Class: Fable::CallStack

Inherits:
Object
  • Object
show all
Defined in:
lib/fable/call_stack.rb

Defined Under Namespace

Classes: Element, Thread

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(story_context_or_call_stack) ⇒ CallStack

Returns a new instance of CallStack.



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# File 'lib/fable/call_stack.rb', line 5

def initialize(story_context_or_call_stack)
  if story_context_or_call_stack.is_a?(Story)
    start_of_root = Pointer.start_of(story_context_or_call_stack.root_content_container)
    reset!
  elsif story_context_or_call_stack.is_a?(CallStack)
    call_stack_to_copy = story_context_or_call_stack
    self.threads = []

    call_stack_to_copy.threads.each do |thread|
      self.threads << thread.copy
    end

    self.thread_container = call_stack_to_copy.thread_counter
    self.start_of_root = call_stack_to_copy.start_of_root
  end
end

Instance Attribute Details

#start_of_root ⇒ Object

Returns the value of attribute start_of_root.



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# File 'lib/fable/call_stack.rb', line 3

def start_of_root
  @start_of_root
end

#thread_counter ⇒ Object

Returns the value of attribute thread_counter.



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# File 'lib/fable/call_stack.rb', line 3

def thread_counter
  @thread_counter
end

#threads ⇒ Object

Returns the value of attribute threads.



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# File 'lib/fable/call_stack.rb', line 3

def threads
  @threads
end

Instance Method Details

#call_stack ⇒ Object 



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# File 'lib/fable/call_stack.rb', line 141

def call_stack
  current_thread.call_stack
end

#call_stack_trace ⇒ Object 



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# File 'lib/fable/call_stack.rb', line 190

def call_stack_trace
  result = StringIO.new

  self.threads.each_with_index do |thread, i|
    is_current_thread = thread == current_thread

    result << "=== THREAD #{i}/#{threads.count} #{'(current)' if is_current_thread }\n"

    thread.call_stack.each do |element|
      case element.type
      when :function
        result << "  [FUNCTION] "
      when :tunnel
        result << "  [TUNNEL] "
      end

      pointer = element.current_pointer
      if !pointer.null_pointer?
        result << "<SOMEWHERE IN #{pointer.container.path.to_s}>\n"
      end
    end
  end

  result.rewind
  result.read
end

#can_pop?(type = nil) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/fable/call_stack.rb', line 79

def can_pop?(type = nil)
  return false if call_stack.size <= 1
  return true if type.nil?
  return current_element.type == type
end

#can_pop_thread? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/fable/call_stack.rb', line 59

def can_pop_thread?
  threads.size > 1 && !element_is_evaluate_from_game?
end

#context_for_variable_named(name) ⇒ Object

Find the most appropriate context for this variable. Are we referencing a temporary or global variable? Note that the compiler will have warned us about possible conflicts, so anything that happens here should be safe



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# File 'lib/fable/call_stack.rb', line 126

def context_for_variable_named(name)
  # Current temporary context?
  # (Shouldn't attempt to access contexts higher in the callstack)
  if current_element.temporary_variables.has_key?(name)
    return current_element_index + 1
  else
    # Global
    return 0
  end
end

#current_element ⇒ Object 



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# File 'lib/fable/call_stack.rb', line 37

def current_element
  thread = threads.last
  thread.call_stack.last
end

#current_element_index ⇒ Object 



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# File 'lib/fable/call_stack.rb', line 42

def current_element_index
  call_stack.size - 1
end

#current_thread ⇒ Object 



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# File 'lib/fable/call_stack.rb', line 46

def current_thread
  threads.last
end

#current_thread=(value) ⇒ Object 



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# File 'lib/fable/call_stack.rb', line 50

def current_thread=(value)
  if threads.size != 1
    raise StoryError, "Shouldn't be directly setting the current thread when we have a stack of them"
  end

  threads.clear
  threads << value
end

#depth ⇒ Object 



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# File 'lib/fable/call_stack.rb', line 33

def depth
  elements.size
end

#element_is_evaluate_from_game? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/fable/call_stack.rb', line 63

def element_is_evaluate_from_game?
  current_element.type == PushPopType::TYPES[:function_evaluation_from_game]
end

#elements ⇒ Object 



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# File 'lib/fable/call_stack.rb', line 29

def elements
  call_stack
end

#fork_thread! ⇒ Object 



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# File 'lib/fable/call_stack.rb', line 151

def fork_thread!
  forked_thread = current_thread.copy
  self.thread_counter += 1
  forked_thread.thread_index = self.thread_counter

  return forked_thread
end

#from_hash!(hash_to_use, story_context) ⇒ Object 



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# File 'lib/fable/call_stack.rb', line 167

def from_hash!(hash_to_use, story_context)
  self.threads = []

  hash_to_use["threads"].each do |thread_object|
    self.threads << Thread.new(thread_object, story_context)
  end

  self.thread_counter = hash_to_use["threadCounter"]
  self.start_of_root = Pointer.start_of(story_context.root_content_container)
  self
end

#get_temporary_variable_with_name(name, context_index = -1)) ⇒ Object

Get variable value, dereferencing a variable pointer if necessary



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# File 'lib/fable/call_stack.rb', line 94

def get_temporary_variable_with_name(name, context_index = -1)
  if context_index == -1
    context_index = current_element_index + 1
  end

  context_element = call_stack[context_index - 1]

  return context_element.temporary_variables[name]
end

#pop!(type = nil) ⇒ Object 



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# File 'lib/fable/call_stack.rb', line 85

def pop!(type=nil)
  if can_pop?(type)
    call_stack.pop
  else
    raise Error, "Mismatched push/pop in Callstack"
  end
end

#pop_thread! ⇒ Object 



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# File 'lib/fable/call_stack.rb', line 159

def pop_thread!
  if can_pop_thread?
    threads.delete(current_thread)
  else
    raise Error, "Can't pop thread"
  end
end

#push(type, options = {external_evaluation_stack_height: 0, output_stream_length_when_pushed: 0}) ⇒ Object 



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# File 'lib/fable/call_stack.rb', line 67

def push(type, options = {external_evaluation_stack_height: 0, output_stream_length_when_pushed: 0})
  external_evaluation_stack_height = options[:external_evaluation_stack_height] || 0
  output_stream_length_when_pushed = options[:output_stream_length_when_pushed] || 0
  # When pushing to callstack, maintain the current content path, but jump
  # out of expressions by default
  element = Element.new(type, current_element.current_pointer, in_expression_evaluation: false)
  element.evaluation_stack_height_when_pushed = external_evaluation_stack_height
  element.function_start_in_output_stream = output_stream_length_when_pushed

  self.call_stack << element
end

#push_thread! ⇒ Object 



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# File 'lib/fable/call_stack.rb', line 145

def push_thread!
  new_thread = current_thread.copy
  self.thread_counter += 1
  self.threads << new_thread
end

#reset! ⇒ Object 



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# File 'lib/fable/call_stack.rb', line 22

def reset!
  new_thread = Thread.new
  new_thread.call_stack << Element.new(:tunnel, self.start_of_root)
  self.threads = [new_thread]
  self.thread_counter = 0
end

#set_temporary_variable(name, value, declare_new, context_index = -1)) ⇒ Object 



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# File 'lib/fable/call_stack.rb', line 104

def set_temporary_variable(name, value, declare_new, context_index = -1)
  if context_index == -1
    context_index = current_element_index + 1
  end

  context_element = call_stack[context_index - 1]

  if !declare_new && !context_element.temporary_variables.has_key?(name)
    raise Error, "Could not find temporary variable to set: #{name}"
  end

  if context_element.temporary_variables.has_key?(name)
    old_value = context_element.temporary_variables[name]
    ListValue.retain_list_origins_for_assignment(old_value, value)
  end

  context_element.temporary_variables[name] = value
end

#thread_with_index(index) ⇒ Object 



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# File 'lib/fable/call_stack.rb', line 137

def thread_with_index(index)
  threads.find{|thread| thread.thread_index == index}
end

#to_hash ⇒ Object 



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# File 'lib/fable/call_stack.rb', line 179

def to_hash
  export = {}
  export["threads"] = []
  self.threads.each do |thread|
    export["threads"] << thread.to_hash
  end

  export["threadCounter"] = self.thread_counter
  export
end