Contents

module PAC
  module Runtimes
    class JohnsonRuntime
      class Context
        def initialize(source = "")
          @runtime = ::Johnson::Runtime.new
          @runtime.evaluate(source)
        end

        def include(mod)
          (mod.methods - Module.methods).each do |name|
            @runtime[name] = mod.method(name)
          end
        end

        def call(properties, *args)
          unbox @runtime.evaluate(properties).call(*args)
        rescue Johnson::Error => e
          if syntax_error?(e)
            raise RuntimeError, e.message
          else
            raise ProgramError, e.message
          end
        end

        def unbox(value)
          case
          when function?(value)
            nil
          when string?(value)
            value.respond_to?(:force_encoding) ? value.force_encoding("UTF-8") : value
          when array?(value)
            value.map { |v| unbox(v) }
          when object?(value)
            value.inject({}) do |vs, (k, v)|
              vs[k] = unbox(v) unless function?(v)
              vs
            end
          else
            value
          end
        end

        private
          def syntax_error?(error)
            error.message =~ /^syntax error at /
          end

          def function?(value)
            value.respond_to?(:function?) && value.function?
          end

          def string?(value)
            value.is_a?(String)
          end

          def array?(value)
            array_test.call(value)
          end

          def object?(value)
            value.respond_to?(:inject)
          end

          def array_test
            @array_test ||= @runtime.evaluate("(function(a) { return a instanceof [].constructor})")
          end
      end

      def name
        "Johnson (SpiderMonkey)"
      end

      def compile(source)
        Context.new(source)
      end

      def available?
        require "johnson"
        true
      rescue LoadError
        false
      end
    end
  end
end

Version data entries

1 entries across 1 versions & 1 rubygems

Version	Path
pac-1.0.0	lib/pac/runtimes/johnson.rb