class Liquid::If

@liquid_public_docs @liquid_type tag @liquid_category conditional @liquid_name if @liquid_summary

Renders an expression if a specific condition is `true`.

@liquid_syntax

{% if condition %}
  expression
{% endif %}

@liquid_syntax_keyword condition The condition to evaluate. @liquid_syntax_keyword expression The expression to render if the condition is met.

Constants

BOOLEAN_OPERATORS
ELSE_TAG_NAMES
ExpressionsAndOperators
Syntax

Attributes

blocks[R]

Public Class Methods

new(tag_name, markup, options) click to toggle source
Calls superclass method Liquid::Block::new
# File lib/liquid/tags/if.rb, line 23
def initialize(tag_name, markup, options)
  super
  @blocks = []
  push_block('if', markup)
end

Public Instance Methods

nodelist() click to toggle source
# File lib/liquid/tags/if.rb, line 29
def nodelist
  @blocks.map(&:attachment)
end
parse(tokens) click to toggle source
# File lib/liquid/tags/if.rb, line 33
def parse(tokens)
  while parse_body(@blocks.last.attachment, tokens)
  end
  @blocks.reverse_each do |block|
    block.attachment.remove_blank_strings if blank?
    block.attachment.freeze
  end
end
render_to_output_buffer(context, output) click to toggle source
# File lib/liquid/tags/if.rb, line 53
def render_to_output_buffer(context, output)
  @blocks.each do |block|
    result = Liquid::Utils.to_liquid_value(
      block.evaluate(context),
    )

    if result
      return block.attachment.render_to_output_buffer(context, output)
    end
  end

  output
end
unknown_tag(tag, markup, tokens) click to toggle source
Calls superclass method Liquid::Block#unknown_tag
# File lib/liquid/tags/if.rb, line 45
def unknown_tag(tag, markup, tokens)
  if ELSE_TAG_NAMES.include?(tag)
    push_block(tag, markup)
  else
    super
  end
end

Private Instance Methods

lax_parse(markup) click to toggle source
# File lib/liquid/tags/if.rb, line 84
def lax_parse(markup)
  expressions = markup.scan(ExpressionsAndOperators)
  raise SyntaxError, options[:locale].t("errors.syntax.if") unless expressions.pop =~ Syntax

  condition = Condition.new(parse_expression(Regexp.last_match(1)), Regexp.last_match(2), parse_expression(Regexp.last_match(3)))

  until expressions.empty?
    operator = expressions.pop.to_s.strip

    raise SyntaxError, options[:locale].t("errors.syntax.if") unless expressions.pop.to_s =~ Syntax

    new_condition = Condition.new(parse_expression(Regexp.last_match(1)), Regexp.last_match(2), parse_expression(Regexp.last_match(3)))
    raise SyntaxError, options[:locale].t("errors.syntax.if") unless BOOLEAN_OPERATORS.include?(operator)
    new_condition.send(operator, condition)
    condition = new_condition
  end

  condition
end
parse_binary_comparisons(p) click to toggle source
# File lib/liquid/tags/if.rb, line 111
def parse_binary_comparisons(p)
  condition = parse_comparison(p)
  first_condition = condition
  while (op = p.id?('and') || p.id?('or'))
    child_condition = parse_comparison(p)
    condition.send(op, child_condition)
    condition = child_condition
  end
  first_condition
end
parse_comparison(p) click to toggle source
# File lib/liquid/tags/if.rb, line 122
def parse_comparison(p)
  a = parse_expression(p.expression)
  if (op = p.consume?(:comparison))
    b = parse_expression(p.expression)
    Condition.new(a, op, b)
  else
    Condition.new(a)
  end
end
parse_expression(markup) click to toggle source
# File lib/liquid/tags/if.rb, line 80
def parse_expression(markup)
  Condition.parse_expression(parse_context, markup)
end
push_block(tag, markup) click to toggle source
# File lib/liquid/tags/if.rb, line 69
def push_block(tag, markup)
  block = if tag == 'else'
    ElseCondition.new
  else
    parse_with_selected_parser(markup)
  end

  @blocks.push(block)
  block.attach(new_body)
end
strict_parse(markup) click to toggle source
# File lib/liquid/tags/if.rb, line 104
def strict_parse(markup)
  p = Parser.new(markup)
  condition = parse_binary_comparisons(p)
  p.consume(:end_of_string)
  condition
end