[gentoo-dev] RFC: python-distutils-ng.eclass - add a convenience variable for use deps

[Ian Stakenvicius]

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Hey all:

So one of the advantages of using python-distutils-ng.eclass for
building (and building against) python modules is that python module
dependencies can be guaranteed against the same python targets as what
you're building for, via the PYTHON_TARGETS use expansion.

Unfortunately, one of the drawbacks to this is that dependencies are
long and ugly.

Since in most cases, any python module in *DEPEND is going to have
python_targets_*? use deps for each implementation in $PYTHON_COMPAT,
a helper variable that can be substituted for this list would simplify
the ebuild.

The implementation in the patch below is probably not the best, but I
propose it as a starting point.


- --- python-distutils-ng.eclass  2012-06-18 10:53:33.000000000 -0400
+++ python-distutils-ng.eclass.new      2012-09-06 13:47:28.000000000
- -0400
@@ -59,6 +59,22 @@
 # Set to any value to disable automatic reinstallation of scripts in
 # bin directories. See python-distutils-ng_src_install function.

+# @ECLASS-VARIABLE: PTUD
+# @INTERNAL
+# @DESCRIPTION:
+# Provides the complete expansion of python_target_ use depedencies
+# from the content of $PYTHON_COMPAT ; it can be used as a shortform
+# to set or or append the use deps of complete python-module
+# dependencies, ie: RDEPEND="dev-python/foo[${PTUD}]"
+
+mysep=
+PTUD=
+for impl in ${PYTHON_COMPAT} ; do
+  PTUD+="${mysep}python_targets_${impl}?"
+  mysep=","
+done
+unset mysep
+
 EXPORT_FUNCTIONS src_prepare src_configure src_compile src_test [Snip!]

 case "${EAPI}" in
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