Class: Alda::Event

Inherits:
Object
  • Object
show all
Defined in:
lib/alda-rb/event.rb

Overview

The class of elements of Alda::EventList#events.

Instance Attribute Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#container ⇒ Object

The Alda::EventContainer object that contains it. It may be nil if there is not a container containing it, especially probably when it itself is an Alda::EventContainer.



16
17
18
 
# File 'lib/alda-rb/event.rb', line 16

def container
  @container
end

#parent ⇒ Object

The Alda::EventList object that contains it.

Note that it may not be directly contained, but with an Alda::EventContainer object in the middle.



10
11
12
 
# File 'lib/alda-rb/event.rb', line 10

def parent
  @parent
end

Instance Method Details

#==(other) ⇒ Object

:call-seq:

event == other -> true or false

Whether it is equal to other. To be overriden.

Note that #parent and #container should not be taken into account when comparing two events.



94
95
96
 
# File 'lib/alda-rb/event.rb', line 94

def == other
	super
end

#detach_from_parent(except = []) ⇒ Object

Delete itself (or its topmost container if it has) from its #parent. If it is not at its #parent’s end, raises Alda::OrderError.

Here is a list of cases where the method is invoked:

  1. Using the sequence sugar when operating an Alda::EventList.

  2. Using Alda::EventContainer#/ to create chords or parts of multiple instruments.

  3. Using dot accessor of Alda::Part. See Alda::Part#method_missing.

  4. Using the inline lisp sugar. See Alda::InlineLisp.

This method needs invoking in these cases because if an event is created using Alda::EventList sugars (see Alda::EventList#method_missing), it is automatically pushed to its #parent. However, the cases above requires the event be contained in another object.

The parameter except specifies an Array of classes. If #parent is an instance of any of the classes in except, the method does nothing.



67
68
69
70
71
72
73
 
# File 'lib/alda-rb/event.rb', line 67

def detach_from_parent except = []
	event = self
	event = event.container while event.container
	if @parent && except.none? { @parent.is_a? _1 } && event != (got = @parent.events.pop)
		raise Alda::OrderError.new event, got
	end
end

#is_event_of?(klass) ⇒ Boolean

:call-seq:

is_event_of?(klass) -> true or false

Whether it is an event of the given class (klass). By default, this is the same as is_a?(klass). It is overridden in Alda::EventContainer.

Returns:

  • (Boolean) 


82
83
84
 
# File 'lib/alda-rb/event.rb', line 82

def is_event_of? klass
	is_a? klass
end

#on_contained ⇒ Object

The callback invoked when it is contained in an Alda::EventContainer. It is overridden in Alda::InlineLisp and Alda::EventList. It is called in Alda::EventContainer#on_containing.

class Alda::Note
  def on_contained
    super
    puts 'a note contained'
  end
end
Alda::Score.new { c } # => outputs "a note contained"



30
31
 
# File 'lib/alda-rb/event.rb', line 30

def on_contained
end

#to_alda_code ⇒ Object

:call-seq:

to_alda_code() -> String

Converts to alda code. To be overridden in subclasses.



38
39
40
 
# File 'lib/alda-rb/event.rb', line 38

def to_alda_code
	''
end