Class: Mullet::DefaultScope

Inherits:
Object
  • Object
show all
Includes:
Scope
Defined in:
lib/mullet/default_scope.rb

Overview

Default scope implementation which resolves variable names to values by reading from a data object. Given a variable name key, the following mechanisms are tried in this order:

* If the variable name is `.`, then return the object.
* If the object has a method named _key_ taking no parameters, then use
  the value returned from calling the method.
* If the object has an instance variable named @_key_, then use the
  variable value.
* If the object is a `Hash`, then use _key_ as the key to retrieve the
  value from the hash.

If the value is a Proc, then use the value returned from calling it.

Constant Summary

Constants included from Scope

Scope::NOT_FOUND

Instance Method Summary collapse

Constructor Details

#initialize(data) ⇒ DefaultScope

Returns a new instance of DefaultScope.



21
22
23
 
# File 'lib/mullet/default_scope.rb', line 21

def initialize(data)
  @data = data
end

Instance Method Details

#fetch_impl(name) ⇒ Object 



25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
 
# File 'lib/mullet/default_scope.rb', line 25

def fetch_impl(name)
  if name == :'.'
    return @data
  end

  # Does the variable name match a method name in the object?
  if @data.respond_to?(name)
    method = @data.method(name)
    if method.arity == 0
      return method.call()
    end
  end

  # Does the variable name match an instance variable name in the object?
  variable = :"@#{name}"
  if @data.instance_variable_defined?(variable)
    return @data.instance_variable_get(variable)
  end

  # Is the variable name a key in a Hash?
  if @data.respond_to?(:fetch)
    # If the key was not found, then try to find it as a String.
    return @data.fetch(name) {|k| @data.fetch(k.to_s(), NOT_FOUND) }
  end

  return NOT_FOUND
end

#get_variable_value(name) ⇒ Object

Resolves variable name to value.

Parameters:

  • name (Symbol) —

    variable name

Returns:

  • variable value



58
59
60
61
62
63
64
 
# File 'lib/mullet/default_scope.rb', line 58

def get_variable_value(name)
  value = fetch_impl(name)
  if value.is_a?(Proc)
    value = value.call()
  end
  return value
end