Class: Liquid::Expression

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

Constant Summary collapse

LITERALS = 
{
  nil => nil, 'nil' => nil, 'null' => nil, '' => nil,
  'true' => true,
  'false' => false,
  'blank' => '',
  'empty' => ''
}.freeze
INTEGERS_REGEX = 
/\A(-?\d+)\z/
FLOATS_REGEX = 
/\A(-?\d[\d\.]+)\z/
RANGES_REGEX =

Use an atomic group (?>…) to avoid pathological backtracing from malicious input as described in github.com/Shopify/liquid/issues/1357

/\A\(\s*(?>(\S+)\s*\.\.)\s*(\S+)\s*\)\z/

Class Method Summary collapse

Class Method Details

.parse(markup) ⇒ Object 



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# File 'lib/liquid/expression.rb', line 20

def self.parse(markup)
  return nil unless markup

  markup = markup.strip
  if (markup.start_with?('"') && markup.end_with?('"')) ||
     (markup.start_with?("'") && markup.end_with?("'"))
    return markup[1..-2]
  end

  case markup
  when INTEGERS_REGEX
    Regexp.last_match(1).to_i
  when RANGES_REGEX
    RangeLookup.parse(Regexp.last_match(1), Regexp.last_match(2))
  when FLOATS_REGEX
    Regexp.last_match(1).to_f
  else
    if LITERALS.key?(markup)
      LITERALS[markup]
    else
      VariableLookup.parse(markup)
    end
  end
end