Help: Populate tutorial guide text

Migrate tutorial text from individual `directions.txt` files to the main
tutorial document.  Add some comments to source code to provide anchors
for inclusion.

3 files changed, 3 insertions, 102 deletions

diff --git a/Help/guide/tutorial/Step2/CMakeLists.txt b/Help/guide/tutorial/Step2/CMakeLists.txt
index 8e50e7c..1f43b2b 100644
--- a/Help/guide/tutorial/Step2/CMakeLists.txt
+++ b/Help/guide/tutorial/Step2/CMakeLists.txt
@@ -2,7 +2,8 @@ cmake_minimum_required(VERSION 3.3)
 project(Tutorial)
 
 set(CMAKE_CXX_STANDARD 14)
-# the version number.
+
+# set the version number
 set(Tutorial_VERSION_MAJOR 1)
 set(Tutorial_VERSION_MINOR 0)
 
diff --git a/Help/guide/tutorial/Step2/directions.txt b/Help/guide/tutorial/Step2/directions.txt
deleted file mode 100644
index 48de7a2..0000000
--- a/Help/guide/tutorial/Step2/directions.txt
+++ /dev/null
@@ -1,101 +0,0 @@
-# Adding a Library #
-
-Now we will add a library to our project. This library will contain our own
-implementation for computing the square root of a number. The executable can
-then use this library instead of the standard square root function provided by
-the compiler.
-
-For this tutorial we will put the library into a subdirectory
-called MathFunctions. It will have the following one line CMakeLists file:
-
-  add_library(MathFunctions mysqrt.cxx)
-
-The source file mysqrt.cxx has one function called mysqrt that provides similar
-functionality to the compiler’s sqrt function. To make use of the new library
-we add an add_subdirectory call in the top-level CMakeLists file so that the
-library will get built. We add the new library to the executable, and add the
-MathFunctions as an include directory so that mqsqrt.h header file can be
-found. The last few lines of the top-level CMakeLists file now look like:
-
-
-  add_subdirectory(MathFunctions)
-
-  #add the executable
-  add_executable(Tutorial tutorial.cxx)
-
-  target_link_libraries(Tutorial ${EXTRA_LIBS})
-
-
-Now let us make the MathFunctions library optional. While for the tutorial
-there really isn’t any need to do so, but with larger projects this is a common
-occurrence. The first step is to add an option to the top-level CMakeLists file.
-
-  option (USE_MYMATH
-          "Use tutorial provided math implementation" ON)
-
-This will show up in CMake GUI and ccmake with a default value of ON that can
-be changed by the user. This setting will be stored so that the user does not
-need to set the value each time they run CMake on this build directory.
-
-The next change is to make building and linking the MathFunctions library
-conditional. To do this we change the top-level CMakeLists file to look like
-the following:
-
-  cmake_minimum_required(VERSION 3.3)
-  project(Tutorial)
-
-  set(CMAKE_CXX_STANDARD 14)
-
-  # the version number.
-  set(Tutorial_VERSION_MAJOR 1)
-  set(Tutorial_VERSION_MINOR 0)
-
-  # configure a header file to pass some of the CMake settings
-  # to the source code
-  configure_file(
-    "${PROJECT_SOURCE_DIR}/TutorialConfig.h.in"
-    "${PROJECT_BINARY_DIR}/TutorialConfig.h"
-    )
-
-  # should we use our own math functions
-  option(USE_MYMATH "Use tutorial provided math implementation" ON)
-
-  # add the MathFunctions library?
-  if(USE_MYMATH)
-    add_subdirectory(MathFunctions)
-    list(APPEND EXTRA_LIBS MathFunctions)
-    list(APPEND EXTRA_INCLUDES "${PROJECT_SOURCE_DIR}/MathFunctions")
-  endif(USE_MYMATH)
-
-  # add the executable
-  add_executable(Tutorial tutorial.cxx)
-
-  target_link_libraries(Tutorial ${EXTRA_LIBS})
-
-  # add the binary tree to the search path for include files
-  # so that we will find TutorialConfig.h
-  target_include_directories(Tutorial PUBLIC
-                             "${PROJECT_BINARY_DIR}"
-                             ${EXTRA_INCLUDES}
-                             )
-
-Note the use of the variables EXTRA_LIBS, and EXTRA_INCLUDES to collect
-up any optional libraries to later be linked into the executable. This is a
-classic approach when dealing with many optional components, we will cover the
-modern approach in the next step. For now the corresponding changes to the
-source code are fairly straightforward and leave us with:
-
-  #ifdef USE_MYMATH
-    double outputValue = mysqrt(inputValue);
-  #else
-    double outputValue = sqrt(inputValue);
-  #endif
-
-Since the source code now requires USE_MYMATH we can add it to the
-TutorialConfig.h.in. Simply add the following line:
-  #cmakedefine USE_MYMATH
-
-Run cmake or cmake-gui to configure the project and then build it with your
-chosen build tool and then run the built Tutorial executable.
-
-Which function gives better results, Step1’s sqrt or Step2’s mysqrt?
diff --git a/Help/guide/tutorial/Step2/tutorial.cxx b/Help/guide/tutorial/Step2/tutorial.cxx
index 5ba34e8..f2ab446 100644
--- a/Help/guide/tutorial/Step2/tutorial.cxx
+++ b/Help/guide/tutorial/Step2/tutorial.cxx
@@ -8,6 +8,7 @@
 int main(int argc, char* argv[])
 {
   if (argc < 2) {
+    // report version
     std::cout << argv[0] << " Version " << Tutorial_VERSION_MAJOR << "."
               << Tutorial_VERSION_MINOR << std::endl;
     std::cout << "Usage: " << argv[0] << " number" << std::endl;