Tutorial: Move Step4-Ex1 to Step3-Ex2

During the training, we talk about INTERFACE libraries just before Step3
so it makes more sense to do the exercise related to them in Step3

7 files changed, 225 insertions, 200 deletions

diff --git a/Help/guide/tutorial/Adding Generator Expressions.rst b/Help/guide/tutorial/Adding Generator Expressions.rst
index aba9f7ad4d..3dab97ff04 100644
--- a/Help/guide/tutorial/Adding Generator Expressions.rst
+++ b/Help/guide/tutorial/Adding Generator Expressions.rst
@@ -27,168 +27,7 @@ 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.
 
-Exercise 1 - Setting the C++ Standard with Interface Libraries
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-Before we use :manual:`generator expressions <cmake-generator-expressions(7)>`
-let's refactor our existing code to use an ``INTERFACE`` library. We will
-use that library in the next step to demonstrate a common use for
-:manual:`generator expressions <cmake-generator-expressions(7)>`.
-
-Goal
-----
-
-Add an ``INTERFACE`` library target to specify the required C++ standard.
-
-Helpful Resources
------------------
-
-* :command:`add_library`
-* :command:`target_compile_features`
-* :command:`target_link_libraries`
-
-Files to Edit
--------------
-
-* ``CMakeLists.txt``
-* ``MathFunctions/CMakeLists.txt``
-
-Getting Started
----------------
-
-In this exercise, we will refactor our code to use an ``INTERFACE`` library to
-specify the C++ standard.
-
-The starting source code is provided in the ``Step4`` directory. In this
-exercise, complete ``TODO 1`` through ``TODO 3``.
-
-Start by editing the top level ``CMakeLists.txt`` file. Construct an
-``INTERFACE`` library target called ``tutorial_compiler_flags`` and
-specify ``cxx_std_11`` as a target compiler feature.
-
-Modify ``CMakeLists.txt`` and ``MathFunctions/CMakeLists.txt`` so that all
-targets have a :command:`target_link_libraries` call to
-``tutorial_compiler_flags``.
-
-Build and Run
--------------
-
-Make a new directory called ``Step4_build``, run the :manual:`cmake <cmake(1)>`
-executable or the :manual:`cmake-gui <cmake-gui(1)>` to configure the project
-and then build it with your chosen build tool or by using ``cmake --build .``
-from the build directory.
-
-Here's a refresher of what that looks like from the command line:
-
-.. code-block:: console
-
-  mkdir Step4_build
-  cd Step4_build
-  cmake ../Step4
-  cmake --build .
-
-Next, use the newly built ``Tutorial`` and verify that it is working as
-expected.
-
-Solution
---------
-
-Let's update our code from the previous step to use interface libraries
-to set our C++ requirements.
-
-To start, we need to remove the two :command:`set` calls on the variables
-:variable:`CMAKE_CXX_STANDARD` and :variable:`CMAKE_CXX_STANDARD_REQUIRED`.
-The specific lines to remove are as follows:
-
-.. literalinclude:: Step4/CMakeLists.txt
-  :caption: CMakeLists.txt
-  :name: CMakeLists.txt-CXX_STANDARD-variable-remove
-  :language: cmake
-  :start-after: # specify the C++ standard
-  :end-before: # TODO 6: Create helper variables
-
-Next, we need to create an interface library, ``tutorial_compiler_flags``. And
-then use :command:`target_compile_features` to add the compiler feature
-``cxx_std_11``.
-
-
-.. raw:: html
-
-  <details><summary>TODO 1: Click to show/hide answer</summary>
-
-.. literalinclude:: Step5/CMakeLists.txt
-  :caption: TODO 1: CMakeLists.txt
-  :name: CMakeLists.txt-cxx_std-feature
-  :language: cmake
-  :start-after: # specify the C++ standard
-  :end-before: # add compiler warning flags just
-
-.. raw:: html
-
-  </details>
-
-Finally, with our interface library set up, we need to link our
-executable ``Target``, our ``MathFunctions`` library, and our ``SqrtLibrary``
-library to our new
-``tutorial_compiler_flags`` library. Respectively, the code will look like
-this:
-
-.. raw:: html
-
-  <details><summary>TODO 2: Click to show/hide answer</summary>
-
-.. literalinclude:: Step5/CMakeLists.txt
-  :caption: TODO 2: CMakeLists.txt
-  :name: CMakeLists.txt-target_link_libraries-step4
-  :language: cmake
-  :start-after: add_executable(Tutorial tutorial.cxx)
-  :end-before: # add the binary tree to the search path for include file
-
-.. raw:: html
-
-  </details>
-
-this:
-
-.. raw:: html
-
-  <details><summary>TODO 3: Click to show/hide answer</summary>
-
-.. literalinclude:: Step5/MathFunctions/CMakeLists.txt
-  :caption: TODO 3: MathFunctions/CMakeLists.txt
-  :name: MathFunctions-CMakeLists.txt-target_link_libraries-step4
-  :language: cmake
-  :start-after: # link our compiler flags interface library
-  :end-before: target_link_libraries(MathFunctions
-
-.. raw:: html
-
-  </details>
-
-and this:
-
-.. raw:: html
-
-  <details><summary>TODO 4: Click to show/hide answer</summary>
-
-.. literalinclude:: Step5/MathFunctions/CMakeLists.txt
-  :caption: TODO 4: MathFunctions/CMakeLists.txt
-  :name: MathFunctions-SqrtLibrary-target_link_libraries-step4
-  :language: cmake
-  :start-after: target_link_libraries(SqrtLibrary
-  :end-before: endif()
-
-.. raw:: html
-
-  </details>
-
-
-With this, all of our code still requires C++ 11 to build. Notice
-though that with this method, it gives us the ability to be specific about
-which targets get specific requirements. In addition, we create a single
-source of truth in our interface library.
-
-Exercise 2 - Adding Compiler Warning Flags with Generator Expressions
+Exercise 1 - Adding Compiler Warning Flags with Generator Expressions
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 A common usage of
@@ -218,8 +57,8 @@ Files to Edit
 Getting Started
 ---------------
 
-Start with the resulting files from Exercise 1. Complete ``TODO 5`` through
-``TODO 8``.
+Open the file ``Step4/CMakeLists.txt`` and complete ``TODO 1`` through
+``TODO 4``.
 
 First, in the top level ``CMakeLists.txt`` file, we need to set the
 :command:`cmake_minimum_required` to ``3.15``. In this exercise we are going
@@ -233,12 +72,16 @@ given a language and a set of compiler ids.
 Build and Run
 -------------
 
-Since we have our build directory already configured from Exercise 1, simply
-rebuild our code by calling the following:
+Make a new directory called ``Step4_build``, run the :manual:`cmake <cmake(1)>`
+executable or the :manual:`cmake-gui <cmake-gui(1)>` to configure the project
+and then build it with your chosen build tool or by using ``cmake --build .``
+from the build directory.
 
 .. code-block:: console
 
+  mkdir Step4_build
   cd Step4_build
+  cmake ../Step4
   cmake --build .
 
 Solution
@@ -249,10 +92,10 @@ version ``3.15``:
 
 .. raw:: html
 
-  <details><summary>TODO 5: Click to show/hide answer</summary>
+  <details><summary>TODO 1: Click to show/hide answer</summary>
 
 .. literalinclude:: Step5/CMakeLists.txt
-  :caption: TODO 5: CMakeLists.txt
+  :caption: TODO 1: CMakeLists.txt
   :name: MathFunctions-CMakeLists.txt-minimum-required-step4
   :language: cmake
   :end-before: # set the project name and version
@@ -268,10 +111,10 @@ variables ``gcc_like_cxx`` and ``msvc_cxx`` as follows:
 
 .. raw:: html
 
-  <details><summary>TODO 6: Click to show/hide answer</summary>
+  <details><summary>TODO 2: Click to show/hide answer</summary>
 
 .. literalinclude:: Step5/CMakeLists.txt
-  :caption: TODO 6: CMakeLists.txt
+  :caption: TODO 2: CMakeLists.txt
   :name: CMakeLists.txt-compile_lang_and_id
   :language: cmake
   :start-after: # the BUILD_INTERFACE genex
@@ -289,10 +132,10 @@ interface library.
 
 .. raw:: html
 
-  <details><summary>TODO 7: Click to show/hide answer</summary>
+  <details><summary>TODO 3: Click to show/hide answer</summary>
 
 .. code-block:: cmake
-  :caption: TODO 7: CMakeLists.txt
+  :caption: TODO 3: CMakeLists.txt
   :name: CMakeLists.txt-compile_flags
 
   target_compile_options(tutorial_compiler_flags INTERFACE
@@ -311,10 +154,10 @@ condition. The resulting full code looks like the following:
 
 .. raw:: html
 
-  <details><summary>TODO 8: Click to show/hide answer</summary>
+  <details><summary>TODO 4: Click to show/hide answer</summary>
 
 .. literalinclude:: Step5/CMakeLists.txt
-  :caption: TODO 8: CMakeLists.txt
+  :caption: TODO 4: CMakeLists.txt
   :name: CMakeLists.txt-target_compile_options-genex
   :language: cmake
   :start-after: set(msvc_cxx "$<COMPILE_LANG_AND_ID:CXX,MSVC>")
diff --git a/Help/guide/tutorial/Adding Usage Requirements for a Library.rst b/Help/guide/tutorial/Adding Usage Requirements for a Library.rst
index 74b7496688..227306393e 100644
--- a/Help/guide/tutorial/Adding Usage Requirements for a Library.rst
+++ b/Help/guide/tutorial/Adding Usage Requirements for a Library.rst
@@ -100,7 +100,7 @@ follows:
   :name: MathFunctions/CMakeLists.txt-target_include_directories-INTERFACE
   :language: cmake
   :start-after: # to find MathFunctions.h
-  :end-before: option
+  :end-before: # should we use our own
 
 .. raw:: html
 
@@ -108,24 +108,26 @@ follows:
 
 Now that we've specified usage requirements for ``MathFunctions`` we can
 safely remove our uses of the ``EXTRA_INCLUDES`` variable from the top-level
-``CMakeLists.txt``, here:
+``CMakeLists.txt``.
+
+Remove this line:
 
 .. raw:: html
 
   <details><summary>TODO 2: Click to show/hide answer</summary>
 
-.. literalinclude:: Step4/CMakeLists.txt
+.. literalinclude:: Step3/CMakeLists.txt
   :caption: TODO 2: CMakeLists.txt
   :name: CMakeLists.txt-remove-EXTRA_INCLUDES
   :language: cmake
-  :start-after: # add the MathFunctions library
-  :end-before: # TODO 2: Link to tutorial_compiler_flags
+  :start-after: add_subdirectory(MathFunctions)
+  :end-before: # add the executable
 
 .. raw:: html
 
   </details>
 
-And here:
+And the lines:
 
 .. raw:: html
 
@@ -141,7 +143,181 @@ And here:
 
   </details>
 
+The remaining code looks like:
+
+.. raw:: html
+
+  <details><summary>Click to show/hide the resulting code</summary>
+
+.. literalinclude:: Step4/CMakeLists.txt
+  :caption: Remaining code after removing EXTRA_INCLUDES
+  :name: CMakeLists.txt-after-removing-EXTRA_INCLUDES
+  :language: cmake
+  :start-after: add_subdirectory(MathFunctions)
+
+.. raw:: html
+
+  </details>
+
+
 Notice that with this technique, the only thing our executable target does to
 use our library is call :command:`target_link_libraries` with the name
 of the library target. In larger projects, the classic method of specifying
 library dependencies manually becomes very complicated very quickly.
+
+Exercise 2 - Setting the C++ Standard with Interface Libraries
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Now that we have switched our code to a more modern approach, let's demonstrate
+a modern technique to set properties to multiple targets.
+
+Let's refactor our existing code to use an ``INTERFACE`` library. We will
+use that library in the next step to demonstrate a common use for
+:manual:`generator expressions <cmake-generator-expressions(7)>`.
+
+Goal
+----
+
+Add an ``INTERFACE`` library target to specify the required C++ standard.
+
+Helpful Resources
+-----------------
+
+* :command:`add_library`
+* :command:`target_compile_features`
+* :command:`target_link_libraries`
+
+Files to Edit
+-------------
+
+* ``CMakeLists.txt``
+* ``MathFunctions/CMakeLists.txt``
+
+Getting Started
+---------------
+
+In this exercise, we will refactor our code to use an ``INTERFACE`` library to
+specify the C++ standard.
+
+Start this exercise from what we left at the end of Step3 exercise 1. You will
+have to complete ``TODO 4`` through ``TODO 7``.
+
+Start by editing the top level ``CMakeLists.txt`` file. Construct an
+``INTERFACE`` library target called ``tutorial_compiler_flags`` and
+specify ``cxx_std_11`` as a target compiler feature.
+
+Modify ``CMakeLists.txt`` and ``MathFunctions/CMakeLists.txt`` so that all
+targets have a :command:`target_link_libraries` call to
+``tutorial_compiler_flags``.
+
+Build and Run
+-------------
+
+Since we have our build directory already configured from Exercise 1, simply
+rebuild our code by calling the following:
+
+.. code-block:: console
+
+  cd Step3_build
+  cmake --build .
+
+Next, use the newly built ``Tutorial`` and verify that it is working as
+expected.
+
+Solution
+--------
+
+Let's update our code from the previous step to use interface libraries
+to set our C++ requirements.
+
+To start, we need to remove the two :command:`set` calls on the variables
+:variable:`CMAKE_CXX_STANDARD` and :variable:`CMAKE_CXX_STANDARD_REQUIRED`.
+The specific lines to remove are as follows:
+
+.. literalinclude:: Step3/CMakeLists.txt
+  :caption: CMakeLists.txt
+  :name: CMakeLists.txt-CXX_STANDARD-variable-remove
+  :language: cmake
+  :start-after: # specify the C++ standard
+  :end-before: # configure a header file
+
+Next, we need to create an interface library, ``tutorial_compiler_flags``. And
+then use :command:`target_compile_features` to add the compiler feature
+``cxx_std_11``.
+
+
+.. raw:: html
+
+  <details><summary>TODO 4: Click to show/hide answer</summary>
+
+.. literalinclude:: Step4/CMakeLists.txt
+  :caption: TODO 4: CMakeLists.txt
+  :name: CMakeLists.txt-cxx_std-feature
+  :language: cmake
+  :start-after: # specify the C++ standard
+  :end-before: # TODO 2: Create helper
+
+.. raw:: html
+
+  </details>
+
+Finally, with our interface library set up, we need to link our
+executable ``Target``, our ``MathFunctions`` library, and our ``SqrtLibrary``
+library to our new
+``tutorial_compiler_flags`` library. Respectively, the code will look like
+this:
+
+.. raw:: html
+
+  <details><summary>TODO 5: Click to show/hide answer</summary>
+
+.. literalinclude:: Step4/CMakeLists.txt
+  :caption: TODO 5: CMakeLists.txt
+  :name: CMakeLists.txt-target_link_libraries-step4
+  :language: cmake
+  :start-after: add_executable(Tutorial tutorial.cxx)
+  :end-before: # add the binary tree to the search path for include file
+
+.. raw:: html
+
+  </details>
+
+this:
+
+.. raw:: html
+
+  <details><summary>TODO 6: Click to show/hide answer</summary>
+
+.. literalinclude:: Step4/MathFunctions/CMakeLists.txt
+  :caption: TODO 6: MathFunctions/CMakeLists.txt
+  :name: MathFunctions-CMakeLists.txt-target_link_libraries-step4
+  :language: cmake
+  :start-after: # link our compiler flags interface library
+  :end-before: target_link_libraries(MathFunctions
+
+.. raw:: html
+
+  </details>
+
+and this:
+
+.. raw:: html
+
+  <details><summary>TODO 7: Click to show/hide answer</summary>
+
+.. literalinclude:: Step4/MathFunctions/CMakeLists.txt
+  :caption: TODO 7: MathFunctions/CMakeLists.txt
+  :name: MathFunctions-SqrtLibrary-target_link_libraries-step4
+  :language: cmake
+  :start-after: target_link_libraries(SqrtLibrary
+  :end-before: endif()
+
+.. raw:: html
+
+  </details>
+
+
+With this, all of our code still requires C++ 11 to build. Notice
+though that with this method, it gives us the ability to be specific about
+which targets get specific requirements. In addition, we create a single
+source of truth in our interface library.
diff --git a/Help/guide/tutorial/Adding a Library.rst b/Help/guide/tutorial/Adding a Library.rst
index d606f305e8..694dfaf621 100644
--- a/Help/guide/tutorial/Adding a Library.rst
+++ b/Help/guide/tutorial/Adding a Library.rst
@@ -409,7 +409,7 @@ that has sources ``mysqrt.cxx``.
   :name: MathFunctions/CMakeLists.txt-add_library-SqrtLibrary
   :language: cmake
   :start-after: # library that just does sqrt
-  :end-before: target_link_libraries(MathFunctions
+  :end-before: # TODO 7: Link
 
 .. raw:: html
 
@@ -426,7 +426,8 @@ enabled.
   :caption: TODO 13 : MathFunctions/CMakeLists.txt
   :name: MathFunctions/CMakeLists.txt-target_link_libraries-SqrtLibrary
   :language: cmake
-  :lines: 16-18
+  :start-after: to tutorial_compiler_flags
+  :end-before: endif()
 
 .. raw:: html
 
diff --git a/Help/guide/tutorial/Step3/CMakeLists.txt b/Help/guide/tutorial/Step3/CMakeLists.txt
index f051826a7d..ac3e9f1ed7 100644
--- a/Help/guide/tutorial/Step3/CMakeLists.txt
+++ b/Help/guide/tutorial/Step3/CMakeLists.txt
@@ -3,6 +3,12 @@ cmake_minimum_required(VERSION 3.10)
 # set the project name and version
 project(Tutorial VERSION 1.0)
 
+# TODO 4: Replace the following code by:
+# * Creating an interface library called tutorial_compiler_flags
+#   Hint: use add_library() with the INTERFACE signature
+# * Add compiler feature cxx_std_11 to tutorial_compiler_flags
+#   Hint: Use target_compile_features()
+
 # specify the C++ standard
 set(CMAKE_CXX_STANDARD 11)
 set(CMAKE_CXX_STANDARD_REQUIRED True)
@@ -20,6 +26,8 @@ list(APPEND EXTRA_INCLUDES "${PROJECT_SOURCE_DIR}/MathFunctions")
 # add the executable
 add_executable(Tutorial tutorial.cxx)
 
+# TODO 5: Link Tutorial to tutorial_compiler_flags
+
 target_link_libraries(Tutorial PUBLIC MathFunctions)
 
 # TODO 3: Remove use of EXTRA_INCLUDES
diff --git a/Help/guide/tutorial/Step3/MathFunctions/CMakeLists.txt b/Help/guide/tutorial/Step3/MathFunctions/CMakeLists.txt
index 6f86ffef5b..0ffb9e1f5b 100644
--- a/Help/guide/tutorial/Step3/MathFunctions/CMakeLists.txt
+++ b/Help/guide/tutorial/Step3/MathFunctions/CMakeLists.txt
@@ -14,5 +14,9 @@ if (USE_MYMATH)
               mysqrt.cxx
               )
 
+  # TODO 7: Link SqrtLibrary to tutorial_compiler_flags
+
   target_link_libraries(MathFunctions PUBLIC SqrtLibrary)
 endif()
+
+# TODO 6: Link MathFunctions to tutorial_compiler_flags
diff --git a/Help/guide/tutorial/Step4/CMakeLists.txt b/Help/guide/tutorial/Step4/CMakeLists.txt
index 7531fb41ab..fba97669b4 100644
--- a/Help/guide/tutorial/Step4/CMakeLists.txt
+++ b/Help/guide/tutorial/Step4/CMakeLists.txt
@@ -1,33 +1,27 @@
-# TODO 5: Update the minimum required version to 3.15
+# TODO 1: Update the minimum required version to 3.15
 
 cmake_minimum_required(VERSION 3.10)
 
 # set the project name and version
 project(Tutorial VERSION 1.0)
 
-# TODO 1: Replace the following code by:
-# * Creating an interface library called tutorial_compiler_flags
-#   Hint: use add_library() with the INTERFACE signature
-# * Add compiler feature cxx_std_11 to tutorial_compiler_flags
-#   Hint: Use target_compile_features()
-
 # specify the C++ standard
-set(CMAKE_CXX_STANDARD 11)
-set(CMAKE_CXX_STANDARD_REQUIRED True)
+add_library(tutorial_compiler_flags INTERFACE)
+target_compile_features(tutorial_compiler_flags INTERFACE cxx_std_11)
 
-# TODO 6: Create helper variables to determine which compiler we are using:
+# TODO 2: Create helper variables to determine which compiler we are using:
 # * Create a new variable gcc_like_cxx that is true if we are using CXX and
 #   any of the following compilers: ARMClang, AppleClang, Clang, GNU, LCC
 # * Create a new variable msvc_cxx that is true if we are using CXX and MSVC
 # Hint: Use set() and COMPILE_LANG_AND_ID
 
-# TODO 7: Add warning flag compile options to the interface library
+# TODO 3: Add warning flag compile options to the interface library
 # tutorial_compiler_flags.
 # * For gcc_like_cxx, add flags -Wall;-Wextra;-Wshadow;-Wformat=2;-Wunused
 # * For msvc_cxx, add flags -W3
 # Hint: Use target_compile_options()
 
-# TODO 8: With nested generator expressions, only use the flags for the
+# TODO 4: With nested generator expressions, only use the flags for the
 # build-tree
 # Hint: Use BUILD_INTERFACE
 
@@ -41,9 +35,7 @@ add_subdirectory(MathFunctions)
 # add the executable
 add_executable(Tutorial tutorial.cxx)
 
-# TODO 2: Link to tutorial_compiler_flags
-
-target_link_libraries(Tutorial PUBLIC MathFunctions)
+target_link_libraries(Tutorial PUBLIC MathFunctions tutorial_compiler_flags)
 
 # add the binary tree to the search path for include files
 # so that we will find TutorialConfig.h
diff --git a/Help/guide/tutorial/Step4/MathFunctions/CMakeLists.txt b/Help/guide/tutorial/Step4/MathFunctions/CMakeLists.txt
index ffab4f0a80..48561eb23b 100644
--- a/Help/guide/tutorial/Step4/MathFunctions/CMakeLists.txt
+++ b/Help/guide/tutorial/Step4/MathFunctions/CMakeLists.txt
@@ -17,9 +17,10 @@ if (USE_MYMATH)
               mysqrt.cxx
               )
 
-  # TODO 4: Link to tutorial_compiler_flags
-
+  # link our compiler flags interface library
+  target_link_libraries(SqrtLibrary PUBLIC tutorial_compiler_flags)
   target_link_libraries(MathFunctions PUBLIC SqrtLibrary)
 endif()
 
-# TODO 3: Link to tutorial_compiler_flags
+# link our compiler flags interface library
+target_link_libraries(MathFunctions PUBLIC tutorial_compiler_flags)