class Puppet::Parser::AST
    # The base class for all of the leaves of the parse trees.  These
    # basically just have types and values.  Both of these parameters
    # are simple values, not AST objects.
    class Leaf < AST
        attr_accessor :value, :type

        # Return our value.
        def evaluate(scope)
            return @value
        end

        # evaluate ourselves, and match
        def evaluate_match(value, scope, options = {})
            obj = self.safeevaluate(scope)
            if ! options[:sensitive] && obj.respond_to?(:downcase)
                obj = obj.downcase
            end
            value = value.downcase if not options[:sensitive] and value.respond_to?(:downcase)
            obj == value
        end

        def match(value)
            @value == value
        end

        def to_s
            return @value.to_s unless @value.nil?
        end
    end

    # The boolean class.  True or false.  Converts the string it receives
    # to a Ruby boolean.
    class Boolean < AST::Leaf

        # Use the parent method, but then convert to a real boolean.
        def initialize(hash)
            super

            unless @value == true or @value == false
                raise Puppet::DevError,
                    "'%s' is not a boolean" % @value
            end
            @value
        end

        def to_s
            @value ? "true" : "false"
        end
    end

    # The base string class.
    class String < AST::Leaf
        # Interpolate the string looking for variables, and then return
        # the result.
        def evaluate(scope)
            return scope.strinterp(@value, file, line)
        end

        def to_s
            "\"#{@value}\""
        end
    end

    # An uninterpreted string.
    class FlatString < AST::Leaf
        def evaluate(scope)
            return @value
        end

        def to_s
            "\"#{@value}\""
        end
    end

    # The 'default' option on case statements and selectors.
    class Default < AST::Leaf; end

    # Capitalized words; used mostly for type-defaults, but also
    # get returned by the lexer any other time an unquoted capitalized
    # word is found.
    class Type < AST::Leaf; end

    # Lower-case words.
    class Name < AST::Leaf; end

    # double-colon separated class names
    class ClassName < AST::Leaf; end

    # undef values; equiv to nil
    class Undef < AST::Leaf; end

    # Host names, either fully qualified or just the short name, or even a regex
    class HostName < AST::Leaf
        def initialize(hash)
            super

            @value = @value.to_s.downcase unless @value.is_a?(Regex)
            if @value =~ /[^-\w.]/
                raise Puppet::DevError,
                    "'%s' is not a valid hostname" % @value
            end
        end

        def to_classname(dummy_argument=:work_arround_for_ruby_GC_bug)
            to_s.downcase.gsub(/[^-\w:.]/,'').sub(/^\.+/,'')
        end

        # implementing eql? and hash so that when an HostName is stored
        # in a hash it has the same hashing properties as the underlying value
        def eql?(value)
            value = value.value if value.is_a?(HostName)
            return @value.eql?(value)
        end

        def hash
            return @value.hash
        end

        def match(value)
            return @value.match(value) unless value.is_a?(HostName)

            if value.regex? and self.regex?
                # Wow this is some sweet design; maybe a touch of refactoring
                # in order here.
                return value.value.value == self.value.value
            elsif value.regex? # we know if the existing name is not a regex, it won't match a regex
                return false
            else
                # else, we could be either a regex or normal and it doesn't matter
                return @value.match(value.value)
            end
        end

        def regex?
            @value.is_a?(Regex)
        end

        def to_s
            @value.to_s
        end
    end

    # A simple variable.  This object is only used during interpolation;
    # the VarDef class is used for assignment.
    class Variable < Name
        # Looks up the value of the object in the scope tree (does
        # not include syntactical constructs, like '$' and '{}').
        def evaluate(scope)
            parsewrap do
                return scope.lookupvar(@value)
            end
        end

        def to_s
            "\$#{value}"
        end
    end

    class Regex < AST::Leaf
        def initialize(hash)
            super
            @value = Regexp.new(@value) unless @value.is_a?(Regexp)
        end

        # we're returning self here to wrap the regexp and to be used in places
        # where a string would have been used, without modifying any client code.
        # For instance, in many places we have the following code snippet:
        #  val = @val.safeevaluate(@scope)
        #  if val.match(otherval)
        #      ...
        #  end
        # this way, we don't have to modify this test specifically for handling
        # regexes.
        def evaluate(scope)
            return self
        end

        def evaluate_match(value, scope, options = {})
            value = value.is_a?(String) ? value : value.to_s

            if matched = @value.match(value)
                scope.ephemeral_from(matched, options[:file], options[:line])
            end
            matched
        end

        def match(value)
            @value.match(value)
        end

        def to_s
            return "/#{@value.source}/"
        end
    end
end