Class: Liquid::VariableLookup

Inherits:
Object
  • Object
show all
Defined in:
lib/liquid/variable_lookup.rb

Constant Summary collapse

SQUARE_BRACKETED =
/\A\[(.*)\]\z/m
COMMAND_METHODS =
['size'.freeze, 'first'.freeze, 'last'.freeze]

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(markup) ⇒ VariableLookup

Returns a new instance of VariableLookup



12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
# File 'lib/liquid/variable_lookup.rb', line 12

def initialize(markup)
  lookups = markup.scan(VariableParser)

  name = lookups.shift
  if name =~ SQUARE_BRACKETED
    name = Expression.parse($1)
  end
  @name = name

  @lookups = lookups
  @command_flags = 0

  @lookups.each_index do |i|
    lookup = lookups[i]
    if lookup =~ SQUARE_BRACKETED
      lookups[i] = Expression.parse($1)
    elsif COMMAND_METHODS.include?(lookup)
      @command_flags |= 1 << i
    end
  end
end

Instance Attribute Details

#lookupsObject (readonly)

Returns the value of attribute lookups



6
7
8
# File 'lib/liquid/variable_lookup.rb', line 6

def lookups
  @lookups
end

#nameObject (readonly)

Returns the value of attribute name



6
7
8
# File 'lib/liquid/variable_lookup.rb', line 6

def name
  @name
end

Class Method Details

.parse(markup) ⇒ Object



8
9
10
# File 'lib/liquid/variable_lookup.rb', line 8

def self.parse(markup)
  new(markup)
end

Instance Method Details

#==(other) ⇒ Object



72
73
74
# File 'lib/liquid/variable_lookup.rb', line 72

def ==(other)
  self.class == other.class && state == other.state
end

#evaluate(context) ⇒ Object



34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
# File 'lib/liquid/variable_lookup.rb', line 34

def evaluate(context)
  name = context.evaluate(@name)
  object = context.find_variable(name)

  @lookups.each_index do |i|
    key = context.evaluate(@lookups[i])

    # If object is a hash- or array-like object we look for the
    # presence of the key and if its available we return it
    if object.respond_to?(:[]) &&
        ((object.respond_to?(:key?) && object.key?(key)) ||
         (object.respond_to?(:fetch) && key.is_a?(Integer)))

      # if its a proc we will replace the entry with the proc
      res = context.lookup_and_evaluate(object, key)
      object = res.to_liquid

      # Some special cases. If the part wasn't in square brackets and
      # no key with the same name was found we interpret following calls
      # as commands and call them on the current object
    elsif @command_flags & (1 << i) != 0 && object.respond_to?(key)
      object = object.send(key).to_liquid

      # No key was present with the desired value and it wasn't one of the directly supported
      # keywords either. The only thing we got left is to return nil or
      # raise an exception if `strict_variables` option is set to true
    else
      return nil unless context.strict_variables
      raise Liquid::UndefinedVariable, "undefined variable #{key}"
    end

    # If we are dealing with a drop here we have to
    object.context = context if object.respond_to?(:context=)
  end

  object
end