chervil/lib/chervil/ast/list.rb

module Chervil::AST
  class List
    attr_reader :elements

    def initialize(elements)
      @elements = elements
    end

    def ==(other)
      @elements == other.elements
    end

    def evaluate(env)
      if elements.empty?
        []
      else
        head = @elements.first
        if head.is_a?(Identifier)
          function = env.get(head.name)

          if function.nil?
            ::Chervil::Error.new("Unbound variable #{head.name}")
          else
            function.call(@elements[1..-1].map { |arg| arg.evaluate(env) }, env)
          end
        elsif head.is_a?(Function)
          head.call(@elements[1..-1].map { |arg| arg.evaluate(env) }, env)
        else
          @elements.map { |el| el.evaluate(env) }
        end
      end
    end
  end
end