module Bridgetown::Filters::ConditionHelpers

Public Instance Methods

parse_binary_comparison(parser) click to toggle source

Generate a Liquid::Condition object from a Liquid::Parser object additionally processing the parsed expression based on whether the expression consists of binary operations with Liquid operators `and` or `or`

- parser: an instance of Liquid::Parser

Returns an instance of Liquid::Condition

# File lib/bridgetown-core/filters/condition_helpers.rb, line 25
def parse_binary_comparison(parser)
  condition = parse_comparison(parser)
  first_condition = condition
  while (binary_operator = parser.id?("and") || parser.id?("or"))
    child_condition = parse_comparison(parser)
    condition.send(binary_operator, child_condition)
    condition = child_condition
  end
  first_condition
end
parse_comparison(parser) click to toggle source

Generates a Liquid::Condition object from a Liquid::Parser object based on whether the parsed expression involves a “comparison” operator (e.g. <, ==, >, !=, etc)

- parser: an instance of Liquid::Parser

Returns an instance of Liquid::Condition

# File lib/bridgetown-core/filters/condition_helpers.rb, line 43
def parse_comparison(parser)
  left_operand = Liquid::Expression.parse(parser.expression)
  operator     = parser.consume?(:comparison)

  # No comparison-operator detected. Initialize a Liquid::Condition using only left operand
  return Liquid::Condition.new(left_operand) unless operator

  # Parse what remained after extracting the left operand and the `:comparison` operator
  # and initialize a Liquid::Condition object using the operands and the comparison-operator
  Liquid::Condition.new(left_operand, operator, Liquid::Expression.parse(parser.expression))
end
parse_condition(exp) click to toggle source

Parse a string to a Liquid Condition

# File lib/bridgetown-core/filters/condition_helpers.rb, line 10
def parse_condition(exp)
  parser    = Liquid::Parser.new(exp)
  condition = parse_binary_comparison(parser)

  parser.consume(:end_of_string)
  condition
end