Class: Dagger::Default

Inherits:
Object
  • Object
show all
Defined in:
lib/dagger/default.rb

Overview

Default value generator for a dictionary

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(vertex, cached: false, fallback: nil, rule_prefix: '_default') ⇒ Default

Initialize a default value generator for a vertex

:call-seq:

new(graph, vertex) => Dagger::Default
new(*, cached: false)
new(*, rule_prefix: '_default')



23
24
25
26
27
28
29
30
31
32
33
 
# File 'lib/dagger/default.rb', line 23

def initialize(vertex,
               cached: false,
               fallback: nil,
               rule_prefix: '_default')
  @vertex = vertex
  @cached = cached
  @fallback = fallback
  @rule_prefix = rule_prefix.to_key_path
  @default_proc = ->(tree, key) { generate(tree, key) }
  @locks = Set[]
end

Instance Attribute Details

#cached=(value) ⇒ Object (writeonly)

Sets the attribute cached

Parameters:

  • value —

    the value to set the attribute cached to.



44
45
46
 
# File 'lib/dagger/default.rb', line 44

def cached=(value)
  @cached = value
end

#default_proc ⇒ Object (readonly)

Returns the value of attribute default_proc.



35
36
37
 
# File 'lib/dagger/default.rb', line 35

def default_proc
  @default_proc
end

Class Method Details

.proc(*args) ⇒ Object 



13
14
15
 
# File 'lib/dagger/default.rb', line 13

def self.proc(*args)
  new(*args).default_proc
end

Instance Method Details

#cached? ⇒ Boolean

Verify state of caching of future values

:call-seq:

cached? => bool

Returns:

  • (Boolean) 


41
42
43
 
# File 'lib/dagger/default.rb', line 41

def cached?
  !(!@cached)
end

#generate(tree, key) ⇒ Object

Generate a default value for a key, possibly caching the result in the tree.

:call-seq:

generate(tree, key) => value || KeyError

Raises a KeyError if the default value cannot be generated. Raises a RuntimeError in case of a deadlock for key.



54
55
56
57
 
# File 'lib/dagger/default.rb', line 54

def generate(tree, key)
  key = key.to_key_path
  with_locked_key(key) { |locked_key| cached_value(tree, locked_key) }
end