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+Step 10: Adding Generator Expressions
+=====================================
+
+:manual:`Generator expressions <cmake-generator-expressions(7)>` are evaluated
+during build system generation to produce information specific to each build
+configuration.
+
+:manual:`Generator expressions <cmake-generator-expressions(7)>` are allowed in
+the context of many target properties, such as :prop_tgt:`LINK_LIBRARIES`,
+:prop_tgt:`INCLUDE_DIRECTORIES`, :prop_tgt:`COMPILE_DEFINITIONS` and others.
+They may also be used when using commands to populate those properties, such as
+:command:`target_link_libraries`, :command:`target_include_directories`,
+:command:`target_compile_definitions` and others.
+
+:manual:`Generator expressions <cmake-generator-expressions(7)>`  may be used
+to enable conditional linking, conditional definitions used when compiling,
+conditional include directories and more. The conditions may be based on the
+build configuration, target properties, platform information or any other
+queryable information.
+
+There are different types of
+:manual:`generator expressions <cmake-generator-expressions(7)>` including
+Logical, Informational, and Output expressions.
+
+Logical expressions are used to create conditional output. The basic
+expressions are the 0 and 1 expressions. A ``$<0:...>`` results in the empty
+string, and ``<1:...>`` results in the content of "...".  They can also be
+nested.
+
+A common usage of
+:manual:`generator expressions <cmake-generator-expressions(7)>` is to
+conditionally add compiler flags, such as those for language levels or
+warnings. A nice pattern is to associate this information to an ``INTERFACE``
+target allowing this information to propagate. Let's start by constructing an
+``INTERFACE`` target and specifying the required C++ standard level of ``11``
+instead of using :variable:`CMAKE_CXX_STANDARD`.
+
+So the following code:
+
+.. literalinclude:: Step10/CMakeLists.txt
+  :language: cmake
+  :start-after: project(Tutorial VERSION 1.0)
+  :end-before: # control where the static and shared libraries are built so that on windows
+
+Would be replaced with:
+
+.. literalinclude:: Step11/CMakeLists.txt
+  :language: cmake
+  :start-after: project(Tutorial VERSION 1.0)
+  :end-before: # add compiler warning flags just when building this project via
+
+
+Next we add the desired compiler warning flags that we want for our project. As
+warning flags vary based on the compiler we use the ``COMPILE_LANG_AND_ID``
+generator expression to control which flags to apply given a language and a set
+of compiler ids as seen below:
+
+.. literalinclude:: Step11/CMakeLists.txt
+  :language: cmake
+  :start-after: # the BUILD_INTERFACE genex
+  :end-before: # control where the static and shared libraries are built so that on windows
+
+Looking at this we see that the warning flags are encapsulated inside a
+``BUILD_INTERFACE`` condition. This is done so that consumers of our installed
+project will not inherit our warning flags.
+
+
+**Exercise**: Modify ``MathFunctions/CMakeLists.txt`` so that all targets have
+a :command:`target_link_libraries` call to ``tutorial_compiler_flags``.