3] == [1,2,3]"                              => true,
       "[1,2,3] != [2,3,4]"                              => true,
       "[1,2,3] == [2,2,3]"                              => false,
       "[1,2,3] != [1,2,3]"                              => false,
       "[1,2,3][2]"                                      => 3,
       "[1,2,3] + [4,5]"                                 => [1,2,3,4,5],
       "[1,2,3] + [[4,5]]"                               => [1,2,3,[4,5]],
       "[1,2,3] + 4"                                     => [1,2,3,4],
       "[1,2,3] << [4,5]"                                => [1,2,3,[4,5]],
       "[1,2,3] << {'a' => 1, 'b'=>2}"                   => [1,2,3,{'a' => 1, 'b'=>2}],
       "[1,2,3] << 4"                                    => [1,2,3,4],
       "[1,2,3,4] - [2,3]"                               => [1,4],
       "[1,2,3,4] - [2,5]"                               => [1,3,4],
       "[1,2,3,4] - 2"                                   => [1,3,4],
       "[1,2,3,[2],4] - 2"                               => [1,3,[2],4],
       "[1,2,3,[2,3],4] - [[2,3]]"                       => [1,2,3,4],
       "[1,2,3,3,2,4,2,3] - [2,3]"                       => [1,4],
       "[1,2,3,['a',1],['b',2]] - {'a' => 1, 'b'=>2}"    => [1,2,3],
       "[1,2,3,{'a'=>1,'b'=>2}] - [{'a' => 1, 'b'=>2}]"  => [1,2,3],
     }.each do |source, result|
         it "should parse and evaluate the expression '#{source}' to #{result}" do
           parser.evaluate_string(scope, source, __FILE__).should == result
         end
       end
 
     {
       "[1,2,3] + {'a' => 1, 'b'=>2}"                    => [1,2,3,['a',1],['b',2]],
     }.each do |source, result|
         it "should parse and evaluate the expression '#{source}' to #{result}" do
           # This test must be done with match_array since the order of the hash
           # is undefined and Ruby 1.8.7 and 1.9.3 produce different results.
           expect(parser.evaluate_string(scope, source, __FILE__)).to match_array(result)
         end
       end
 
     {
       "[1,2,3][a]" => :error,
     }.each do |source, result|
         it "should parse and raise error for '#{source}'" do
           expect { parser.evaluate_string(scope, source, __FILE__) }.to raise_error(Puppet::ParseError)
         end
       end
 
     {
       "{}"                                       => {},
       "{'a'=>1,'b'=>2}"                          => {'a'=>1,'b'=>2},
       "{'a'=>1,'b'=>{'x'=>2.1,'y'=>2.2}}"        => {'a'=>1,'b'=>{'x'=>2.1,'y'=>2.2}},
       "{'a'=> 2 + 2}"                            => {'a'=> 4},
       "{'a'=> 1, 'b'=>2} == {'a'=> 1, 'b'=>2}"   => true,
       "{'a'=> 1, 'b'=>2} != {'x'=> 1, 'b'=>2}"   => true,
       "{'a'=> 1, 'b'=>2} == {'a'=> 2, 'b'=>3}"   => false,
       "{'a'=> 1, 'b'=>2} != {'a'=> 1, 'b'=>2}"   => false,
       "{a => 1, b => 2}[b]"                      => 2,
       "{2+2 => sum, b => 2}[4]"                  => 'sum',
       "{'a'=>1, 'b'=>2} + {'c'=>3}"              => {'a'=>1,'b'=>2,'c'=>3},
       "{'a'=>1, 'b'=>2} + {'b'=>3}"              => {'a'=>1,'b'=>3},
       "{'a'=>1, 'b'=>2} + ['c', 3, 'b', 3]"      => {'a'=>1,'b'=>3, 'c'=>3},
       "{'a'=>1, 'b'=>2} + [['c', 3], ['b', 3]]"  => {'a'=>1,'b'=>3, 'c'=>3},
       "{'a'=>1, 'b'=>2} - {'b' => 3}"            => {'a'=>1},
       "{'a'=>1, 'b'=>2, 'c'=>3} - ['b', 'c']"    => {'a'=>1},
       "{'a'=>1, 'b'=>2, 'c'=>3} - 'c'"           => {'a'=>1, 'b'=>2},
     }.each do |source, result|
         it "should parse and evaluate the expression '#{source}' to #{result}" do
           parser.evaluate_string(scope, source, __FILE__).should == result
         end
       end
 
     {
       "{'a' => 1, 'b'=>2} << 1" => :error,
     }.each do |source, result|
         it "should parse and raise error for '#{source}'" do
           expect { parser.evaluate_string(scope, source, __FILE__) }.to raise_error(Puppet::ParseError)
         end
       end
   end
 
   context "When the evaluator perform comparisons" do
     {
       "'a' == 'a'"     => true,
       "'a' == 'b'"     => false,
       "'a' != 'a'"     => false,
       "'a' != 'b'"     => true,
       "'a' < 'b' "     => true,
       "'a' < 'a' "     => false,
       "'b' < 'a' "     => false,
       "'a' <= 'b'"     => true,
       "'a' <= 'a'"     => true,
       "'b' <= 'a'"     => false,
       "'a' > 'b' "     => false,
       "'a' > 'a' "     => false,
       "'b' > 'a' "     => true,
       "'a' >= 'b'"     => false,
       "'a' >= 'a'"     => true,
       "'b' >= 'a'"     => true,
       "'a' == 'A'"     => true,
       "'a' != 'A'"     => false,
       "'a' >  'A'"     => false,
       "'a' >= 'A'"     => true,
       "'A' <  'a'"     => false,
       "'A' <= 'a'"     => true,
       "1 == 1"         => true,
       "1 == 2"         => false,
       "1 != 1"         => false,
       "1 != 2"         => true,
       "1 < 2 "         => true,
       "1 < 1 "         => false,
       "2 < 1 "         => false,
       "1 <= 2"         => true,
       "1 <= 1"         => true,
       "2 <= 1"         => false,
       "1 > 2 "         => false,
       "1 > 1 "         => false,
       "2 > 1 "         => true,
       "1 >= 2"         => false,
       "1 >= 1"         => true,
       "2 >= 1"         => true,
       "1 == 1.0 "      => true,
       "1 < 1.1  "      => true,
       "'1' < 1.1"      => true,
       "1.0 == 1 "      => true,
       "1.0 < 2  "      => true,
       "1.0 < 'a'"      => true,
       "'1.0' < 1.1"    => true,
       "'1.0' < 'a'"    => true,
       "'1.0' < '' "    => true,
       "'1.0' < ' '"    => true,
       "'a' > '1.0'"    => true,
       "/.*/ == /.*/ "  => true,
       "/.*/ != /a.*/"  => true,
       "true  == true " => true,
       "false == false" => true,
       "true == false"  => false,
     }.each do |source, result|
         it "should parse and evaluate the expression '#{source}' to #{result}" do
           parser.evaluate_string(scope, source, __FILE__).should == result
         end
       end
 
    {
       "'a' =~ /.*/"                     => true,
       "'a' =~ '.*'"                     => true,
       "/.*/ != /a.*/"                   => true,
       "'a' !~ /b.*/"                    => true,
       "'a' !~ 'b.*'"                    => true,
       '$x = a; a =~ "$x.*"'             => true,
       "a =~ Pattern['a.*']"             => true,
       "a =~ Regexp['a.*']"              => true,
       "$x = /a.*/ a =~ $x"              => true,
       "$x = Pattern['a.*'] a =~ $x"     => true,
       "1 =~ Integer"                    => true,
       "1 !~ Integer"                    => false,
       "[1,2,3] =~ Array[Integer[1,10]]" => true,
     }.each do |source, result|
         it "should parse and evaluate the expression '#{source}' to #{result}" do
           parser.evaluate_string(scope, source, __FILE__).should == result
         end
       end
 
     {
       "666 =~ /6/"    => :error,
       "[a] =~ /a/"    => :error,
       "{a=>1} =~ /a/" => :error,
        "/a/ =~ /a/"    => :error,
       "Array =~ /A/"  => :error,
     }.each do |source, result|
         it "should parse and raise error for '#{source}'" do
           expect { parser.evaluate_string(scope, source, __FILE__) }.to raise_error(Puppet::ParseError)
         end
       end
 
     {
       "1 in [1,2,3]"                  => true,
       "4 in [1,2,3]"                  => false,
       "a in {x=>1, a=>2}"             => true,
       "z in {x=>1, a=>2}"             => false,
       "ana in bananas"                => true,
       "xxx in bananas"                => false,
       "/ana/ in bananas"              => true,
       "/xxx/ in bananas"              => false,
       "ANA in bananas"                => false, # ANA is a type, not a String
       "'ANA' in bananas"              => true,
       "ana in 'BANANAS'"              => true,
       "/ana/ in 'BANANAS'"            => false,
       "/ANA/ in 'BANANAS'"            => true,
       "xxx in 'BANANAS'"              => false,
       "[2,3] in [1,[2,3],4]"          => true,
       "[2,4] in [1,[2,3],4]"          => false,
       "[a,b] in ['A',['A','B'],'C']"  => true,
       "[x,y] in ['A',['A','B'],'C']"  => false,
       "a in {a=>1}"                   => true,
       "x in {a=>1}"                   => false,
       "'A' in {a=>1}"                 => true,
       "'X' in {a=>1}"                 => false,
       "a in {'A'=>1}"                 => true,
       "x in {'A'=>1}"                 => false,
       "/xxx/ in {'aaaxxxbbb'=>1}"     => true,
       "/yyy/ in {'aaaxxxbbb'=>1}"     => false,
       "15 in [1, 0xf]"                => true,
       "15 in [1, '0xf']"              => true,
       "'15' in [1, 0xf]"              => true,
       "15 in [1, 115]"                => false,
       "1 in [11, '111']"              => false,
       "'1' in [11, '111']"            => false,
       "Array[Integer] in [2, 3]"      => false,
       "Array[Integer] in [2, [3, 4]]" => true,
       "Array[Integer] in [2, [a, 4]]" => false,
       "Integer in { 2 =>'a'}"         => true,
       "Integer[5,10] in [1,5,3]"      => true,
       "Integer[5,10] in [1,2,3]"      => false,
       "Integer in {'a'=>'a'}"         => false,
       "Integer in {'a'=>1}"           => false,
     }.each do |source, result|
       it "should parse and evaluate the expression '#{source}' to #{result}" do
         parser.evaluate_string(scope, source, __FILE__).should == result
       end
     end
 
     {
       'Object'  => ['Data', 'Scalar', 'Numeric', 'Integer', 'Float', 'Boolean', 'String', 'Pattern', 'Collection',
                     'Array', 'Hash', 'CatalogEntry', 'Resource', 'Class', 'Undef', 'File', 'NotYetKnownResourceType'],
 
       # Note, Data > Collection is false (so not included)
       'Data'    => ['Scalar', 'Numeric', 'Integer', 'Float', 'Boolean', 'String', 'Pattern', 'Array', 'Hash',],
       'Scalar' => ['Numeric', 'Integer', 'Float', 'Boolean', 'String', 'Pattern'],
       'Numeric' => ['Integer', 'Float'],
       'CatalogEntry' => ['Class', 'Resource', 'File', 'NotYetKnownResourceType'],
       'Integer[1,10]' => ['Integer[2,3]'],
     }.each do |general, specials|
       specials.each do |special |
         it "should compute that #{general} > #{special}" do
           parser.evaluate_string(scope, "#{general} > #{special}", __FILE__).should == true
         end
         it "should compute that  #{special} < #{general}" do
           parser.evaluate_string(scope, "#{special} < #{general}", __FILE__).should == true
         end
         it "should compute that #{general} != #{special}" do
           parser.evaluate_string(scope, "#{special} != #{general}", __FILE__).should == true
         end
       end
     end
 
     {
       'Integer[1,10] > Integer[2,3]'   => true,
       'Integer[1,10] == Integer[2,3]'  => false,
       'Integer[1,10] > Integer[0,5]'   => false,
       'Integer[1,10] > Integer[1,10]'  => false,
       'Integer[1,10] >= Integer[1,10]' => true,
       'Integer[1,10] == Integer[1,10]' => true,
     }.each do |source, result|
         it "should parse and evaluate the integer range comparison expression '#{source}' to #{result}" do
           parser.evaluate_string(scope, source, __FILE__).should == result
         end
       end
 
   end
 
   context "When the evaluator performs arithmetic" do
     context "on Integers" do
       {  "2+2"    => 4,
          "2 + 2"  => 4,
          "7 - 3"  => 4,
          "6 * 3"  => 18,
          "6 / 3"  => 2,
          "6 % 3"  => 0,
          "10 % 3" =>  1,
          "-(6/3)" => -2,
          "-6/3  " => -2,
          "8 >> 1" => 4,
          "8 << 1" => 16,
       }.each do |source, result|
           it "should parse and evaluate the expression '#{source}' to #{result}" do
             parser.evaluate_string(scope, source, __FILE__).should == result
           end
         end
 
     context "on Floats" do
       {
         "2.2 + 2.2"  => 4.4,
         "7.7 - 3.3"  => 4.4,
         "6.1 * 3.1"  => 18.91,
         "6.6 / 3.3"  => 2.0,
         "-(6.0/3.0)" => -2.0,
         "-6.0/3.0 "  => -2.0,
       }.each do |source, result|
           it "should parse and evaluate the expression '#{source}' to #{result}" do
             parser.evaluate_string(scope, source, __FILE__).should == result
           end
         end
 
       {
         "3.14 << 2" => :error,
         "3.14 >> 2" => :error,
         "6.6 % 3.3"  => 0.0,
         "10.0 % 3.0" =>  1.0,
       }.each do |source, result|
           it "should parse and raise error for '#{source}'" do
             expect { parser.evaluate_string(scope, source, __FILE__) }.to raise_error(Puppet::ParseError)
           end
         end
     end
 
     context "on strings requiring boxing to Numeric" do
       {
         "'2' + '2'"       => 4,
         "'2.2' + '2.2'"   => 4.4,
         "'0xF7' + '010'"  => 0xFF,
         "'0xF7' + '0x8'"  => 0xFF,
         "'0367' + '010'"  => 0xFF,
         "'012.3' + '010'" => 20.3,
       }.each do |source, result|
           it "should parse and evaluate the expression '#{source}' to #{result}" do
             parser.evaluate_string(scope, source, __FILE__).should == result
           end
         end
 
       {
         "'0888' + '010'"   => :error,
         "'0xWTF' + '010'"  => :error,
         "'0x12.3' + '010'" => :error,
         "'0x12.3' + '010'" => :error,
       }.each do |source, result|
           it "should parse and raise error for '#{source}'" do
             expect { parser.evaluate_string(scope, source, __FILE__) }.to raise_error(Puppet::ParseError)
           end
         end
       end
     end
   end # arithmetic
 
   context "When the evaluator evaluates assignment" do
     {
       "$a = 5"                     => 5,
       "$a = 5; $a"                 => 5,
       "$a = 5; $b = 6; $a"         => 5,
       "$a = $b = 5; $a == $b"      => true,
       "$a = [1,2,3]; [x].map |$x| { $a += x; $a }"      => [[1,2,3,'x']],
       "$a = [a,x,c]; [x].map |$x| { $a -= x; $a }"      => [['a','c']],
     }.each do |source, result|
         it "should parse and evaluate the expression '#{source}' to #{result}" do
           parser.evaluate_string(scope, source, __FILE__).should == result
         end
       end
 
     {
       "[a,b,c] = [1,2,3]; $a == 1 and $b == 2 and $c == 3"               => :error,
       "[a,b,c] = {b=>2,c=>3,a=>1}; $a == 1 and $b == 2 and $c == 3"      => :error,
       "$a = [1,2,3]; [x].collect |$x| { [a] += x; $a }"                  => :error,
       "$a = [a,x,c]; [x].collect |$x| { [a] -= x; $a }"                  => :error,
     }.each do |source, result|
         it "should parse and evaluate the expression '#{source}' to #{result}" do
           expect { parser.evaluate_string(scope, source, __FILE__)}.to raise_error(Puppet::ParseError)
         end
       end
   end
 
   context "When the evaluator evaluates conditionals" do
     {
       "if true {5}"                     => 5,
       "if false {5}"                    => nil,
       "if false {2} else {5}"           => 5,
       "if false {2} elsif true {5}"     => 5,
       "if false {2} elsif false {5}"    => nil,
       "unless false {5}"                => 5,
       "unless true {5}"                 => nil,
       "unless true {2} else {5}"        => 5,
       "$a = if true {5} $a"                     => 5,
       "$a = if false {5} $a"                    => nil,
       "$a = if false {2} else {5} $a"           => 5,
       "$a = if false {2} elsif true {5} $a"     => 5,
       "$a = if false {2} elsif false {5} $a"    => nil,
       "$a = unless false {5} $a"                => 5,
       "$a = unless true {5} $a"                 => nil,
       "$a = unless true {2} else {5} $a"        => 5,
     }.each do |source, result|
         it "should parse and evaluate the expression '#{source}' to #{result}" do
           parser.evaluate_string(scope, source, __FILE__).should == result
         end
       end
 
     {
       "case 1 { 1 : { yes } }"                               => 'yes',
       "case 2 { 1,2,3 : { yes} }"                            => 'yes',
       "case 2 { 1,3 : { no } 2: { yes} }"                    => 'yes',
       "case 2 { 1,3 : { no } 5: { no } default: { yes }}"    => 'yes',
       "case 2 { 1,3 : { no } 5: { no } }"                    => nil,
       "case 'banana' { 1,3 : { no } /.*ana.*/: { yes } }"    => 'yes',
       "case 'banana' { /.*(ana).*/: { $1 } }"                => 'ana',
       "case [1] { Array : { yes } }"                         => 'yes',
       "case [1] {
          Array[String] : { no }
          Array[Integer]: { yes }
       }"                                                     => 'yes',
       "case 1 {
          Integer : { yes }
          Type[Integer] : { no } }"                           => 'yes',
       "case Integer {
          Integer : { no }
          Type[Integer] : { yes } }"                          => 'yes',
 
     }.each do |source, result|
         it "should parse and evaluate the expression '#{source}' to #{result}" do
           parser.evaluate_string(scope, source, __FILE__).should == result
         end
       end
 
     {
       "2 ? { 1 => no, 2 => yes}"                          => 'yes',
       "3 ? { 1 => no, 2 => no}"                           => nil,
       "3 ? { 1 => no, 2 => no, default => yes }"          => 'yes',
       "3 ? { 1 => no, default => yes, 3 => no }"          => 'yes',
       "'banana' ? { /.*(ana).*/  => $1 }"                 => 'ana',
       "[2] ? { Array[String] => yes, Array => yes}"       => 'yes',
     }.each do |source, result|
         it "should parse and evaluate the expression '#{source}' to #{result}" do
           parser.evaluate_string(scope, source, __FILE__).should == result
         end
       end
   end
 
   context "When evaluator performs [] operations" do
     {
       "[1,2,3][0]"      => 1,
       "[1,2,3][2]"      => 3,
       "[1,2,3][3]"      => nil,
       "[1,2,3][-1]"     => 3,
       "[1,2,3][-2]"     => 2,
       "[1,2,3][-4]"     => nil,
       "[1,2,3,4][0,2]"  => [1,2],
       "[1,2,3,4][1,3]"  => [2,3,4],
       "[1,2,3,4][-2,2]"  => [3,4],
       "[1,2,3,4][-3,2]"  => [2,3],
       "[1,2,3,4][3,5]"   => [4],
       "[1,2,3,4][5,2]"   => [],
       "[1,2,3,4][0,-1]"  => [1,2,3,4],
       "[1,2,3,4][0,-2]"  => [1,2,3],
       "[1,2,3,4][0,-4]"  => [1],
       "[1,2,3,4][0,-5]"  => [],
       "[1,2,3,4][-5,2]"  => [1],
       "[1,2,3,4][-5,-3]" => [1,2],
       "[1,2,3,4][-6,-3]" => [1,2],
       "[1,2,3,4][2,-3]"  => [],
     }.each do |source, result|
       it "should parse and evaluate the expression '#{source}' to #{result}" do
         parser.evaluate_string(scope, source, __FILE__).should == result
       end
     end
 
     {
       "{a=>1, b=>2, c=>3}[a]"                => 1,
       "{a=>1, b=>2, c=>3}[c]"                => 3,
       "{a=>1, b=>2, c=>3}[x]"                => nil,
       "{a=>1, b=>2, c=>3}[c,b]"              => [3,2],
       "{a=>1, b=>2, c=>3}[a,b,c]"            => [1,2,3],
       "{a=>{b=>{c=>'it works'}}}[a][b][c]"   => 'it works',
       "$a = {undef => 10} $a[free_lunch]"     => nil,
       "$a = {undef => 10} $a[undef]"          => 10,
       "$a = {undef => 10} $a[$a[free_lunch]]" => 10,
       "$a = {} $a[free_lunch] == undef"       => true,
     }.each do |source, result|
       it "should parse and evaluate the expression '#{source}' to #{result}" do
         parser.evaluate_string(scope, source, __FILE__).should == result
       end
     end
 
     {
       "'abc'[0]"      => 'a',
       "'abc'[2]"      => 'c',
       "'abc'[-1]"     => 'c',
       "'abc'[-2]"     => 'b',
       "'abc'[-3]"     => 'a',
       "'abc'[-4]"     => '',
       "'abc'[3]"      => '',
       "abc[0]"        => 'a',
       "abc[2]"        => 'c',
       "abc[-1]"       => 'c',
       "abc[-2]"       => 'b',
       "abc[-3]"       => 'a',
       "abc[-4]"       => '',
       "abc[3]"        => '',
       "'abcd'[0,2]"   => 'ab',
       "'abcd'[1,3]"   => 'bcd',
       "'abcd'[-2,2]"  => 'cd',
       "'abcd'[-3,2]"  => 'bc',
       "'abcd'[3,5]"   => 'd',
       "'abcd'[5,2]"   => '',
       "'abcd'[0,-1]"  => 'abcd',
       "'abcd'[0,-2]"  => 'abc',
       "'abcd'[0,-4]"  => 'a',
       "'abcd'[0,-5]"  => '',
       "'abcd'[-5,2]"  => 'a',
       "'abcd'[-5,-3]" => 'ab',
       "'abcd'[-6,-3]" => 'ab',
       "'abcd'[2,-3]"  => '',
    }.each do |source, result|
       it "should parse and evaluate the expression '#{source}' to #{result}" do
         parser.evaluate_string(scope, source, __FILE__).should == result
       end
     end
 
     # Type operations (full set tested by tests covering type calculator)
     {
       "Array[Integer]"                  => types.array_of(types.integer),
       "Array[Integer,1]"                => types.constrain_size(types.array_of(types.integer),1, :default),
       "Array[Integer,1,2]"              => types.constrain_size(types.array_of(types.integer),1, 2),
       "Array[Integer,Integer[1,2]]"     => types.constrain_size(types.array_of(types.integer),1, 2),
       "Array[Integer,Integer[1]]"       => types.constrain_size(types.array_of(types.integer),1, :default),
       "Hash[Integer,Integer]"           => types.hash_of(types.integer, types.integer),
       "Hash[Integer,Integer,1]"         => types.constrain_size(types.hash_of(types.integer, types.integer),1, :default),
       "Hash[Integer,Integer,1,2]"       => types.constrain_size(types.hash_of(types.integer, types.integer),1, 2),
       "Hash[Integer,Integer,Integer[1,2]]" => types.constrain_size(types.hash_of(types.integer, types.integer),1, 2),
       "Hash[Integer,Integer,Integer[1]]"   => types.constrain_size(types.hash_of(types.integer, types.integer),1, :default),
       "Resource[File]"                  => types.resource('File'),
       "Resource['File']"                => types.resource(types.resource('File')),
       "File[foo]"                       => types.resource('file', 'foo'),
       "File[foo, bar]"                  => [types.resource('file', 'foo'), types.resource('file', 'bar')],
       "Pattern[a, /b/, Pattern[c], Regexp[d]]"  => types.pattern('a', 'b', 'c', 'd'),
       "String[1,2]"                     => types.constrain_size(types.string,1, 2),
       "String[Integer[1,2]]"            => types.constrain_size(types.string,1, 2),
       "String[Integer[1]]"              => types.constrain_size(types.string,1, :default),
     }.each do |source, result|
       it "should parse and evaluate the expression '#{source}' to #{result}" do
         parser.evaluate_string(scope, source, __FILE__).should == result
       end
     end
 
     # LHS where [] not supported, and missing key(s)
     {
       "Array[]"                    => :error,
       "'abc'[]"                    => :error,
       "Resource[]"                 => :error,
       "File[]"                     => :error,
       "String[]"                   => :error,
       "1[]"                        => :error,
       "3.14[]"                     => :error,
       "/.*/[]"                     => :error,
       "$a=[1] $a[]"                => :error,
     }.each do |source, result|
       it "should parse and evaluate the expression '#{source}' to #{result}" do
         expect { parser.evaluate_string(scope, source, __FILE__)}.to raise_error(/Syntax error/)
       end
     end
 
     # Errors when wrong number/type of keys are used
     {
       "Array[0]"                    => 'Array-Type[] arguments must be types. Got Fixnum',
       "Hash[0]"                     => 'Hash-Type[] arguments must be types. Got Fixnum',
       "Hash[Integer, 0]"            => 'Hash-Type[] arguments must be types. Got Fixnum',
       "Array[Integer,1,2,3]"        => 'Array-Type[] accepts 1 to 3 arguments. Got 4',
       "Array[Integer,String]"       => "A Type's size constraint arguments must be a single Integer type, or 1-2 integers (or default). Got a String-Type",
       "Hash[Integer,String, 1,2,3]" => 'Hash-Type[] accepts 1 to 4 arguments. Got 5',
       "'abc'[x]"                    => "The value 'x' cannot be converted to Numeric",
       "'abc'[1.0]"                  => "A String[] cannot use Float where Integer is expected",
       "'abc'[1,2,3]"                => "String supports [] with one or two arguments. Got 3",
       "Resource[0]"                 => 'First argument to Resource[] must be a resource type or a String. Got Fixnum',
       "Resource[a, 0]"              => 'Error creating type specialization of a Resource-Type, Cannot use Fixnum where String is expected',
       "File[0]"                     => 'Error creating type specialization of a File-Type, Cannot use Fixnum where String is expected',
       "String[a]"                   => "A Type's size constraint arguments must be a single Integer type, or 1-2 integers (or default). Got a String",
       "Pattern[0]"                  => 'Error creating type specialization of a Pattern-Type, Cannot use Fixnum where String or Regexp or Pattern-Type or Regexp-Type is expected',
       "Regexp[0]"                   => 'Error creating type specialization of a Regexp-Type, Cannot use Fixnum where String or Regexp is expected',
       "Regexp[a,b]"                 => 'A Regexp-Type[] accepts 1 argument. Got 2',
       "true[0]"                     => "Operator '[]' is not applicable to a Boolean",
       "1[0]"                        => "Operator '[]' is not applicable to an Integer",
       "3.14[0]"                     => "Operator '[]' is not applicable to a Float",
       "/.*/[0]"                     => "Operator '[]' is not applicable to a Regexp",
       "[1][a]"                      => "The value 'a' cannot be converted to Numeric",
       "[1][0.0]"                    => "An Array[] cannot use Float where Integer is expected",
       "[1]['0.0']"                  => "An Array[] cannot use Float where Integer is expected",
       "[1,2][1, 0.0]"               => "An Array[] cannot use Float where Integer is expected",
       "[1,2][1.0, -1]"              => "An Array[] cannot use Float where Integer is expected",
       "[1,2][1, -1.0]"              => "An Array[] cannot use Float where Integer is expected",
     }.each do |source, result|
       it "should parse and evaluate the expression '#{source}' to #{result}" do
         expect { parser.evaluate_string(scope, source, __FILE__)}.to raise_error(Regexp.new(Regexp.quote(result)))
       end
     end
 
     context "on catalog types" do
       it "[n] gets resource parameter [n]" do
         source = "notify { 'hello': message=>'yo'} Notify[hello][message]"
         parser.evaluate_string(scope, source, __FILE__).should == 'yo'
       end
 
       it "[n] gets class parameter [n]" do
         source = "class wonka($produces='chocolate'){ }
            include wonka
            Class[wonka][produces]"
 
         # This is more complicated since it needs to run like 3.x and do an import_ast
         adapted_parser = Puppet::Parser::E4ParserAdapter.new
         adapted_parser.file = __FILE__
         ast = adapted_parser.parse(source)
         scope.known_resource_types.import_ast(ast, '')
         ast.code.safeevaluate(scope).should == 'chocolate'
       end
 
       # Resource default and override expressions and resource parameter access with []
       {
         "notify { id: message=>explicit} Notify[id][message]"                   => "explicit",
         "Notify { message=>by_default} notify {foo:} Notify[foo][message]"      => "by_default",
         "notify {foo:} Notify[foo]{message =>by_override} Notify[foo][message]" => "by_override",
         "notify { foo: tag => evoe} Notify[foo][tag]"                           => "evoe",
         # Does not produce the defaults for tag
         "notify { foo: } Notify[foo][tag]"                                      => nil,
       }.each do |source, result|
         it "should parse and evaluate the expression '#{source}' to #{result}" do
           parser.evaluate_string(scope, source, __FILE__).should == result
         end
       end
 
       # Resource default and override expressions and resource parameter access error conditions
       {
         "notify { xid: message=>explicit} Notify[id][message]"  => /Resource not found/,
         "notify { id: message=>explicit} Notify[id][mustard]"   => /does not have a parameter called 'mustard'/,
         # NOTE: these meta-esque parameters are not recognized as such
         "notify { id: message=>explicit} Notify[id][title]"   => /does not have a parameter called 'title'/,
         "notify { id: message=>explicit} Notify[id]['type']"   => /does not have a parameter called 'type'/,
       }.each do |source, result|
         it "should parse '#{source}' and raise error matching #{result}" do
           expect { parser.evaluate_string(scope, source, __FILE__)}.to raise_error(result)
         end
       end
 
       context 'with errors' do
         { "Class['fail-whale']" => /Illegal name/,
           "Class[0]"            => /An Integer cannot be used where a String is expected/,
           "Class[/.*/]"         => /A Regexp cannot be used where a String is expected/,
           "Class[4.1415]"       => /A Float cannot be used where a String is expected/,
           "Class[Integer]"      => /An Integer-Type cannot be used where a String is expected/,
           "Class[File['tmp']]"   => /A File\['tmp'\] Resource-Reference cannot be used where a String is expected/,
         }.each do | source, error_pattern|
           it "an error is flagged for '#{source}'" do
             expect { parser.evaluate_string(scope, source, __FILE__)}.to raise_error(error_pattern)
           end
         end
       end
     end
   # end [] operations
   end
 
   context "When the evaluator performs boolean operations" do
     {
       "true and true"   => true,
       "false and true"  => false,
       "true and false"  => false,
       "false and false" => false,
       "true or true"    => true,
       "false or true"   => true,
       "true or false"   => true,
       "false or false"  => false,
       "! true"          => false,
       "!! true"         => true,
       "!! false"        => false,
       "! 'x'"           => false,
       "! ''"            => true,
       "! undef"         => true,
       "! [a]"           => false,
       "! []"            => false,
       "! {a=>1}"        => false,
       "! {}"            => false,
       "true and false and '0xwtf' + 1"  => false,
       "false or true  or '0xwtf' + 1"  => true,
     }.each do |source, result|
         it "should parse and evaluate the expression '#{source}' to #{result}" do
           parser.evaluate_string(scope, source, __FILE__).should == result
         end
       end
 
     {
       "false || false || '0xwtf' + 1"   => :error,
     }.each do |source, result|
         it "should parse and raise error for '#{source}'" do
           expect { parser.evaluate_string(scope, source, __FILE__) }.to raise_error(Puppet::ParseError)
         end
       end
   end
 
   context "When evaluator performs operations on literal undef" do
     it "computes non existing hash lookup as undef" do
       parser.evaluate_string(scope, "{a => 1}[b] == undef", __FILE__).should == true
       parser.evaluate_string(scope, "undef == {a => 1}[b]", __FILE__).should == true
     end
   end
 
   context "When evaluator performs calls" do
+    around(:each) do |example|
+      Puppet.override(:loaders => Puppet::Pops::Loaders.create_loaders()) do
+        example.run
+      end
+    end
+
     let(:populate) do
       parser.evaluate_string(scope, "$a = 10 $b = [1,2,3]")
     end
 
     {
       'sprintf( "x%iy", $a )'                 => "x10y",
       '"x%iy".sprintf( $a )'                  => "x10y",
       '$b.reduce |$memo,$x| { $memo + $x }'   => 6,
       'reduce($b) |$memo,$x| { $memo + $x }'  => 6,
     }.each do |source, result|
         it "should parse and evaluate the expression '#{source}' to #{result}" do
           populate
           parser.evaluate_string(scope, source, __FILE__).should == result
         end
       end
 
     {
       '"value is ${a*2} yo"'  => :error,
     }.each do |source, result|
         it "should parse and raise error for '#{source}'" do
           expect { parser.evaluate_string(scope, source, __FILE__) }.to raise_error(Puppet::ParseError)
         end
       end
 
     it "provides location information on error in unparenthesized call logic" do
     expect{parser.evaluate_string(scope, "include non_existing_class", __FILE__)}.to raise_error(Puppet::ParseError, /line 1\:1/)
     end
+
+    it 'defaults can be given in a lambda and used only when arg is missing' do
+      env_loader = Puppet.lookup(:loaders).public_environment_loader
+      fc = Puppet::Functions.create_function(:test) do
+        dispatch :test do
+          param 'Integer', 'count'
+          required_block_param
+        end
+        def test(count, block)
+          block.call({}, *[].fill(10, 0, count))
+        end
+      end
+      the_func = fc.new({}, env_loader)
+      env_loader.add_entry(:function, 'test', the_func, __FILE__)
+      expect(parser.evaluate_string(scope, "test(1) |$x, $y=20| { $x + $y}")).to eql(30)
+      expect(parser.evaluate_string(scope, "test(2) |$x, $y=20| { $x + $y}")).to eql(20)
+    end
+
+    it 'a given undef does not select the default value' do
+      env_loader = Puppet.lookup(:loaders).public_environment_loader
+      fc = Puppet::Functions.create_function(:test) do
+        dispatch :test do
+          param 'Optional[Object]', 'lambda_arg'
+          required_block_param
+        end
+        def test(lambda_arg, block)
+          block.call({}, lambda_arg)
+        end
+      end
+      the_func = fc.new({}, env_loader)
+      env_loader.add_entry(:function, 'test', the_func, __FILE__)
+      expect(parser.evaluate_string(scope, "test(undef) |$x=20| { $x == undef}")).to eql(true)
+    end
   end
 
   context "When evaluator performs string interpolation" do
     let(:populate) do
       parser.evaluate_string(scope, "$a = 10 $b = [1,2,3]")
     end
 
     {
       '"value is $a yo"'                      => "value is 10 yo",
       '"value is \$a yo"'                     => "value is $a yo",
       '"value is ${a} yo"'                    => "value is 10 yo",
       '"value is \${a} yo"'                   => "value is ${a} yo",
       '"value is ${$a} yo"'                   => "value is 10 yo",
       '"value is ${$a*2} yo"'                 => "value is 20 yo",
       '"value is ${sprintf("x%iy",$a)} yo"'   => "value is x10y yo",
       '"value is ${"x%iy".sprintf($a)} yo"'   => "value is x10y yo",
       '"value is ${[1,2,3]} yo"'              => "value is [1, 2, 3] yo",
       '"value is ${/.*/} yo"'                 => "value is /.*/ yo",
       '$x = undef "value is $x yo"'           => "value is  yo",
       '$x = default "value is $x yo"'         => "value is default yo",
       '$x = Array[Integer] "value is $x yo"'  => "value is Array[Integer] yo",
       '"value is ${Array[Integer]} yo"'       => "value is Array[Integer] yo",
     }.each do |source, result|
         it "should parse and evaluate the expression '#{source}' to #{result}" do
           populate
           parser.evaluate_string(scope, source, __FILE__).should == result
         end
       end
 
     it "should parse and evaluate an interpolation of a hash" do
       source = '"value is ${{a=>1,b=>2}} yo"'
       # This test requires testing against two options because a hash to string
       # produces a result that is unordered
       hashstr = {'a' => 1, 'b' => 2}.to_s
       alt_results = ["value is {a => 1, b => 2} yo", "value is {b => 2, a => 1} yo" ]
       populate
       parse_result = parser.evaluate_string(scope, source, __FILE__)
       alt_results.include?(parse_result).should == true
     end
 
     {
       '"value is ${a*2} yo"'  => :error,
     }.each do |source, result|
         it "should parse and raise error for '#{source}'" do
           expect { parser.evaluate_string(scope, source, __FILE__) }.to raise_error(Puppet::ParseError)
         end
       end
   end
 
   context "When evaluating variables" do
     context "that are non existing an error is raised for" do
       it "unqualified variable" do
         expect { parser.evaluate_string(scope, "$quantum_gravity", __FILE__) }.to raise_error(/Unknown variable/)
       end
 
       it "qualified variable" do
         expect { parser.evaluate_string(scope, "$quantum_gravity::graviton", __FILE__) }.to raise_error(/Unknown variable/)
       end
     end
 
     it "a lex error should be raised for '$foo::::bar'" do
       expect { parser.evaluate_string(scope, "$foo::::bar") }.to raise_error(Puppet::LexError, /Illegal fully qualified name at line 1:7/)
     end
 
     { '$a = $0'   => nil,
       '$a = $1'   => nil,
     }.each do |source, value|
       it "it is ok to reference numeric unassigned variables '#{source}'" do
         parser.evaluate_string(scope, source, __FILE__).should == value
       end
     end
 
     { '$00 = 0'   => /must be a decimal value/,
       '$0xf = 0'  => /must be a decimal value/,
       '$0777 = 0' => /must be a decimal value/,
       '$123a = 0' => /must be a decimal value/,
     }.each do |source, error_pattern|
       it "should raise an error for '#{source}'" do
         expect { parser.evaluate_string(scope, source, __FILE__) }.to raise_error(error_pattern)
       end
     end
 
     context "an initial underscore in the last segment of a var name is allowed" do
       { '$_a  = 1'   => 1,
         '$__a = 1'   => 1,
       }.each do |source, value|
         it "as in this example '#{source}'" do
           parser.evaluate_string(scope, source, __FILE__).should == value
         end
       end
     end
   end
 
   context "When evaluating relationships" do
     it 'should form a relation with File[a] -> File[b]' do
       source = "File[a] -> File[b]"
       parser.evaluate_string(scope, source, __FILE__)
       scope.compiler.should have_relationship(['File', 'a', '->', 'File', 'b'])
     end
 
     it 'should form a relation with resource -> resource' do
       source = "notify{a:} -> notify{b:}"
       parser.evaluate_string(scope, source, __FILE__)
       scope.compiler.should have_relationship(['Notify', 'a', '->', 'Notify', 'b'])
     end
 
     it 'should form a relation with [File[a], File[b]] -> [File[x], File[y]]' do
       source = "[File[a], File[b]] -> [File[x], File[y]]"
       parser.evaluate_string(scope, source, __FILE__)
       scope.compiler.should have_relationship(['File', 'a', '->', 'File', 'x'])
       scope.compiler.should have_relationship(['File', 'b', '->', 'File', 'x'])
       scope.compiler.should have_relationship(['File', 'a', '->', 'File', 'y'])
       scope.compiler.should have_relationship(['File', 'b', '->', 'File', 'y'])
     end
 
     it 'should tolerate (eliminate) duplicates in operands' do
       source = "[File[a], File[a]] -> File[x]"
       parser.evaluate_string(scope, source, __FILE__)
       scope.compiler.should have_relationship(['File', 'a', '->', 'File', 'x'])
       scope.compiler.relationships.size.should == 1
     end
 
     it 'should form a relation with <-' do
       source = "File[a] <- File[b]"
       parser.evaluate_string(scope, source, __FILE__)
       scope.compiler.should have_relationship(['File', 'b', '->', 'File', 'a'])
     end
 
     it 'should form a relation with <-' do
       source = "File[a] <~ File[b]"
       parser.evaluate_string(scope, source, __FILE__)
       scope.compiler.should have_relationship(['File', 'b', '~>', 'File', 'a'])
     end
   end
 
   context "When evaluating heredoc" do
     it "evaluates plain heredoc" do
       src = "@(END)\nThis is\nheredoc text\nEND\n"
       parser.evaluate_string(scope, src).should == "This is\nheredoc text\n"
     end
 
     it "parses heredoc with margin" do
       src = [
       "@(END)",
       "   This is",
       "   heredoc text",
       "   | END",
       ""
       ].join("\n")
       parser.evaluate_string(scope, src).should == "This is\nheredoc text\n"
     end
 
     it "parses heredoc with margin and right newline trim" do
       src = [
       "@(END)",
       "   This is",
       "   heredoc text",
       "   |- END",
       ""
       ].join("\n")
       parser.evaluate_string(scope, src).should == "This is\nheredoc text"
     end
 
     it "parses escape specification" do
       src = <<-CODE
       @(END/t)
       Tex\\tt\\n
       |- END
       CODE
       parser.evaluate_string(scope, src).should == "Tex\tt\\n"
     end
 
     it "parses syntax checked specification" do
       src = <<-CODE
       @(END:json)
       ["foo", "bar"]
       |- END
       CODE
       parser.evaluate_string(scope, src).should == '["foo", "bar"]'
     end
 
     it "parses syntax checked specification with error and reports it" do
       src = <<-CODE
       @(END:json)
       ['foo', "bar"]
       |- END
       CODE
       expect { parser.evaluate_string(scope, src)}.to raise_error(/Cannot parse invalid JSON string/)
     end
 
     it "parses interpolated heredoc epression" do
       src = <<-CODE
       $name = 'Fjodor'
       @("END")
       Hello $name
       |- END
       CODE
       parser.evaluate_string(scope, src).should == "Hello Fjodor"
     end
 
   end
 
   context "Detailed Error messages are reported" do
     it 'for illegal type references' do
       source = '1+1 { "title": }'
       # Error references position 5 at the opening '{'
       # Set file to nil to make it easier to match with line number (no file name in output)
       expect { parser.parse_string(source, nil) }.to raise_error(/Expression is not valid as a resource.*line 1:5/)
     end
 
     it 'for non r-value producing <| |>' do
       expect { parser.parse_string("$a = File <| |>", nil) }.to raise_error(/A Virtual Query does not produce a value at line 1:6/)
     end
 
     it 'for non r-value producing <<| |>>' do
       expect { parser.parse_string("$a = File <<| |>>", nil) }.to raise_error(/An Exported Query does not produce a value at line 1:6/)
     end
 
     it 'for non r-value producing define' do
       Puppet.expects(:err).with("Invalid use of expression. A 'define' expression does not produce a value at line 1:6")
       Puppet.expects(:err).with("Classes, definitions, and nodes may only appear at toplevel or inside other classes at line 1:6")
       expect { parser.parse_string("$a = define foo { }", nil) }.to raise_error(/2 errors/)
     end
 
     it 'for non r-value producing class' do
       Puppet.expects(:err).with("Invalid use of expression. A Host Class Definition does not produce a value at line 1:6")
       Puppet.expects(:err).with("Classes, definitions, and nodes may only appear at toplevel or inside other classes at line 1:6")
       expect { parser.parse_string("$a = class foo { }", nil) }.to raise_error(/2 errors/)
     end
 
     it 'for unclosed quote with indication of start position of string' do
       source = <<-SOURCE.gsub(/^ {6}/,'')
       $a = "xx
       yyy
       SOURCE
       # first char after opening " reported as being in error.
       expect { parser.parse_string(source) }.to raise_error(/Unclosed quote after '"' followed by 'xx\\nyy\.\.\.' at line 1:7/)
     end
 
     it 'for multiple errors with a summary exception' do
       Puppet.expects(:err).with("Invalid use of expression. A Node Definition does not produce a value at line 1:6")
       Puppet.expects(:err).with("Classes, definitions, and nodes may only appear at toplevel or inside other classes at line 1:6")
       expect { parser.parse_string("$a = node x { }",nil) }.to raise_error(/2 errors/)
     end
 
     it 'for a bad hostname' do
       expect {
         parser.parse_string("node 'macbook+owned+by+name' { }", nil)
       }.to raise_error(/The hostname 'macbook\+owned\+by\+name' contains illegal characters.*at line 1:6/)
     end
 
     it 'for a hostname with interpolation' do
       source = <<-SOURCE.gsub(/^ {6}/,'')
       $name = 'fred'
       node "macbook-owned-by$name" { }
       SOURCE
       expect {
         parser.parse_string(source, nil)
       }.to raise_error(/An interpolated expression is not allowed in a hostname of a node at line 2:23/)
     end
 
   end
 
   matcher :have_relationship do |expected|
     calc = Puppet::Pops::Types::TypeCalculator.new
 
     match do |compiler|
       op_name = {'->' => :relationship, '~>' => :subscription}
       compiler.relationships.any? do | relation |
         relation.source.type == expected[0] &&
         relation.source.title == expected[1] &&
         relation.type == op_name[expected[2]] &&
         relation.target.type == expected[3] &&
         relation.target.title == expected[4]
       end
     end
 
     failure_message_for_should do |actual|
       "Relationship #{expected[0]}[#{expected[1]}] #{expected[2]} #{expected[3]}[#{expected[4]}] but was unknown to compiler"
     end
   end
 
 end