Class: Liquid::Condition

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

Overview

Container for liquid nodes which conveniently wraps decision making logic

Example:

c = Condition.new(1, '==', 1)
c.evaluate #=> true

Direct Known Subclasses

ElseCondition

Defined Under Namespace

Classes: MethodLiteral, ParseTreeVisitor

Constant Summary collapse

@@operators =

:nodoc:

{
  '==' => ->(cond, left, right) {  cond.send(:equal_variables, left, right) },
  '!=' => ->(cond, left, right) { !cond.send(:equal_variables, left, right) },
  '<>' => ->(cond, left, right) { !cond.send(:equal_variables, left, right) },
  '<' => :<,
  '>' => :>,
  '>=' => :>=,
  '<=' => :<=,
  'contains' => lambda do |_cond, left, right|
    if left && right && left.respond_to?(:include?)
      right = right.to_s if left.is_a?(String)
      left.include?(right)
    else
      false
    end
  end,
}
@@method_literals = 
{
  'blank' => MethodLiteral.new(:blank?, '').freeze,
  'empty' => MethodLiteral.new(:empty?, '').freeze,
}

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(left = nil, operator = nil, right = nil) ⇒ Condition

Returns a new instance of Condition.



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# File 'lib/liquid/condition.rb', line 55

def initialize(left = nil, operator = nil, right = nil)
  @left     = left
  @operator = operator
  @right    = right

  @child_relation  = nil
  @child_condition = nil
end

Instance Attribute Details

#attachment ⇒ Object (readonly)

Returns the value of attribute attachment.



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# File 'lib/liquid/condition.rb', line 52

def attachment
  @attachment
end

#child_condition ⇒ Object (readonly)

Returns the value of attribute child_condition.



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# File 'lib/liquid/condition.rb', line 52

def child_condition
  @child_condition
end

#left ⇒ Object

Returns the value of attribute left.



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# File 'lib/liquid/condition.rb', line 53

def left
  @left
end

#operator ⇒ Object

Returns the value of attribute operator.



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# File 'lib/liquid/condition.rb', line 53

def operator
  @operator
end

#right ⇒ Object

Returns the value of attribute right.



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# File 'lib/liquid/condition.rb', line 53

def right
  @right
end

Class Method Details

.operators ⇒ Object 



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# File 'lib/liquid/condition.rb', line 44

def self.operators
  @@operators
end

.parse_expression(parse_context, markup) ⇒ Object 



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# File 'lib/liquid/condition.rb', line 48

def self.parse_expression(parse_context, markup)
  @@method_literals[markup] || parse_context.parse_expression(markup)
end

Instance Method Details

#and(condition) ⇒ Object 



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# File 'lib/liquid/condition.rb', line 88

def and(condition)
  @child_relation  = :and
  @child_condition = condition
end

#attach(attachment) ⇒ Object 



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# File 'lib/liquid/condition.rb', line 93

def attach(attachment)
  @attachment = attachment
end

#else? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/liquid/condition.rb', line 97

def else?
  false
end

#evaluate(context = deprecated_default_context) ⇒ Object 



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# File 'lib/liquid/condition.rb', line 64

def evaluate(context = deprecated_default_context)
  condition = self
  result = nil
  loop do
    result = interpret_condition(condition.left, condition.right, condition.operator, context)

    case condition.child_relation
    when :or
      break if result
    when :and
      break unless result
    else
      break
    end
    condition = condition.child_condition
  end
  result
end

#inspect ⇒ Object 



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# File 'lib/liquid/condition.rb', line 101

def inspect
  "#<Condition #{[@left, @operator, @right].compact.join(' ')}>"
end

#or(condition) ⇒ Object 



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# File 'lib/liquid/condition.rb', line 83

def or(condition)
  @child_relation  = :or
  @child_condition = condition
end