Class: Puppet::Pops::Loader::PuppetFunctionInstantiator

Inherits:
Object
  • Object
show all
Defined in:
lib/puppet/pops/loader/puppet_function_instantiator.rb

Overview

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

Class Method Summary collapse

Class Method Details

.create(loader, typed_name, source_ref, pp_code_string) ⇒ Functions::Function

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.

Parameters:

  • loader (Loader)

    The loader the function is associated with

  • typed_name (TypedName)

    the type / name of the function to load

  • source_ref (URI, String)

    a reference to the source / origin of the puppet code to evaluate

  • pp_code_string (String)

    puppet code in a string

Returns:

  • (Functions::Function)
    • an instantiated function with global scope closure associated with the given loader


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# File 'lib/puppet/pops/loader/puppet_function_instantiator.rb', line 17

def self.create(loader, typed_name, source_ref, pp_code_string)
  parser = Parser::EvaluatingParser.new()

  # parse and validate
  result = parser.parse_string(pp_code_string, source_ref)
  # Only one function is allowed (and no other definitions)
  case result.definitions.size
  when 0
    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 }
  when 1
    # ok
  else
    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 }
  end
  the_function_definition = result.definitions[0]

  unless the_function_definition.is_a?(Model::FunctionDefinition)
    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 }
  end
  unless the_function_definition.name == typed_name.name
    expected = typed_name.name
    actual = the_function_definition.name
    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 }
  end
  unless result.body == the_function_definition
    raise ArgumentError, _("The code loaded from %{source} contains additional logic - can only contain the function %{name}") % { source: source_ref, name: typed_name.name }
  end

  # Adapt the function definition with loader - this is used from logic contained in it body to find the
  # loader to use when making calls to the new function API. Such logic have a hard time finding the closure (where
  # the loader is known - hence this mechanism
  private_loader = loader.private_loader
  Adapters::LoaderAdapter.adapt(the_function_definition).loader_name = private_loader.loader_name

  # Cannot bind loaded functions to global scope, that must be done without binding that scope as
  # loaders survive a compilation.
  closure_scope = nil # Puppet.lookup(:global_scope) { {} }

  created = create_function_class(the_function_definition)
  # create the function instance - it needs closure (scope), and loader (i.e. where it should start searching for things
  # when calling functions etc.
  # It should be bound to global scope

  created.new(closure_scope, private_loader)
end

.create_from_model(function_definition, loader) ⇒ Array<TypedName, Functions.Function>

Creates Function class and instantiates it based on a FunctionDefinition model

Returns:

  • (Array<TypedName, Functions.Function>)
    • array of

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


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# File 'lib/puppet/pops/loader/puppet_function_instantiator.rb', line 67

def self.create_from_model(function_definition, loader)
  created = create_function_class(function_definition)
  typed_name = TypedName.new(:function, function_definition.name)
  [typed_name, created.new(nil, loader)]
end

.create_function_class(function_definition) ⇒ Object


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# File 'lib/puppet/pops/loader/puppet_function_instantiator.rb', line 73

def self.create_function_class(function_definition)
  # Create a 4x function wrapper around a named closure
  Puppet::Functions.create_function(function_definition.name, Puppet::Functions::PuppetFunction) do
    # TODO: should not create a new evaluator per function
    init_dispatch(Evaluator::Closure::Named.new(
      function_definition.name,
      Evaluator::EvaluatorImpl.new(), function_definition))
  end
end