class Puppet::Pops::Loader::PuppetFunctionInstantiator

The PuppetFunctionInstantiator instantiates a Puppet::Functions::PuppetFunction given a Puppet Programming language source that when called evaluates the Puppet logic it contains.

Public Class Methods

create(loader, typed_name, source_ref, pp_code_string) click to toggle source

Produces an instance of the Function class with the given typed_name, or fails with an error if the given puppet source does not produce this instance when evaluated.

@param loader [Loader] The loader the function is associated with @param typed_name [TypedName] the type / name of the function to load @param source_ref [URI, String] a reference to the source / origin of the puppet code to evaluate @param pp_code_string [String] puppet code in a string

@return [Functions::Function] - an instantiated function with global scope closure associated with the given loader

   # File lib/puppet/pops/loader/puppet_function_instantiator.rb
18 def self.create(loader, typed_name, source_ref, pp_code_string)
19   parser = Parser::EvaluatingParser.new()
20 
21   # parse and validate
22   result = parser.parse_string(pp_code_string, source_ref)
23   # Only one function is allowed (and no other definitions)
24   case result.definitions.size
25   when 0
26     raise ArgumentError, _("The code loaded from %{source_ref} does not define the function '%{func_name}' - it is empty.") % { source_ref: source_ref, func_name: typed_name.name }
27   when 1
28     # ok
29   else
30     raise ArgumentError, _("The code loaded from %{source_ref} must contain only the function '%{type_name}' - it has additional definitions.") % { source_ref: source_ref, type_name: typed_name.name }
31   end
32   the_function_definition = result.definitions[0]
33 
34   unless the_function_definition.is_a?(Model::FunctionDefinition)
35     raise ArgumentError, _("The code loaded from %{source_ref} does not define the function '%{type_name}' - no function found.") % { source_ref: source_ref, type_name: typed_name.name }
36   end
37   unless the_function_definition.name == typed_name.name
38     expected = typed_name.name
39     actual = the_function_definition.name
40     raise ArgumentError, _("The code loaded from %{source_ref} produced function with the wrong name, expected %{expected}, actual %{actual}") % { source_ref: source_ref, expected: expected, actual: actual }
41   end
42   unless result.body == the_function_definition
43     raise ArgumentError, _("The code loaded from %{source} contains additional logic - can only contain the function %{name}") % { source: source_ref, name: typed_name.name }
44   end
45 
46   # Adapt the function definition with loader - this is used from logic contained in it body to find the
47   # loader to use when making calls to the new function API. Such logic have a hard time finding the closure (where
48   # the loader is known - hence this mechanism
49   private_loader = loader.private_loader
50   Adapters::LoaderAdapter.adapt(the_function_definition).loader_name = private_loader.loader_name
51 
52   # Cannot bind loaded functions to global scope, that must be done without binding that scope as
53   # loaders survive a compilation.
54   closure_scope = nil # Puppet.lookup(:global_scope) { {} }
55 
56   created = create_function_class(the_function_definition)
57   # create the function instance - it needs closure (scope), and loader (i.e. where it should start searching for things
58   # when calling functions etc.
59   # It should be bound to global scope
60 
61   created.new(closure_scope, private_loader)
62 end

create_from_model(function_definition, loader) click to toggle source

Creates Function class and instantiates it based on a FunctionDefinition model @return [Array<TypedName, Functions.Function>] - array of

typed name, and an instantiated function with global scope closure associated with the given loader

   # File lib/puppet/pops/loader/puppet_function_instantiator.rb
68 def self.create_from_model(function_definition, loader)
69   created = create_function_class(function_definition)
70   typed_name = TypedName.new(:function, function_definition.name)
71   [typed_name, created.new(nil, loader)]
72 end

create_function_class(function_definition) click to toggle source

   # File lib/puppet/pops/loader/puppet_function_instantiator.rb
74 def self.create_function_class(function_definition)
75   # Create a 4x function wrapper around a named closure
76   Puppet::Functions.create_function(function_definition.name, Puppet::Functions::PuppetFunction) do
77     # TODO: should not create a new evaluator per function
78     init_dispatch(Evaluator::Closure::Named.new(
79       function_definition.name,
80       Evaluator::EvaluatorImpl.new(), function_definition))
81   end
82 end