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Diffstat (limited to 'README.rst')
| -rw-r--r-- | README.rst | 18 |
1 files changed, 15 insertions, 3 deletions
@@ -18,6 +18,14 @@ should be relatively easy, if needed. The `Zephyr <https://www.zephyrproject.org/>`_ project uses Kconfiglib exclusively, with lots of small helper scripts in other projects. +Kconfiglib implements the recently added `Kconfig preprocessor +<https://github.com/torvalds/linux/blob/master/Documentation/kbuild/kconfig-macro-language.txt>`_. +For backwards compatibility, environment variables can be referenced both as +``$(FOO)`` (the new syntax) and as ``$FOO`` (the old syntax). Support for the +old syntax might be removed in the future (the major version would be increased +at the same time). Using the old syntax with an undefined environment variable +keeps the string as is. + Installation ------------ @@ -193,10 +201,14 @@ The following Kconfig extensions are available: - Environment variables are expanded directly in e.g. ``source`` and ``mainmenu`` statements, meaning ``option env`` symbols are redundant. + + This is the standard behavior with the new `Kconfig preprocessor + <https://github.com/torvalds/linux/blob/master/Documentation/kbuild/kconfig-macro-language.txt>`_, + which Kconfiglib implements. - ``option env`` symbols are still supported for compatibility, - with the caveat that they must have the same name as the environment - variables they reference. A warning is printed if the names differ. + ``option env`` symbols are supported for backwards compatibility, with the + caveat that they must have the same name as the environment variables they + reference. A warning is printed if the names differ. Other features -------------- |