CMakePackageConfigHelpers: restructure documentation and document commands

1 files changed, 125 insertions, 120 deletions

diff --git a/Modules/CMakePackageConfigHelpers.cmake b/Modules/CMakePackageConfigHelpers.cmake
index 318382e..1e47f15 100644
--- a/Modules/CMakePackageConfigHelpers.cmake
+++ b/Modules/CMakePackageConfigHelpers.cmake
@@ -2,29 +2,35 @@
 # CMakePackageConfigHelpers
 # -------------------------
 #
-# CONFIGURE_PACKAGE_CONFIG_FILE(), WRITE_BASIC_PACKAGE_VERSION_FILE()
+# Helpers functions for creating config files that can be included by other
+# projects to find and use a package.
 #
+# Adds the :command:`configure_package_config_file()` and
+# :command:`write_basic_package_version_file()` commands.
 #
+# Generating a Package Configuration File
+# ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 #
-# ::
+# .. command:: configure_package_config_file
 #
-#     CONFIGURE_PACKAGE_CONFIG_FILE(<input> <output> INSTALL_DESTINATION <path>
+#  Create a config file for a project::
+#
+#     configure_package_config_file(<input> <output> INSTALL_DESTINATION <path>
 #                                                    [PATH_VARS <var1> <var2> ... <varN>]
 #                                                    [NO_SET_AND_CHECK_MACRO]
 #                                                    [NO_CHECK_REQUIRED_COMPONENTS_MACRO])
 #
 #
+# ``configure_package_config_file()`` should be used instead of the plain
+# :command:`configure_file()` command when creating the ``<Name>Config.cmake``
+# or ``<Name>-config.cmake`` file for installing a project or library.  It helps
+# making the resulting package relocatable by avoiding hardcoded paths in the
+# installed ``Config.cmake`` file.
 #
-# CONFIGURE_PACKAGE_CONFIG_FILE() should be used instead of the plain
-# configure_file() command when creating the <Name>Config.cmake or
-# <Name>-config.cmake file for installing a project or library.  It
-# helps making the resulting package relocatable by avoiding hardcoded
-# paths in the installed Config.cmake file.
-#
-# In a FooConfig.cmake file there may be code like this to make the
-# install destinations know to the using project:
+# In a ``FooConfig.cmake`` file there may be code like this to make the install
+# destinations know to the using project:
 #
-# ::
+# .. code-block:: cmake
 #
 #    set(FOO_INCLUDE_DIR   "@CMAKE_INSTALL_FULL_INCLUDEDIR@" )
 #    set(FOO_DATA_DIR   "@CMAKE_INSTALL_PREFIX@/@RELATIVE_DATA_INSTALL_DIR@" )
@@ -32,121 +38,126 @@
 #    ...logic to determine installedPrefix from the own location...
 #    set(FOO_CONFIG_DIR  "${installedPrefix}/@CONFIG_INSTALL_DIR@" )
 #
-# All 4 options shown above are not sufficient, since the first 3
-# hardcode the absolute directory locations, and the 4th case works only
-# if the logic to determine the installedPrefix is correct, and if
-# CONFIG_INSTALL_DIR contains a relative path, which in general cannot
-# be guaranteed.  This has the effect that the resulting FooConfig.cmake
-# file would work poorly under Windows and OSX, where users are used to
-# choose the install location of a binary package at install time,
-# independent from how CMAKE_INSTALL_PREFIX was set at build/cmake time.
-#
-# Using CONFIGURE_PACKAGE_CONFIG_FILE() helps.  If used correctly, it
-# makes the resulting FooConfig.cmake file relocatable.  Usage:
+# All 4 options shown above are not sufficient, since the first 3 hardcode the
+# absolute directory locations, and the 4th case works only if the logic to
+# determine the ``installedPrefix`` is correct, and if ``CONFIG_INSTALL_DIR``
+# contains a relative path, which in general cannot be guaranteed.  This has the
+# effect that the resulting ``FooConfig.cmake`` file would work poorly under
+# Windows and OSX, where users are used to choose the install location of a
+# binary package at install time, independent from how
+# :variable:`CMAKE_INSTALL_PREFIX` was set at build/cmake time.
 #
-# ::
+# Using ``configure_package_config_file`` helps.  If used correctly, it makes
+# the resulting ``FooConfig.cmake`` file relocatable.  Usage:
 #
-#    1. write a FooConfig.cmake.in file as you are used to
-#    2. insert a line containing only the string "@PACKAGE_INIT@"
-#    3. instead of set(FOO_DIR "@SOME_INSTALL_DIR@"), use set(FOO_DIR "@PACKAGE_SOME_INSTALL_DIR@")
-#       (this must be after the @PACKAGE_INIT@ line)
-#    4. instead of using the normal configure_file(), use CONFIGURE_PACKAGE_CONFIG_FILE()
+#    1. write a ``FooConfig.cmake.in`` file as you are used to
+#    2. insert a line containing only the string ``@PACKAGE_INIT@``
+#    3. instead of ``set(FOO_DIR "@SOME_INSTALL_DIR@")``, use
+#       ``set(FOO_DIR "@PACKAGE_SOME_INSTALL_DIR@")`` (this must be after the
+#       ``@PACKAGE_INIT@`` line)
+#    4. instead of using the normal :command:`configure_file()`, use
+#       ``configure_package_config_file()``
 #
 #
 #
-# The <input> and <output> arguments are the input and output file, the
-# same way as in configure_file().
+# The ``<input>`` and ``<output>`` arguments are the input and output file, the
+# same way as in :command:`configure_file()`.
 #
-# The <path> given to INSTALL_DESTINATION must be the destination where
-# the FooConfig.cmake file will be installed to.  This can either be a
+# The ``<path>`` given to ``INSTALL_DESTINATION`` must be the destination where
+# the ``FooConfig.cmake`` file will be installed to.  This can either be a
 # relative or absolute path, both work.
 #
-# The variables <var1> to <varN> given as PATH_VARS are the variables
-# which contain install destinations.  For each of them the macro will
-# create a helper variable PACKAGE_<var...>.  These helper variables
-# must be used in the FooConfig.cmake.in file for setting the installed
-# location.  They are calculated by CONFIGURE_PACKAGE_CONFIG_FILE() so
-# that they are always relative to the installed location of the
-# package.  This works both for relative and also for absolute
-# locations.  For absolute locations it works only if the absolute
-# location is a subdirectory of CMAKE_INSTALL_PREFIX.
-#
-# By default configure_package_config_file() also generates two helper
-# macros, set_and_check() and check_required_components() into the
-# FooConfig.cmake file.
-#
-# set_and_check() should be used instead of the normal set() command for
-# setting directories and file locations.  Additionally to setting the
-# variable it also checks that the referenced file or directory actually
-# exists and fails with a FATAL_ERROR otherwise.  This makes sure that
-# the created FooConfig.cmake file does not contain wrong references.
-# When using the NO_SET_AND_CHECK_MACRO, this macro is not generated
-# into the FooConfig.cmake file.
-#
-# check_required_components(<package_name>) should be called at the end
-# of the FooConfig.cmake file if the package supports components.  This
-# macro checks whether all requested, non-optional components have been
-# found, and if this is not the case, sets the Foo_FOUND variable to
-# FALSE, so that the package is considered to be not found.  It does
-# that by testing the Foo_<Component>_FOUND variables for all requested
-# required components.  When using the NO_CHECK_REQUIRED_COMPONENTS
-# option, this macro is not generated into the FooConfig.cmake file.
+# The variables ``<var1>`` to ``<varN>`` given as ``PATH_VARS`` are the
+# variables which contain install destinations.  For each of them the macro will
+# create a helper variable ``PACKAGE_<var...>``.  These helper variables must be
+# used in the ``FooConfig.cmake.in`` file for setting the installed location.
+# They are calculated by ``configure_package_config_file`` so that they are
+# always relative to the installed location of the package.  This works both for
+# relative and also for absolute locations.  For absolute locations it works
+# only if the absolute location is a subdirectory of
+# :variable:`CMAKE_INSTALL_PREFIX`.
+#
+# By default ``configure_package_config_file`` also generates two helper macros,
+# ``set_and_check()`` and ``check_required_components()`` into the
+# ``FooConfig.cmake`` file.
+#
+# ``set_and_check()`` should be used instead of the normal ``set()`` command for
+# setting directories and file locations.  Additionally to setting the variable
+# it also checks that the referenced file or directory actually exists and fails
+# with a ``FATAL_ERROR`` otherwise.  This makes sure that the created
+# ``FooConfig.cmake`` file does not contain wrong references.
+# When using the ``NO_SET_AND_CHECK_MACRO``, this macro is not generated
+# into the ``FooConfig.cmake`` file.
+#
+# ``check_required_components(<package_name>)`` should be called at the end of
+# the ``FooConfig.cmake`` file if the package supports components.  This macro
+# checks whether all requested, non-optional components have been found, and if
+# this is not the case, sets the ``Foo_FOUND`` variable to ``FALSE``, so that
+# the package is considered to be not found.  It does that by testing the
+# ``Foo_<Component>_FOUND`` variables for all requested required components.
+# When using the ``NO_CHECK_REQUIRED_COMPONENTS_MACRO`` option, this macro is
+# not generated into the ``FooConfig.cmake`` file.
 #
 # For an example see below the documentation for
-# WRITE_BASIC_PACKAGE_VERSION_FILE().
-#
-#
-#
-# ::
-#
-#   WRITE_BASIC_PACKAGE_VERSION_FILE( filename [VERSION major.minor.patch] COMPATIBILITY (AnyNewerVersion|SameMajorVersion|ExactVersion) )
-#
-#
-#
-# Writes a file for use as <package>ConfigVersion.cmake file to
-# <filename>.  See the documentation of find_package() for details on
-# this.
-#
-# ::
-#
-#     filename is the output filename, it should be in the build tree.
-#     major.minor.patch is the version number of the project to be installed
-#
-# If no ``VERSION`` is given, the :variable:`PROJECT_VERSION` variable
-# is used.  If this hasn't been set, it errors out.
-#
-# The COMPATIBILITY mode AnyNewerVersion means that the installed
-# package version will be considered compatible if it is newer or
-# exactly the same as the requested version.  This mode should be used
-# for packages which are fully backward compatible, also across major
-# versions.  If SameMajorVersion is used instead, then the behaviour
-# differs from AnyNewerVersion in that the major version number must be
-# the same as requested, e.g.  version 2.0 will not be considered
-# compatible if 1.0 is requested.  This mode should be used for packages
-# which guarantee backward compatibility within the same major version.
-# If ExactVersion is used, then the package is only considered
-# compatible if the requested version matches exactly its own version
-# number (not considering the tweak version).  For example, version
-# 1.2.3 of a package is only considered compatible to requested version
-# 1.2.3.  This mode is for packages without compatibility guarantees.
-# If your project has more elaborated version matching rules, you will
-# need to write your own custom ConfigVersion.cmake file instead of
-# using this macro.
-#
-# Internally, this macro executes configure_file() to create the
-# resulting version file.  Depending on the COMPATIBLITY, either the
-# file BasicConfigVersion-SameMajorVersion.cmake.in or
-# BasicConfigVersion-AnyNewerVersion.cmake.in is used.  Please note that
+# :command:`write_basic_package_version_file()`.
+#
+# Generating a Package Version File
+# ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+#
+# .. command:: write_basic_package_version_file
+#
+#  Create a version file for a project::
+#
+#     write_basic_package_version_file(<filename>
+#                                      [VERSION <major.minor.patch>]
+#                                      COMPATIBILITY <AnyNewerVersion|SameMajorVersion|ExactVersion> )
+#
+#
+# Writes a file for use as ``<package>ConfigVersion.cmake`` file to
+# ``<filename>``.  See the documentation of :command:`find_package()` for
+# details on this.
+#
+# ``<filename>`` is the output filename, it should be in the build tree.
+# ``<major.minor.patch>`` is the version number of the project to be installed.
+#
+# If no ``VERSION`` is given, the :variable:`PROJECT_VERSION` variable is used.
+# If this hasn't been set, it errors out.
+#
+# The ``COMPATIBILITY`` mode ``AnyNewerVersion`` means that the installed
+# package version will be considered compatible if it is newer or exactly the
+# same as the requested version.  This mode should be used for packages which
+# are fully backward compatible, also across major versions.
+# If ``SameMajorVersion`` is used instead, then the behaviour differs from
+# ``AnyNewerVersion`` in that the major version number must be the same as
+# requested, e.g.  version 2.0 will not be considered compatible if 1.0 is
+# requested.  This mode should be used for packages which guarantee backward
+# compatibility within the same major version.
+# If ``ExactVersion`` is used, then the package is only considered compatible if
+# the requested version matches exactly its own version number (not considering
+# the tweak version).  For example, version 1.2.3 of a package is only
+# considered compatible to requested version 1.2.3.  This mode is for packages
+# without compatibility guarantees.
+# If your project has more elaborated version matching rules, you will need to
+# write your own custom ``ConfigVersion.cmake`` file instead of using this
+# macro.
+#
+# Internally, this macro executes :command:`configure_file()` to create the
+# resulting version file.  Depending on the ``COMPATIBLITY``, either the file
+# ``BasicConfigVersion-SameMajorVersion.cmake.in`` or
+# ``BasicConfigVersion-AnyNewerVersion.cmake.in`` is used.  Please note that
 # these two files are internal to CMake and you should not call
-# configure_file() on them yourself, but they can be used as starting
-# point to create more sophisticted custom ConfigVersion.cmake files.
+# :command:`configure_file()` on them yourself, but they can be used as starting
+# point to create more sophisticted custom ``ConfigVersion.cmake`` files.
 #
+# Example Generating Package Files
+# ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 #
+# Example using both :command:`configure_package_config_file` and
+# ``write_basic_package_version_file()``:
 #
-# Example using both configure_package_config_file() and
-# write_basic_package_version_file(): CMakeLists.txt:
+# ``CMakeLists.txt``:
 #
-# ::
+# .. code-block:: cmake
 #
 #    set(INCLUDE_INSTALL_DIR include/ ... CACHE )
 #    set(LIB_INSTALL_DIR lib/ ... CACHE )
@@ -162,11 +173,9 @@
 #    install(FILES ${CMAKE_CURRENT_BINARY_DIR}/FooConfig.cmake ${CMAKE_CURRENT_BINARY_DIR}/FooConfigVersion.cmake
 #            DESTINATION ${LIB_INSTALL_DIR}/Foo/cmake )
 #
+# ``FooConfig.cmake.in``:
 #
-#
-# With a FooConfig.cmake.in:
-#
-# ::
+# .. code-block:: cmake
 #
 #    set(FOO_VERSION x.y.z)
 #    ...
@@ -175,10 +184,6 @@
 #    set_and_check(FOO_INCLUDE_DIR "@PACKAGE_INCLUDE_INSTALL_DIR@")
 #    set_and_check(FOO_SYSCONFIG_DIR "@PACKAGE_SYSCONFIG_INSTALL_DIR@")
 #
-#
-#
-# ::
-#
 #    check_required_components(Foo)