rule SetupObjectsDir
{
	# SetupObjectsDir
	#
	# Internal rule used to set up the *{LOCATE,SEARCH}*_{TARGET,SOURCE}
	# variables for the current directory.

	local relPath = [ FDirName $(SUBDIR_TOKENS[2-]) ] ;
	if $(relPath) = . {
		relPath = ;
	}
	COMMON_PLATFORM_LOCATE_TARGET =
		[ FDirName $(HAIKU_COMMON_PLATFORM_OBJECT_DIR) $(relPath) ] ;

	local var ;
	for var in COMMON_ARCH COMMON_DEBUG DEBUG_$(HAIKU_DEBUG_LEVELS) {
		HOST_$(var)_LOCATE_TARGET
			= [ FDirName $(HOST_$(var)_OBJECT_DIR) $(relPath) ] ;
		TARGET_$(var)_LOCATE_TARGET
			= [ FDirName $(TARGET_$(var)_OBJECT_DIR) $(relPath) ] ;
	}

	LOCATE_TARGET = $(COMMON_PLATFORM_LOCATE_TARGET) ;
	LOCATE_SOURCE = $(LOCATE_TARGET) ;
	SEARCH_SOURCE = $(SUBDIR) $(LOCATE_SOURCE)
		$(HOST_COMMON_DEBUG_LOCATE_TARGET)		# Also add the standard output
		$(TARGET_COMMON_DEBUG_LOCATE_TARGET)	# dirs for generated sources.
	;
}

rule SetupFeatureObjectsDir feature
{
	# SetupFeatureObjectsDir <feature>
	#
	# Updates the *{LOCATE,SEARCH}*_{TARGET,SOURCE} variables for the current
	# directory appending a <feature> to each of them. Note that it resets
	# the LOCATE_TARGET, LOCATE_SOURCE, SEARCH_SOURCE (!) variables. I.e. it
	# should be invoked before customizing these variables further (e.g. like
	# adding additional source directories to SEARCH_SOURCE).

	COMMON_PLATFORM_LOCATE_TARGET
		= [ FDirName $(COMMON_PLATFORM_LOCATE_TARGET) $(feature) ] ;

	local var ;
	for var in COMMON_ARCH COMMON_DEBUG DEBUG_$(HAIKU_DEBUG_LEVELS) {
		HOST_$(var)_LOCATE_TARGET
			= [ FDirName $(HOST_$(var)_LOCATE_TARGET) $(feature) ] ;
		TARGET_$(var)_LOCATE_TARGET
			= [ FDirName $(TARGET_$(var)_LOCATE_TARGET) $(feature) ] ;
	}

	LOCATE_TARGET = [ FDirName $(LOCATE_TARGET) $(feature) ] ;
	LOCATE_SOURCE = $(LOCATE_TARGET) ;
	SEARCH_SOURCE = $(SUBDIR) $(LOCATE_SOURCE)
		$(HOST_COMMON_DEBUG_LOCATE_TARGET)		# Also add the standard output
		$(TARGET_COMMON_DEBUG_LOCATE_TARGET)	# dirs for generated sources.
	;
}

rule SubIncludeGPL
{
	# SubInclude rule that can be used to conditionally include GPL licensed
	# add-ons
	if $(HAIKU_INCLUDE_GPL_ADDONS) = 1 {
		SubInclude $(1) ;
	}
}


# pragma mark - MakeLocate variants


rule MakeLocateCommonPlatform
{
	# The file is shared between all target platforms.
	MakeLocate $(1) : $(COMMON_PLATFORM_LOCATE_TARGET) ;
}

rule MakeLocatePlatform
{
	# The file is specific for the target platform, but
	# architecture independent. Usually the right rule for generated
	# sources, though sometimes sources can be architecture specific.
	local files = $(1) ;
	local file ;
	for file in $(files) {
		if [ on $(file) return $(PLATFORM) ] = host {
			MakeLocate $(file) : $(HOST_COMMON_ARCH_LOCATE_TARGET) ;
		} else {
			MakeLocate $(file) : $(TARGET_COMMON_ARCH_LOCATE_TARGET) ;
		}
	}
}

rule MakeLocateArch
{
	# The file is platform+architecture specific, but is debug
	# level independent. This is usually the right rule for generated
	# architecture specific data or source files.
	local files = $(1) ;
	local file ;
	for file in $(files) {
		if [ on $(file) return $(PLATFORM) ] = host {
			MakeLocate $(file) : $(HOST_COMMON_DEBUG_LOCATE_TARGET) ;
		} else {
			MakeLocate $(file) : $(TARGET_COMMON_DEBUG_LOCATE_TARGET) ;
		}
	}
}

rule MakeLocateDebug
{
	# The file is platform+architecture+debug level specific.
	# That's what should be used for compiled code.
	local files = $(1) ;
	local file ;
	for file in $(files) {
		on $(file) {
			if $(PLATFORM) = host {
				MakeLocate $(file) : $(HOST_DEBUG_$(DEBUG)_LOCATE_TARGET) ;
			} else {
				MakeLocate $(file) : $(TARGET_DEBUG_$(DEBUG)_LOCATE_TARGET) ;
			}
		}
	}
}


# pragma mark - Deferred SubIncludes


# The variable used to collect the deferred SubIncludes.
HAIKU_DEFERRED_SUB_INCLUDES = ;

rule DeferredSubInclude params : jamfile : scope
{
	# DeferredSubInclude <subdir tokens> [ : <jamfile name>  [ : <scope> ] ] ;
	#
	# Takes the same directory tokens parameter as SubInclude plus an optional
	# alternative Jamfile name. The the subdirectory referred to by
	# <subdir tokens> will be included when ExecuteDeferredSubIncludes is
	# invoked, i.e. at the end of the root Jamfile. The <jamfile name> parameter
	# specifies the name of the Jamfile to include. By default it is "Jamfile".
	# The <scope> parameter can be "global" (default) or "local", specifying
	# whether the alternative Jamfile name shall also be used for subdirectories.

	HAIKU_DEFERRED_SUB_INCLUDES += "/" $(params) ;
	if $(jamfile) {
		SetConfigVar JAMFILE : $(params) : $(jamfile) : $(scope) ;
	}
}

rule ExecuteDeferredSubIncludes
{
	# ExecuteDeferredSubIncludes ;
	#
	# Performs the deferred SubIncludes scheduled by DeferredSubInclude.

	local tokensList = $(HAIKU_DEFERRED_SUB_INCLUDES) ;
	while $(tokensList) {
		# chop off leading "/"
		tokensList = $(tokensList[2-]) ;

		# get the tokens for the next include
		local tokens ;
		while $(tokensList) && $(tokensList[1]) != "/" {
			tokens += $(tokensList[1]) ;
			tokensList = $(tokensList[2-]) ;
		}

		# perform the include
		if $(tokens) {
			SubInclude $(tokens) ;
		}
	}
}

rule HaikuSubInclude tokens
{
	# HaikuSubInclude <tokens> ;
	#
	# Current subdir relative SubInclude.
	# <tokens> - subdir tokens specifying the subdirectory to be include
	#            (relative to the current subdir)

	if $(tokens) {
		SubInclude HAIKU_TOP $(SUBDIR_TOKENS) $(tokens) ;
	}
}


# pragma mark - Unique IDs/targets


# private to NextID; incremented with each NextID invocation
HAIKU_NEXT_ID = 0 ;

rule NextID
{
	# NextID ;

	local result = $(HAIKU_NEXT_ID:J=) ;
	HAIKU_NEXT_ID = [ AddNumAbs $(HAIKU_NEXT_ID) : 1 ] ;
	return $(result) ;
}

rule NewUniqueTarget basename
{
	# NewUniqueTarget [ basename ] ;

	local id = [ NextID ] ;
	return $(basename[1]:E=_target:G=unique!target)_$(id) ;
}


# pragma mark - RunCommandLine


rule RunCommandLine commandLine
{
	# RunCommandLine <commandLine>
	#
	# Creates a pseudo target that, when made by jam, causes the supplied shell
	# command line to be executed. Elements of <commandLine> with the prefix ":"
	# are replaced by the rule. After stripping the prefix such a string specifies
	# a build system target and the finally executed command line will contain
	# a path to the target instead.
	# The pseudo target will depend on all targets thus identified. Each
	# invocation of this rule creates a different pseudo target, which is
	# returned to the caller.

	# collect the targets in the command line and replace them by $targetX*
	# variables
	local substitutedCommandLine ;
	local targets ;

	local targetVarName = target ;
	local i ;
	for i in $(commandLine)  {
		# targets are marked by the ":" prefix
		local target = [ Match ^:(.*) : $(i) ] ;
		if $(target) {
			targets += $(target) ;
			targetVarName = $(targetVarName)X ;
			i = "$"$(targetVarName) ;
		}

		substitutedCommandLine += $(i) ;
	}

	# define the "run" target
	local run = [ NewUniqueTarget run ] ;
	COMMAND_LINE on $(run) = $(substitutedCommandLine) ;
	NotFile $(run) ;
	Always $(run) ;
	Depends $(run) : $(targets) ;
	RunCommandLine1 $(run) : $(targets) ;

	return $(run) ;
}

actions RunCommandLine1 {
	target=target;
	for t in $(2) ; do
		target=${target}X
		eval "${target}=${t}"
	done
	$(HOST_ADD_BUILD_COMPATIBILITY_LIB_DIR)
	"$(COMMAND_LINE)"
}


#pragma mark - DefineBuildProfile


rule DefineBuildProfile name : type : path {
	# DefineBuildProfile <name> : <type> [ : <path> ]
	#
	# Makes a build profile known. Build profiles can be used to define
	# different sets of settings for Haiku images/installations. For each
	# profile the default actions "build", "update", and "mount" (the latter
	# only for disks or image types) will be available (i.e. can be specified
	# as second parameter on the jam command line). They will build an image
	# or installation, update only given targets, respectively just mount the
	# image or disk using the bfs_shell.
	#
	# <name> - The name of the build profile.
	# <type> - The type of the build profile. Must be one of "image" (plain
	#          disk image), "anyboot-image" (custom disk image that can be
	#          written to CD or disk device), "cd-image" (ISO CD image),
	#          "vmware-image" (VMware disk image), "disk" (actual partition
	#          or hard disk device), "install" (installation in a directory),
	#          or "custom" (user-defined).
	# <path> - The path associated with the profile. Depending on the profile
	#          type, this is the path to the disk image/VMware image, hard
	#          disk/partition device, or the installation directory. If the
	#          parameter is omitted, the value of the HAIKU[_VMWARE]_IMAGE_NAME,
	#          HAIKU_IMAGE_DIR, respectively HAIKU_INSTALL_DIR or their default
	#          values will be used instead.

	if [ on $(name) return $(HAIKU_BUILD_PROFILE_SPECIFIED) ] {
		Exit "ERROR: Build profile \"$(name)\" defined twice!" ;
	}
	HAIKU_BUILD_PROFILE_SPECIFIED on $(name) = 1 ;

	if ! $(HAIKU_BUILD_PROFILE) || $(HAIKU_BUILD_PROFILE) != $(name) {
		return ;
	}

	HAIKU_BUILD_PROFILE_DEFINED = 1 ;

	# split path into directory path and name
	local targetDir = $(path:D) ;
	local targetName = $(path:BS) ;

	# Jam's path splitting produces an empty string, if a component doesn't
	# exist. That's a little unhandy for checks.
	if $(targetDir) = "" {
		targetDir = ;
	}
	if $(targetName) = "" {
		targetName = ;
	}

	targetDir ?= $(HAIKU_IMAGE_DIR) ;
	targetDir ?= $(HAIKU_DEFAULT_IMAGE_DIR) ;

	# "disk" is "image" with HAIKU_DONT_CLEAR_IMAGE
	if $(type) = "disk" {
		type = "image" ;
		HAIKU_DONT_CLEAR_IMAGE = 1 ;
	}

	local buildTarget ;
	local startOffset ;

	switch $(type) {
		case "anyboot-image" : {
			targetName ?= $(HAIKU_ANYBOOT_NAME) ;
			targetName ?= $(HAIKU_DEFAULT_ANYBOOT_NAME) ;
			HAIKU_ANYBOOT_DIR = $(targetDir) ;
			HAIKU_ANYBOOT_NAME = $(targetName) ;
			buildTarget = haiku-anyboot-image ;
		}

		case "cd-image" : {
			targetName ?= $(HAIKU_CD_NAME) ;
			targetName ?= $(HAIKU_DEFAULT_CD_NAME) ;
			HAIKU_CD_DIR = $(targetDir) ;
			HAIKU_CD_NAME = $(targetName) ;
			buildTarget = haiku-cd ;
		}

		case "image" : {
			targetName ?= $(HAIKU_IMAGE_NAME) ;
			targetName ?= $(HAIKU_DEFAULT_IMAGE_NAME) ;
			HAIKU_IMAGE_DIR = $(targetDir) ;
			HAIKU_IMAGE_NAME = $(targetName) ;
			buildTarget = haiku-image ;
		}

		case "vmware-image" : {
			targetName ?= $(HAIKU_VMWARE_IMAGE_NAME) ;
			targetName ?= $(HAIKU_DEFAULT_VMWARE_IMAGE_NAME) ;
			HAIKU_IMAGE_DIR = $(targetDir) ;
			HAIKU_VMWARE_IMAGE_NAME = $(targetName) ;
			buildTarget = haiku-vmware-image ;
			startOffset = --start-offset 65536 ;
		}

		case "install" : {
			path ?= $(HAIKU_INSTALL_DIR) ;
			path ?= $(HAIKU_DEFAULT_INSTALL_DIR) ;
			HAIKU_INSTALL_DIR = $(path) ;
			buildTarget = install-haiku ;
		}

		case "custom" : {
			# user-defined -- don't do anything
			return 1 ;
		}

		case * : {
			Exit "Unsupported build profile type: " $(type) ;
		}
	}

	switch $(HAIKU_BUILD_PROFILE_ACTION) {
		case "build" : {
			JAM_TARGETS = $(buildTarget) ;
		}

		case "update" : {
			JAM_TARGETS = $(buildTarget) ;
			SetUpdateHaikuImageOnly 1 ;
			HAIKU_PACKAGES_UPDATE_ONLY = 1 ;
			HAIKU_INCLUDE_IN_IMAGE on $(HAIKU_BUILD_PROFILE_PARAMETERS) = 1 ;
			HAIKU_INCLUDE_IN_PACKAGES on $(HAIKU_BUILD_PROFILE_PARAMETERS) = 1 ;
		}

		case "update-all" : {
			JAM_TARGETS = $(buildTarget) ;
			SetUpdateHaikuImageOnly 1 ;
			HAIKU_PACKAGES_UPDATE_ONLY = 1 ;
			HAIKU_INCLUDE_IN_IMAGE = 1 ;
			HAIKU_INCLUDE_IN_PACKAGES = 1 ;
		}

		case "update-packages" : {
			JAM_TARGETS = $(buildTarget) ;
			SetUpdateHaikuImageOnly 1 ;
			HAIKU_UPDATE_ALL_PACKAGES = 1 ;
		}

		case "mount" : {
			if $(type) in "install" "cd-image" {
				Exit "Build action \"mount\" not supported for profile type"
					"\"$(type)\"." ;
			}

			local commandLine = :<build>bfs_shell $(startOffset)
				\"$(targetName:D=$(targetDir))\" ;
			JAM_TARGETS = [ RunCommandLine $(commandLine) ] ;
		}
	}

	return 1 ;
}


# pragma mark - Build Features


rule FIsBuildFeatureEnabled feature
{
	# FIsBuildFeatureEnabled <feature> ;
	# Returns whether the given build feature <feature> is enabled (if so: "1",
	# if not: empty list).
	#
	# <feature> - The name of the build feature (all lower case).

	if $(feature) in $(HAIKU_BUILD_FEATURES) {
		return 1 ;
	}

	return ;
}


rule FMatchesBuildFeatures specification
{
	# FMatchesBuildFeatures <specification> ;
	# Returns whether the given build feature specification <specification>
	# holds. <specification> consists of positive and negative build feature
	# conditions. Conditions can be individual list elements and multiple
	# conditions can be joined, separated by ",", in a single list element. The
	# effect is the same; they are considered as single set of conditions.
	# A positive condition does not start with a "!". It holds when the build
	# feature named by the element is enabled.
	# A negative condition starts with a "!". It holds when the build feature
	# named by the string resulting from removing the leading "!" is not
	# enabled.
	# <specification> holds when it is not empty and
	# * none of the negative conditions it contains hold and
	# * if it contains any positive conditions, at least one one of them holds.
	#
	# <specification> - The build feature specification. A list of individual
	#	conditions or conditions joined by ",".

	local splitSpecification ;
	local element ;
	for element in $(specification) {
		splitSpecification += [ FSplitString $(element) : "," ] ;
	}
	return [ FSetConditionsHold $(splitSpecification)
		: $(HAIKU_BUILD_FEATURES) ] ;
}


rule FFilterByBuildFeatures list
{
	# FFilterByBuildFeatures <list> ;
	# Filters the list annotated by build feature specifications and returns the
	# resulting list. The list can be annotated in two different ways:
	# * A single list element can be annotated by appending "@<specification>"
	#   to it, with <specification> being a build feature specification (a
	#   single comma-separated string). The element appears in the resulting
	#   list, only if <specification> holds.
	# * A sublist can be annotated by enclosing it in "<specification> @{" (two
	#   separate list elements) and "}@", with <specification> being a build
	#   feature specification (a single comma-separated string). The enclosed
	#   sublist appears in the resulting list, only if <specification> holds.
	# The sublist annotations can be nested. The annotations themselves don't
	# appear in the resulting list.
	#
	# <list> - A list annotated with build feature specifications.

	local filteredList ;

	# Since we must look ahead one element to be able to decide whether an
	# element is a regular list element or a features specification for a
	# subsequent "@{". Hence we always process an element other than "@{" and
	# "}@" in the next iteration. We append a dummy element to the list so we
	# don't need special handling for the last element.
	local evaluationStack = 1 ;
	local previousElement ;
	local element ;
	for element in $(list) dummy {
		local stackTop = $(evaluationStack[1]) ;
		local processElement = $(previousElement) ;
		switch $(element) {
			case }@ :
			{
				# Pop the topmost specification off the stack.
				evaluationStack = $(evaluationStack[2-]) ;
				if ! $(evaluationStack) {
					Exit "FFilterByBuildFeatures: Unbalanced @( in: " $(list) ;
				}

				processElement = $(previousElement) ;
				previousElement = ;
			}
			case @{ :
			{
				if ! $(previousElement) {
					Exit "FFilterByBuildFeatures: No feature specification"
						"after )@ in: " $(list) ;
				}

				if $(evaluationStack[1]) = 1
					&& [ FMatchesBuildFeatures $(previousElement) ] {
					evaluationStack = 1 $(evaluationStack) ;
				} else {
					evaluationStack = 0 $(evaluationStack) ;
				}

				processElement = ;
				previousElement = ;
			}
			case * :
			{
				processElement = $(previousElement) ;
				previousElement = $(element) ;
			}
		}

		if $(processElement) && $(stackTop) = 1 {
			local splitElement = [ Match "(.*)@([^@]*)" : $(processElement) ] ;
			if $(splitElement) {
				if [ FMatchesBuildFeatures $(splitElement[2]) ] {
					filteredList += $(splitElement[1]) ;
				}
			} else {
				filteredList += $(processElement) ;
			}
		}
	}

	if $(evaluationStack[2-]) {
		Exit "FFilterByBuildFeatures: Unbalanced )@ in: " $(list) ;
	}

	return $(filteredList) ;
}


rule EnableBuildFeatures features : specification
{
	# EnableBuildFeatures <features> : <specification> ;
	# Enables the build features <features>, if the build features specification
	# <specification> holds. If <specification> is omitted, the features are
	# enabled unconditionally.
	# The rule enables a build feature by adding its given lower case name to
	# the build variable HAIKU_BUILD_FEATURES and defining a build variable
	# HAIKU_BUILD_FEATURE_<FEATURE>_ENABLED (<FEATURE> being the upper case name
	# of the build feature) to "1".
	#
	# <features> - A list of build feature names (lower case).
	# <specification> - An optional build features specification (cf.
	#	FMatchesBuildFeatures).

	if ! $(specification)
		|| [ FMatchesBuildFeatures $(specification)
			: $(HAIKU_BUILD_FEATURES) ] {
		local feature ;
		for feature in $(features) {
			HAIKU_BUILD_FEATURES += $(feature) ;
			HAIKU_BUILD_FEATURE_$(feature:U)_ENABLED = 1 ;
		}
	}
}


rule BuildFeatureObject feature
{
	# BuildFeatureObject <feature> ;
	# Returns a unique object for the given build feature. It is used for
	# attaching attribute values to it.

	local featureObject = $(HAIKU_BUILD_FEATURE_$(feature:U)) ;
	if ! $(featureObject) {
		featureObject = [ NewUniqueTarget ] ;
		HAIKU_BUILD_FEATURE_$(feature:U) = $(featureObject) ;
	}

	return $(featureObject) ;
}


rule SetBuildFeatureAttribute feature : attribute : values : package
{
	# SetBuildFeatureAttribute <feature> : <attribute> : <values>
	#	[ : <package> ] ;
	# Sets attribute <attribute> of a build feature <feature> to value <values>.
	# If <package> is specified, it names the package the attribute belongs to.

	local featureObject = [ BuildFeatureObject $(feature) ] ;
	HAIKU_ATTRIBUTE_$(attribute) on $(featureObject) = $(values) ;
	if $(package) {
		HAIKU_ATTRIBUTE_$(attribute):package on $(featureObject) = $(package) ;
	}
}


rule BuildFeatureAttribute feature : attribute : flags
{
	# BuildFeatureAttribute <feature> : <attribute> [ : <flags> ] ;
	# Returns the value of attribute <attribute> of a build feature <feature>.
	# Flags can be a list of flags which influence the returned value. Currently
	# only flag "path" is defined, which will convert the attribute value --
	# which is assumed to be a list of (gristed) targets with a path relative to
	# the extraction directory of the build feature archive files -- to paths.
	# A typical example is the "headers" attribute, whose value can be used as
	# dependency, but which must be converted to a path to be a valid headers
	# search path.

	local featureObject = [ BuildFeatureObject $(feature) ] ;
	local values
		= [ on $(featureObject) return $(HAIKU_ATTRIBUTE_$(attribute)) ] ;
	if path in $(flags) {
		# get the attribute's package and the corresponding extraction dir
		local package
			= [ BuildFeatureAttribute $(feature) : $(attribute):package ] ;
		local directory ;
		if $(package) {
			directory = [ BuildFeatureAttribute $(feature)
				: $(package):directory ] ;
		}

		# translate the values
		local paths ;
		local value ;
		for value in $(values:G=) {
			paths += [ FDirName $(directory) $(value) ] ;
		}
		values = $(paths) ;
	}

	return $(values) ;
}


rule ExtractBuildFeatureArchives feature : list
{
	# ExtractBuildFeatureArchives <feature> : <list> ;
	# Downloads and extracts one or more archives for build feature <feature>
	# and sets attributes for the build feature to extracted entries. The syntax
	# for <list> is:
	# "file:" <packageName> <url>
	#    <attribute>: <value> ...
	#    ...
	# "file:" <packageName2> <url2>
	# ...
	#
	# <packageName> specifies a short name for the archive (e.g. "base" for the
	# base package, "devel" for the development package, etc.), <url> the URL
	# from which to download the file. <attribute> and be any name and <value>
	# any relative path in the extraction directory.
	#
	# The attribute with the name "depends" will be handled specially. Its
	# <value> specifies the name of a package the current package depends on
	# (e.g. "devel" typically depends on "base"). If such a dependency is
	# specified the current package will be extracted to the same directory as
	# the package it depends on. The "depends" attribute must precede any other
	# attribute for the package.
	#
	# The rule also sets the build feature attribute "<packageName>:directory"
	# to the extraction directory for each package.

	while $(list) {
		if $(list[1]) != file: {
			Exit "ExtractBuildFeatureArchives: Expected \"file: ...\", got:"
				$(list) ;
		}

		local package = $(list[2]) ;
		local url = $(list[3]) ;
		local fileName = $(url:BS) ;
		list = $(list[4-]) ;

		local file = [ DownloadFile $(fileName) : $(url) ] ;

		local directory = [ FDirName $(HAIKU_OPTIONAL_BUILD_PACKAGES_DIR)
			$(fileName:B) ] ;
		directory = $(directory:G=$(package)) ;

		while $(list) {
			local attribute = [ Match "(.*):" : $(list[1]) ] ;
			if ! $(attribute) {
				Exit "ExtractBuildFeatureArchives: Expected attribute, got:"
					$(list) ;
			}
			if $(attribute) = file {
				break ;
			}

			list = $(list[2-]) ;

			local values ;

			while $(list) {
				switch $(list[1]) {
					case *: :
					{
						break ;
					}
					case * :
					{
						values += $(list[1]) ;
						list = $(list[2-]) ;
					}
				}
			}

			if $(attribute) = depends {
				# Inherit the extraction directory (with a different grist) and
				# depend on the extraction directory of the base package.
				local basePackage = $(values[1]) ;
				local baseDirectory = [ BuildFeatureAttribute $(feature)
					: $(basePackage):directory ] ;
				directory = $(baseDirectory:G=$(package)) ;
				Depends $(directory) : $(directory:G=$(basePackage)) ;
			} else {
				SetBuildFeatureAttribute $(feature) : $(attribute)
					: [ ExtractArchive $(directory)
						: $(values) : $(file)
						: extracted-$(feature)-$(package) ] ;
				SetBuildFeatureAttribute $(feature) : $(attribute):package
					: $(package) ;
			}
		}

		SetBuildFeatureAttribute $(feature) : $(package):directory
			: $(directory:G=) ;
	}
}