eclass/python-single-r1.eclass - mirrors/cros/chromiumos/overlays/portage-stable - Git at Google

 # Copyright 1999-2015 Gentoo Foundation
 # Distributed under the terms of the GNU General Public License v2
 # $Header: /var/cvsroot/gentoo-x86/eclass/python-single-r1.eclass,v 1.36 2015/02/20 17:57:22 mgorny Exp $

 # @ECLASS: python-single-r1
 # @MAINTAINER:
 # Python team <python@gentoo.org>
 # @AUTHOR:
 # Author: Michał Górny <mgorny@gentoo.org>
 # Based on work of: Krzysztof Pawlik <nelchael@gentoo.org>
 # @BLURB: An eclass for Python packages not installed for multiple implementations.
 # @DESCRIPTION:
 # An extension of the python-r1 eclass suite for packages which
 # don't support being installed for multiple Python implementations.
 # This mostly includes tools embedding Python.
 #
 # This eclass extends the IUSE and REQUIRED_USE set by python-r1
 # to request the PYTHON_SINGLE_TARGET when the inheriting ebuild
 # can be supported by more than one Python implementation. It also
 # replaces PYTHON_USEDEP and PYTHON_DEPS with a more suitable form.
 #
 # Please note that packages support multiple Python implementations
 # (using python-r1 eclass) can not depend on packages not supporting
 # them (using this eclass).
 #
 # Please note that python-single-r1 will always inherit python-utils-r1
 # as well. Thus, all the functions defined there can be used
 # in the packages using python-single-r1, and there is no need ever
 # to inherit both.
 #
 # For more information, please see the python-r1 Developer's Guide:
 # http://www.gentoo.org/proj/en/Python/python-r1/dev-guide.xml

 case "${EAPI:-0}" in
 	0|1|2|3)
 		die "Unsupported EAPI=${EAPI:-0} (too old) for ${ECLASS}"
 		;;
 	4|5)
 		# EAPI=4 is required for USE default deps on USE_EXPAND flags
 		;;
 	*)
 		die "Unsupported EAPI=${EAPI} (unknown) for ${ECLASS}"
 		;;
 esac

 if [[ ! ${_PYTHON_SINGLE_R1} ]]; then

 if [[ ${_PYTHON_R1} ]]; then
 	die 'python-single-r1.eclass can not be used with python-r1.eclass.'
 elif [[ ${_PYTHON_ANY_R1} ]]; then
 	die 'python-single-r1.eclass can not be used with python-any-r1.eclass.'
 fi

 inherit python-utils-r1

 fi

 EXPORT_FUNCTIONS pkg_setup

 if [[ ! ${_PYTHON_SINGLE_R1} ]]; then

 # @ECLASS-VARIABLE: PYTHON_COMPAT
 # @REQUIRED
 # @DESCRIPTION:
 # This variable contains a list of Python implementations the package
 # supports. It must be set before the `inherit' call. It has to be
 # an array.
 #
 # Example:
 # @CODE
 # PYTHON_COMPAT=( python{2_5,2_6,2_7} )
 # @CODE
 if ! declare -p PYTHON_COMPAT &>/dev/null; then
 	die 'PYTHON_COMPAT not declared.'
 fi

 # @ECLASS-VARIABLE: PYTHON_REQ_USE
 # @DEFAULT_UNSET
 # @DESCRIPTION:
 # The list of USEflags required to be enabled on the chosen Python
 # implementations, formed as a USE-dependency string. It should be valid
 # for all implementations in PYTHON_COMPAT, so it may be necessary to
 # use USE defaults.
 #
 # This should be set before calling `inherit'.
 #
 # Example:
 # @CODE
 # PYTHON_REQ_USE="gdbm,ncurses(-)?"
 # @CODE
 #
 # It will cause the Python dependencies to look like:
 # @CODE
 # python_single_target_pythonX_Y? ( dev-lang/python:X.Y[gdbm,ncurses(-)?] )
 # @CODE

 # @ECLASS-VARIABLE: PYTHON_DEPS
 # @DESCRIPTION:
 # This is an eclass-generated Python dependency string for all
 # implementations listed in PYTHON_COMPAT.
 #
 # The dependency string is conditional on PYTHON_SINGLE_TARGET.
 #
 # Example use:
 # @CODE
 # RDEPEND="${PYTHON_DEPS}
 #	dev-foo/mydep"
 # DEPEND="${RDEPEND}"
 # @CODE
 #
 # Example value:
 # @CODE
 # dev-lang/python-exec:=
 # python_single_target_python2_6? ( dev-lang/python:2.6[gdbm] )
 # python_single_target_python2_7? ( dev-lang/python:2.7[gdbm] )
 # @CODE

 # @ECLASS-VARIABLE: PYTHON_USEDEP
 # @DESCRIPTION:
 # This is an eclass-generated USE-dependency string which can be used to
 # depend on another Python package being built for the same Python
 # implementations.
 #
 # The generate USE-flag list is compatible with packages using python-r1,
 # python-single-r1 and python-distutils-ng eclasses. It must not be used
 # on packages using python.eclass.
 #
 # Example use:
 # @CODE
 # RDEPEND="dev-python/foo[${PYTHON_USEDEP}]"
 # @CODE
 #
 # Example value:
 # @CODE
 # python_targets_python2_7(-)?,python_single_target_python2_7(+)?
 # @CODE

 # @ECLASS-VARIABLE: PYTHON_REQUIRED_USE
 # @DESCRIPTION:
 # This is an eclass-generated required-use expression which ensures the following
 # when more than one python implementation is possible:
 # 1. Exactly one PYTHON_SINGLE_TARGET value has been enabled.
 # 2. The selected PYTHON_SINGLE_TARGET value is enabled in PYTHON_TARGETS.
 #
 # This expression should be utilized in an ebuild by including it in
 # REQUIRED_USE, optionally behind a use flag.
 #
 # Example use:
 # @CODE
 # REQUIRED_USE="python? ( ${PYTHON_REQUIRED_USE} )"
 # @CODE
 #
 # Example value:
 # @CODE
 # python_single_target_python2_6? ( python_targets_python2_6 )
 # python_single_target_python2_7? ( python_targets_python2_7 )
 # ^^ ( python_single_target_python2_6 python_single_target_python2_7 )
 # @CODE

 _python_single_set_globals() {
 	local impls=()
 	local unimpls=()

 	PYTHON_DEPS=
 	local i PYTHON_PKG_DEP
 	for i in "${_PYTHON_ALL_IMPLS[@]}"; do
 		has "${i}" "${PYTHON_COMPAT[@]}" \
 			&& impls+=( "${i}" ) \
 			|| unimpls+=( "${i}" )
 	done

 	if [[ ${#impls[@]} -eq 0 ]]; then
 		die "No supported implementation in PYTHON_COMPAT."
 	fi

 	local flags_mt=( "${impls[@]/#/python_targets_}" )
 	local flags=( "${impls[@]/#/python_single_target_}" )
 	local unflags=( "${unimpls[@]/#/-python_single_target_}" )

 	local optflags=${flags_mt[@]/%/(-)?},${unflags[@]/%/(-)}

 	IUSE="${flags_mt[*]}"

 	if [[ ${#impls[@]} -eq 1 ]]; then
 		# There is only one supported implementation; set IUSE and other
 		# variables without PYTHON_SINGLE_TARGET.
 		PYTHON_REQUIRED_USE="${flags_mt[*]}"
 		python_export "${impls[0]}" PYTHON_PKG_DEP
 		PYTHON_DEPS="${PYTHON_PKG_DEP} "
 		# Force on the python_single_target_* flag for this impl, so
 		# that any dependencies that inherit python-single-r1 and
 		# happen to have multiple implementations will still need
 		# to bound by the implementation used by this package.
 		optflags+=,${flags[0]/%/(+)}
 	else
 		# Multiple supported implementations; honor PYTHON_SINGLE_TARGET.
 		IUSE+=" ${flags[*]}"
 		PYTHON_REQUIRED_USE="^^ ( ${flags[*]} )"
 		# Ensure deps honor the same python_single_target_* flag as is set
 		# on this package.
 		optflags+=,${flags[@]/%/(+)?}

 		for i in "${impls[@]}"; do
 			# The chosen targets need to be in PYTHON_TARGETS as well.
 			# This is in order to enforce correct dependencies on packages
 			# supporting multiple implementations.
 			PYTHON_REQUIRED_USE+=" python_single_target_${i}? ( python_targets_${i} )"

 			python_export "${i}" PYTHON_PKG_DEP
 			PYTHON_DEPS+="python_single_target_${i}? ( ${PYTHON_PKG_DEP} ) "
 		done
 	fi
 	PYTHON_USEDEP=${optflags// /,}

 	# 1) well, python-exec would suffice as an RDEP
 	# but no point in making this overcomplex, BDEP doesn't hurt anyone
 	# 2) python-exec should be built with all targets forced anyway
 	# but if new targets were added, we may need to force a rebuild
 	# 3) use whichever python-exec slot installed in EAPI 5. For EAPI 4,
 	# just fix :2 since := deps are not supported.
 	if [[ ${_PYTHON_WANT_PYTHON_EXEC2} == 0 ]]; then
 		die "python-exec:0 is no longer supported, please fix your ebuild to work with python-exec:2"
 	elif [[ ${EAPI} != 4 ]]; then
 		PYTHON_DEPS+=">=dev-lang/python-exec-2:=[${PYTHON_USEDEP}]"
 	else
 		PYTHON_DEPS+="dev-lang/python-exec:2[${PYTHON_USEDEP}]"
 	fi
 }
 _python_single_set_globals

 # @FUNCTION: python_gen_usedep
 # @USAGE: <pattern> [...]
 # @DESCRIPTION:
 # Output a USE dependency string for Python implementations which
 # are both in PYTHON_COMPAT and match any of the patterns passed
 # as parameters to the function.
 #
 # Remember to escape or quote the patterns to prevent shell filename
 # expansion.
 #
 # When all implementations are requested, please use ${PYTHON_USEDEP}
 # instead. Please also remember to set an appropriate REQUIRED_USE
 # to avoid ineffective USE flags.
 #
 # Example:
 # @CODE
 # PYTHON_COMPAT=( python{2_7,3_4} )
 # DEPEND="doc? ( dev-python/epydoc[$(python_gen_usedep 'python2*')] )"
 # @CODE
 #
 # It will cause the dependency to look like:
 # @CODE
 # DEPEND="doc? ( dev-python/epydoc[python_targets_python2_7(-)?,...] )"
 # @CODE
 python_gen_usedep() {
 	debug-print-function ${FUNCNAME} "${@}"

 	local impl pattern
 	local matches=()

 	for impl in "${PYTHON_COMPAT[@]}"; do
 		_python_impl_supported "${impl}" || continue

 		for pattern; do
 			if [[ ${impl} == ${pattern} ]]; then
 				matches+=(
 					"python_targets_${impl}(-)?"
 					"python_single_target_${impl}(+)?"
 				)
 				break
 			fi
 		done
 	done

 	[[ ${matches[@]} ]] || die "No supported implementations match python_gen_usedep patterns: ${@}"

 	local out=${matches[@]}
 	echo "${out// /,}"
 }

 # @FUNCTION: python_gen_useflags
 # @USAGE: <pattern> [...]
 # @DESCRIPTION:
 # Output a list of USE flags for Python implementations which
 # are both in PYTHON_COMPAT and match any of the patterns passed
 # as parameters to the function.
 #
 # Example:
 # @CODE
 # PYTHON_COMPAT=( python{2_7,3_4} )
 # REQUIRED_USE="doc? ( ^^ ( $(python_gen_useflags 'python2*') ) )"
 # @CODE
 #
 # It will cause the variable to look like:
 # @CODE
 # REQUIRED_USE="doc? ( ^^ ( python_single_target_python2_7 ) )"
 # @CODE
 python_gen_useflags() {
 	debug-print-function ${FUNCNAME} "${@}"

 	local impl pattern
 	local matches=()

 	for impl in "${PYTHON_COMPAT[@]}"; do
 		_python_impl_supported "${impl}" || continue

 		for pattern; do
 			if [[ ${impl} == ${pattern} ]]; then
 				matches+=( "python_single_target_${impl}" )
 				break
 			fi
 		done
 	done

 	echo "${matches[@]}"
 }

 # @FUNCTION: python_gen_cond_dep
 # @USAGE: <dependency> <pattern> [...]
 # @DESCRIPTION:
 # Output a list of <dependency>-ies made conditional to USE flags
 # of Python implementations which are both in PYTHON_COMPAT and match
 # any of the patterns passed as the remaining parameters.
 #
 # In order to enforce USE constraints on the packages, verbatim
 # '${PYTHON_USEDEP}' (quoted!) may be placed in the dependency
 # specification. It will get expanded within the function into a proper
 # USE dependency string.
 #
 # Example:
 # @CODE
 # PYTHON_COMPAT=( python{2_5,2_6,2_7} )
 # RDEPEND="$(python_gen_cond_dep \
 #   'dev-python/unittest2[${PYTHON_USEDEP}]' python{2_5,2_6})"
 # @CODE
 #
 # It will cause the variable to look like:
 # @CODE
 # RDEPEND="python_single_target_python2_5? (
 #     dev-python/unittest2[python_targets_python2_5(-)?,...] )
 #	python_single_target_python2_6? (
 #     dev-python/unittest2[python_targets_python2_6(-)?,...] )"
 # @CODE
 python_gen_cond_dep() {
 	debug-print-function ${FUNCNAME} "${@}"

 	local impl pattern
 	local matches=()

 	local dep=${1}
 	shift

 	for impl in "${PYTHON_COMPAT[@]}"; do
 		_python_impl_supported "${impl}" || continue

 		for pattern; do
 			if [[ ${impl} == ${pattern} ]]; then
 				# substitute ${PYTHON_USEDEP} if used
 				# (since python_gen_usedep() will not return ${PYTHON_USEDEP}
 				#  the code is run at most once)
 				if [[ ${dep} == *'${PYTHON_USEDEP}'* ]]; then
 					local PYTHON_USEDEP=$(python_gen_usedep "${@}")
 					dep=${dep//\$\{PYTHON_USEDEP\}/${PYTHON_USEDEP}}
 				fi

 				matches+=( "python_single_target_${impl}? ( ${dep} )" )
 				break
 			fi
 		done
 	done

 	echo "${matches[@]}"
 }

 # @FUNCTION: python_setup
 # @DESCRIPTION:
 # Determine what the selected Python implementation is and set
 # the Python build environment up for it.
 python_setup() {
 	debug-print-function ${FUNCNAME} "${@}"

 	_python_check_EAPI

 	unset EPYTHON

 	local impl impls=()
 	for impl in "${PYTHON_COMPAT[@]}"; do
 		_python_impl_supported "${impl}" || continue
 		impls+=( "${impl}" )
 	done

 	if [[ ${#impls[@]} -eq 1 ]]; then
 		if use "python_targets_${impls[0]}"; then
 			# Only one supported implementation, enable it explicitly
 			python_export "${impls[0]}" EPYTHON PYTHON
 			python_wrapper_setup
 		fi
 	else
 		for impl in "${impls[@]}"; do
 			if use "python_single_target_${impl}"; then
 				if [[ ${EPYTHON} ]]; then
 					eerror "Your PYTHON_SINGLE_TARGET setting lists more than a single Python"
 					eerror "implementation. Please set it to just one value. If you need"
 					eerror "to override the value for a single package, please use package.env"
 					eerror "or an equivalent solution (man 5 portage)."
 					echo
 					die "More than one implementation in PYTHON_SINGLE_TARGET."
 				fi

 				if ! use "python_targets_${impl}"; then
 					eerror "The implementation chosen as PYTHON_SINGLE_TARGET must be added"
 					eerror "to PYTHON_TARGETS as well. This is in order to ensure that"
 					eerror "dependencies are satisfied correctly. We're sorry"
 					eerror "for the inconvenience."
 					echo
 					die "Build target (${impl}) not in PYTHON_TARGETS."
 				fi

 				python_export "${impl}" EPYTHON PYTHON
 				python_wrapper_setup
 			fi
 		done
 	fi

 	if [[ ! ${EPYTHON} ]]; then
 		eerror "No Python implementation selected for the build. Please set"
 		if [[ ${#impls[@]} -eq 1 ]]; then
 			eerror "the PYTHON_TARGETS variable in your make.conf to include one"
 		else
 			eerror "the PYTHON_SINGLE_TARGET variable in your make.conf to one"
 		fi
 		eerror "of the following values:"
 		eerror
 		eerror "${impls[@]}"
 		echo
 		die "No supported Python implementation in PYTHON_SINGLE_TARGET/PYTHON_TARGETS."
 	fi
 }

 # @FUNCTION: python-single-r1_pkg_setup
 # @DESCRIPTION:
 # Runs python_setup.
 python-single-r1_pkg_setup() {
 	debug-print-function ${FUNCNAME} "${@}"

 	[[ ${MERGE_TYPE} != binary ]] && python_setup
 }

 _PYTHON_SINGLE_R1=1
 fi
	# Copyright 1999-2015 Gentoo Foundation
	# Distributed under the terms of the GNU General Public License v2
	# $Header: /var/cvsroot/gentoo-x86/eclass/python-single-r1.eclass,v 1.36 2015/02/20 17:57:22 mgorny Exp $

	# @ECLASS: python-single-r1
	# @MAINTAINER:
	# Python team <python@gentoo.org>
	# @AUTHOR:
	# Author: Michał Górny <mgorny@gentoo.org>
	# Based on work of: Krzysztof Pawlik <nelchael@gentoo.org>
	# @BLURB: An eclass for Python packages not installed for multiple implementations.
	# @DESCRIPTION:
	# An extension of the python-r1 eclass suite for packages which
	# don't support being installed for multiple Python implementations.
	# This mostly includes tools embedding Python.
	#
	# This eclass extends the IUSE and REQUIRED_USE set by python-r1
	# to request the PYTHON_SINGLE_TARGET when the inheriting ebuild
	# can be supported by more than one Python implementation. It also
	# replaces PYTHON_USEDEP and PYTHON_DEPS with a more suitable form.
	#
	# Please note that packages support multiple Python implementations
	# (using python-r1 eclass) can not depend on packages not supporting
	# them (using this eclass).
	#
	# Please note that python-single-r1 will always inherit python-utils-r1
	# as well. Thus, all the functions defined there can be used
	# in the packages using python-single-r1, and there is no need ever
	# to inherit both.
	#
	# For more information, please see the python-r1 Developer's Guide:
	# http://www.gentoo.org/proj/en/Python/python-r1/dev-guide.xml

	case "${EAPI:-0}" in
	0\|1\|2\|3)
	die "Unsupported EAPI=${EAPI:-0} (too old) for ${ECLASS}"
	;;
	4\|5)
	# EAPI=4 is required for USE default deps on USE_EXPAND flags
	;;
	*)
	die "Unsupported EAPI=${EAPI} (unknown) for ${ECLASS}"
	;;
	esac

	if [[ ! ${_PYTHON_SINGLE_R1} ]]; then

	if [[ ${_PYTHON_R1} ]]; then
	die 'python-single-r1.eclass can not be used with python-r1.eclass.'
	elif [[ ${_PYTHON_ANY_R1} ]]; then
	die 'python-single-r1.eclass can not be used with python-any-r1.eclass.'
	fi

	inherit python-utils-r1

	fi

	EXPORT_FUNCTIONS pkg_setup

	if [[ ! ${_PYTHON_SINGLE_R1} ]]; then

	# @ECLASS-VARIABLE: PYTHON_COMPAT
	# @REQUIRED
	# @DESCRIPTION:
	# This variable contains a list of Python implementations the package
	# supports. It must be set before the `inherit' call. It has to be
	# an array.
	#
	# Example:
	# @CODE
	# PYTHON_COMPAT=( python{2_5,2_6,2_7} )
	# @CODE
	if ! declare -p PYTHON_COMPAT &>/dev/null; then
	die 'PYTHON_COMPAT not declared.'
	fi

	# @ECLASS-VARIABLE: PYTHON_REQ_USE
	# @DEFAULT_UNSET
	# @DESCRIPTION:
	# The list of USEflags required to be enabled on the chosen Python
	# implementations, formed as a USE-dependency string. It should be valid
	# for all implementations in PYTHON_COMPAT, so it may be necessary to
	# use USE defaults.
	#
	# This should be set before calling `inherit'.
	#
	# Example:
	# @CODE
	# PYTHON_REQ_USE="gdbm,ncurses(-)?"
	# @CODE
	#
	# It will cause the Python dependencies to look like:
	# @CODE
	# python_single_target_pythonX_Y? ( dev-lang/python:X.Y[gdbm,ncurses(-)?] )
	# @CODE

	# @ECLASS-VARIABLE: PYTHON_DEPS
	# @DESCRIPTION:
	# This is an eclass-generated Python dependency string for all
	# implementations listed in PYTHON_COMPAT.
	#
	# The dependency string is conditional on PYTHON_SINGLE_TARGET.
	#
	# Example use:
	# @CODE
	# RDEPEND="${PYTHON_DEPS}
	# dev-foo/mydep"
	# DEPEND="${RDEPEND}"
	# @CODE
	#
	# Example value:
	# @CODE
	# dev-lang/python-exec:=
	# python_single_target_python2_6? ( dev-lang/python:2.6[gdbm] )
	# python_single_target_python2_7? ( dev-lang/python:2.7[gdbm] )
	# @CODE

	# @ECLASS-VARIABLE: PYTHON_USEDEP
	# @DESCRIPTION:
	# This is an eclass-generated USE-dependency string which can be used to
	# depend on another Python package being built for the same Python
	# implementations.
	#
	# The generate USE-flag list is compatible with packages using python-r1,
	# python-single-r1 and python-distutils-ng eclasses. It must not be used
	# on packages using python.eclass.
	#
	# Example use:
	# @CODE
	# RDEPEND="dev-python/foo[${PYTHON_USEDEP}]"
	# @CODE
	#
	# Example value:
	# @CODE
	# python_targets_python2_7(-)?,python_single_target_python2_7(+)?
	# @CODE

	# @ECLASS-VARIABLE: PYTHON_REQUIRED_USE
	# @DESCRIPTION:
	# This is an eclass-generated required-use expression which ensures the following
	# when more than one python implementation is possible:
	# 1. Exactly one PYTHON_SINGLE_TARGET value has been enabled.
	# 2. The selected PYTHON_SINGLE_TARGET value is enabled in PYTHON_TARGETS.
	#
	# This expression should be utilized in an ebuild by including it in
	# REQUIRED_USE, optionally behind a use flag.
	#
	# Example use:
	# @CODE
	# REQUIRED_USE="python? ( ${PYTHON_REQUIRED_USE} )"
	# @CODE
	#
	# Example value:
	# @CODE
	# python_single_target_python2_6? ( python_targets_python2_6 )
	# python_single_target_python2_7? ( python_targets_python2_7 )
	# ^^ ( python_single_target_python2_6 python_single_target_python2_7 )
	# @CODE

	_python_single_set_globals() {
	local impls=()
	local unimpls=()

	PYTHON_DEPS=
	local i PYTHON_PKG_DEP
	for i in "${_PYTHON_ALL_IMPLS[@]}"; do
	has "${i}" "${PYTHON_COMPAT[@]}" \
	&& impls+=( "${i}" ) \
	\|\| unimpls+=( "${i}" )
	done

	if [[ ${#impls[@]} -eq 0 ]]; then
	die "No supported implementation in PYTHON_COMPAT."
	fi

	local flags_mt=( "${impls[@]/#/python_targets_}" )
	local flags=( "${impls[@]/#/python_single_target_}" )
	local unflags=( "${unimpls[@]/#/-python_single_target_}" )

	local optflags=${flags_mt[@]/%/(-)?},${unflags[@]/%/(-)}

	IUSE="${flags_mt[*]}"

	if [[ ${#impls[@]} -eq 1 ]]; then
	# There is only one supported implementation; set IUSE and other
	# variables without PYTHON_SINGLE_TARGET.
	PYTHON_REQUIRED_USE="${flags_mt[*]}"
	python_export "${impls[0]}" PYTHON_PKG_DEP
	PYTHON_DEPS="${PYTHON_PKG_DEP} "
	# Force on the python_single_target_* flag for this impl, so
	# that any dependencies that inherit python-single-r1 and
	# happen to have multiple implementations will still need
	# to bound by the implementation used by this package.
	optflags+=,${flags[0]/%/(+)}
	else
	# Multiple supported implementations; honor PYTHON_SINGLE_TARGET.
	IUSE+=" ${flags[*]}"
	PYTHON_REQUIRED_USE="^^ ( ${flags[*]} )"
	# Ensure deps honor the same python_single_target_* flag as is set
	# on this package.
	optflags+=,${flags[@]/%/(+)?}

	for i in "${impls[@]}"; do
	# The chosen targets need to be in PYTHON_TARGETS as well.
	# This is in order to enforce correct dependencies on packages
	# supporting multiple implementations.
	PYTHON_REQUIRED_USE+=" python_single_target_${i}? ( python_targets_${i} )"

	python_export "${i}" PYTHON_PKG_DEP
	PYTHON_DEPS+="python_single_target_${i}? ( ${PYTHON_PKG_DEP} ) "
	done
	fi
	PYTHON_USEDEP=${optflags// /,}

	# 1) well, python-exec would suffice as an RDEP
	# but no point in making this overcomplex, BDEP doesn't hurt anyone
	# 2) python-exec should be built with all targets forced anyway
	# but if new targets were added, we may need to force a rebuild
	# 3) use whichever python-exec slot installed in EAPI 5. For EAPI 4,
	# just fix :2 since := deps are not supported.
	if [[ ${_PYTHON_WANT_PYTHON_EXEC2} == 0 ]]; then
	die "python-exec:0 is no longer supported, please fix your ebuild to work with python-exec:2"
	elif [[ ${EAPI} != 4 ]]; then
	PYTHON_DEPS+=">=dev-lang/python-exec-2:=[${PYTHON_USEDEP}]"
	else
	PYTHON_DEPS+="dev-lang/python-exec:2[${PYTHON_USEDEP}]"
	fi
	}
	_python_single_set_globals

	# @FUNCTION: python_gen_usedep
	# @USAGE: <pattern> [...]
	# @DESCRIPTION:
	# Output a USE dependency string for Python implementations which
	# are both in PYTHON_COMPAT and match any of the patterns passed
	# as parameters to the function.
	#
	# Remember to escape or quote the patterns to prevent shell filename
	# expansion.
	#
	# When all implementations are requested, please use ${PYTHON_USEDEP}
	# instead. Please also remember to set an appropriate REQUIRED_USE
	# to avoid ineffective USE flags.
	#
	# Example:
	# @CODE
	# PYTHON_COMPAT=( python{2_7,3_4} )
	# DEPEND="doc? ( dev-python/epydoc[$(python_gen_usedep 'python2*')] )"
	# @CODE
	#
	# It will cause the dependency to look like:
	# @CODE
	# DEPEND="doc? ( dev-python/epydoc[python_targets_python2_7(-)?,...] )"
	# @CODE
	python_gen_usedep() {
	debug-print-function ${FUNCNAME} "${@}"

	local impl pattern
	local matches=()

	for impl in "${PYTHON_COMPAT[@]}"; do
	_python_impl_supported "${impl}" \|\| continue

	for pattern; do
	if [[ ${impl} == ${pattern} ]]; then
	matches+=(
	"python_targets_${impl}(-)?"
	"python_single_target_${impl}(+)?"
	)
	break
	fi
	done
	done

	[[ ${matches[@]} ]] \|\| die "No supported implementations match python_gen_usedep patterns: ${@}"

	local out=${matches[@]}
	echo "${out// /,}"
	}

	# @FUNCTION: python_gen_useflags
	# @USAGE: <pattern> [...]
	# @DESCRIPTION:
	# Output a list of USE flags for Python implementations which
	# are both in PYTHON_COMPAT and match any of the patterns passed
	# as parameters to the function.
	#
	# Example:
	# @CODE
	# PYTHON_COMPAT=( python{2_7,3_4} )
	# REQUIRED_USE="doc? ( ^^ ( $(python_gen_useflags 'python2*') ) )"
	# @CODE
	#
	# It will cause the variable to look like:
	# @CODE
	# REQUIRED_USE="doc? ( ^^ ( python_single_target_python2_7 ) )"
	# @CODE
	python_gen_useflags() {
	debug-print-function ${FUNCNAME} "${@}"

	local impl pattern
	local matches=()

	for impl in "${PYTHON_COMPAT[@]}"; do
	_python_impl_supported "${impl}" \|\| continue

	for pattern; do
	if [[ ${impl} == ${pattern} ]]; then
	matches+=( "python_single_target_${impl}" )
	break
	fi
	done
	done

	echo "${matches[@]}"
	}

	# @FUNCTION: python_gen_cond_dep
	# @USAGE: <dependency> <pattern> [...]
	# @DESCRIPTION:
	# Output a list of <dependency>-ies made conditional to USE flags
	# of Python implementations which are both in PYTHON_COMPAT and match
	# any of the patterns passed as the remaining parameters.
	#
	# In order to enforce USE constraints on the packages, verbatim
	# '${PYTHON_USEDEP}' (quoted!) may be placed in the dependency
	# specification. It will get expanded within the function into a proper
	# USE dependency string.
	#
	# Example:
	# @CODE
	# PYTHON_COMPAT=( python{2_5,2_6,2_7} )
	# RDEPEND="$(python_gen_cond_dep \
	# 'dev-python/unittest2[${PYTHON_USEDEP}]' python{2_5,2_6})"
	# @CODE
	#
	# It will cause the variable to look like:
	# @CODE
	# RDEPEND="python_single_target_python2_5? (
	# dev-python/unittest2[python_targets_python2_5(-)?,...] )
	# python_single_target_python2_6? (
	# dev-python/unittest2[python_targets_python2_6(-)?,...] )"
	# @CODE
	python_gen_cond_dep() {
	debug-print-function ${FUNCNAME} "${@}"

	local impl pattern
	local matches=()

	local dep=${1}
	shift

	for impl in "${PYTHON_COMPAT[@]}"; do
	_python_impl_supported "${impl}" \|\| continue

	for pattern; do
	if [[ ${impl} == ${pattern} ]]; then
	# substitute ${PYTHON_USEDEP} if used
	# (since python_gen_usedep() will not return ${PYTHON_USEDEP}
	# the code is run at most once)
	if [[ ${dep} == '${PYTHON_USEDEP}' ]]; then
	local PYTHON_USEDEP=$(python_gen_usedep "${@}")
	dep=${dep//\$\{PYTHON_USEDEP\}/${PYTHON_USEDEP}}
	fi

	matches+=( "python_single_target_${impl}? ( ${dep} )" )
	break
	fi
	done
	done

	echo "${matches[@]}"
	}

	# @FUNCTION: python_setup
	# @DESCRIPTION:
	# Determine what the selected Python implementation is and set
	# the Python build environment up for it.
	python_setup() {
	debug-print-function ${FUNCNAME} "${@}"

	_python_check_EAPI

	unset EPYTHON

	local impl impls=()
	for impl in "${PYTHON_COMPAT[@]}"; do
	_python_impl_supported "${impl}" \|\| continue
	impls+=( "${impl}" )
	done

	if [[ ${#impls[@]} -eq 1 ]]; then
	if use "python_targets_${impls[0]}"; then
	# Only one supported implementation, enable it explicitly
	python_export "${impls[0]}" EPYTHON PYTHON
	python_wrapper_setup
	fi
	else
	for impl in "${impls[@]}"; do
	if use "python_single_target_${impl}"; then
	if [[ ${EPYTHON} ]]; then
	eerror "Your PYTHON_SINGLE_TARGET setting lists more than a single Python"
	eerror "implementation. Please set it to just one value. If you need"
	eerror "to override the value for a single package, please use package.env"
	eerror "or an equivalent solution (man 5 portage)."
	echo
	die "More than one implementation in PYTHON_SINGLE_TARGET."
	fi

	if ! use "python_targets_${impl}"; then
	eerror "The implementation chosen as PYTHON_SINGLE_TARGET must be added"
	eerror "to PYTHON_TARGETS as well. This is in order to ensure that"
	eerror "dependencies are satisfied correctly. We're sorry"
	eerror "for the inconvenience."
	echo
	die "Build target (${impl}) not in PYTHON_TARGETS."
	fi

	python_export "${impl}" EPYTHON PYTHON
	python_wrapper_setup
	fi
	done
	fi

	if [[ ! ${EPYTHON} ]]; then
	eerror "No Python implementation selected for the build. Please set"
	if [[ ${#impls[@]} -eq 1 ]]; then
	eerror "the PYTHON_TARGETS variable in your make.conf to include one"
	else
	eerror "the PYTHON_SINGLE_TARGET variable in your make.conf to one"
	fi
	eerror "of the following values:"
	eerror
	eerror "${impls[@]}"
	echo
	die "No supported Python implementation in PYTHON_SINGLE_TARGET/PYTHON_TARGETS."
	fi
	}

	# @FUNCTION: python-single-r1_pkg_setup
	# @DESCRIPTION:
	# Runs python_setup.
	python-single-r1_pkg_setup() {
	debug-print-function ${FUNCNAME} "${@}"

	[[ ${MERGE_TYPE} != binary ]] && python_setup
	}

	_PYTHON_SINGLE_R1=1
	fi