Module: Docile::Execution Private

Included in:
Docile
Defined in:
lib/docile/execution.rb

Overview

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

A namespace for functions relating to the execution of a block against a proxy object.

Class Method Summary collapse

Class Method Details

.exec_in_proxy_context(dsl, proxy_type, *args, &block) ⇒ Object

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

Execute a block in the context of an object whose methods represent the commands in a DSL, using a specific proxy class.

Parameters:

  • dsl (Object) —

    context object whose methods make up the (initial) DSL

  • proxy_type (FallbackContextProxy, ChainingFallbackContextProxy) —

    which class to instantiate as proxy context

  • args (Array) —

    arguments to be passed to the block

  • block (Proc) —

    the block of DSL commands to be executed

Returns:

  • (Object) —

    the return value of the block



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# File 'lib/docile/execution.rb', line 19

def exec_in_proxy_context(dsl, proxy_type, *args, &block)
  block_context = eval("self", block.binding) # rubocop:disable Style/EvalWithLocation

  # Use #equal? to test strict object identity (assuming that this dictum
  # from the Ruby docs holds: "[u]nlike ==, the equal? method should never
  # be overridden by subclasses as it is used to determine object
  # identity")
  return dsl.instance_exec(*args, &block) if dsl.equal?(block_context)

  proxy_context = proxy_type.new(dsl, block_context)
  begin
    block_context.instance_variables.each do |ivar|
      value_from_block = block_context.instance_variable_get(ivar)
      proxy_context.instance_variable_set(ivar, value_from_block)
    end

    proxy_context.instance_exec(*args, &block)
  ensure
    if block_context.respond_to?(:__docile_undo_fallback__)
      block_context.send(:__docile_undo_fallback__)
    end

    block_context.instance_variables.each do |ivar|
      next unless proxy_context.instance_variables.include?(ivar)

      value_from_dsl_proxy = proxy_context.instance_variable_get(ivar)
      block_context.instance_variable_set(ivar, value_from_dsl_proxy)
    end
  end
end