Allow Javadoc-style comment blocks with a Doxyfile variable

Javadoc allows comments like this (which I refer to as "banner" comments)

/*****************
 *
 *****************/

but doxygen does not recognize them.

Instead, the doxygen manual says to do this

/*************//**
 *
 ****************/

which some users aren't even aware is required. It also behaves poorly with clang-format.

I'm proposing to add a Doxyfile boolean option JAVADOC_BANNER which will default to NO. When set to YES, it will consider the first and second comments above to be equivalent.

However, I don't believe that the JAVADOC_BANNER option should default to YES, as there are likely a number of projects who have used the former syntax with full expectation that it would *not* appear in their documentation.

At least having the JAVADOC_BANNER default to NO allows users to opt-in voluntarily by adding JAVADOC_BANNER = YES to their Doxyfile. If the consensus is to make it a default at a later time, first a warning can be added during build that should trigger users to modify their comment style, and then eventually the default could be set to JAVADOC_BANNER = YES, or the config option could be removed entirely and it would just always be enabled.

3 files changed, 68 insertions, 0 deletions

diff --git a/examples/CMakeLists.txt b/examples/CMakeLists.txt
index 0f34c6d..967f3d4 100644
--- a/examples/CMakeLists.txt
+++ b/examples/CMakeLists.txt
@@ -23,6 +23,7 @@ add_custom_target(examples
                 ${PROJECT_BINARY_DIR}/html/examples/enum/html/index.html
                 ${PROJECT_BINARY_DIR}/html/examples/file/html/index.html
                 ${PROJECT_BINARY_DIR}/html/examples/func/html/index.html
+                ${PROJECT_BINARY_DIR}/html/examples/javadoc-banner/html/index.html
                 ${PROJECT_BINARY_DIR}/html/examples/page/html/index.html
                 ${PROJECT_BINARY_DIR}/html/examples/relates/html/index.html
                 ${PROJECT_BINARY_DIR}/html/examples/author/html/index.html
@@ -85,6 +86,13 @@ add_custom_command(
 )
 
 add_custom_command(
+	COMMAND ${EXECUTABLE_OUTPUT_PATH}/doxygen javadoc-banner.cfg
+        COMMAND ${PYTHON_EXECUTABLE}  ${TOP}/examples/strip_example.py  < ${PROJECT_BINARY_DIR}/html/examples/javadoc-banner/latex/refman.tex > ${PROJECT_BINARY_DIR}/html/examples/javadoc-banner/latex/refman_doc.tex
+	DEPENDS doxygen javadoc-banner.h javadoc-banner.cfg ${TOP}/examples/strip_example.py
+	OUTPUT ${PROJECT_BINARY_DIR}/html/examples/javadoc-banner/html/index.html ${PROJECT_BINARY_DIR}/html/examples/javadoc-banner/latex/refman_doc.tex
+)
+
+add_custom_command(
 	COMMAND ${EXECUTABLE_OUTPUT_PATH}/doxygen page.cfg
         COMMAND ${PYTHON_EXECUTABLE}  ${TOP}/examples/strip_example.py  < ${PROJECT_BINARY_DIR}/html/examples/page/latex/refman.tex > ${PROJECT_BINARY_DIR}/html/examples/page/latex/refman_doc.tex
 	DEPENDS doxygen page.doc page.cfg ${TOP}/examples/strip_example.py
diff --git a/examples/javadoc-banner.cfg b/examples/javadoc-banner.cfg
new file mode 100644
index 0000000..d650dbc
--- /dev/null
+++ b/examples/javadoc-banner.cfg
@@ -0,0 +1,15 @@
+PROJECT_NAME     = "Javadoc Banner"
+OUTPUT_DIRECTORY = ../html/examples/javadoc-banner
+GENERATE_LATEX   = YES
+GENERATE_MAN     = NO
+GENERATE_RTF     = NO
+CASE_SENSE_NAMES = NO
+INPUT            = javadoc-banner.h
+STRIP_CODE_COMMENTS = NO
+QUIET            = YES
+JAVADOC_AUTOBRIEF = YES
+JAVADOC_BANNER = YES
+SEARCHENGINE     = NO
+COMPACT_LATEX = YES
+LATEX_HIDE_INDICES     = YES
+EXTRACT_ALL = YES
diff --git a/examples/javadoc-banner.h b/examples/javadoc-banner.h
new file mode 100644
index 0000000..bc413bb
--- /dev/null
+++ b/examples/javadoc-banner.h
@@ -0,0 +1,45 @@
+/**
+ * A brief history of JavaDoc-style (C-style) comments.
+ *
+ * This is the typical JavaDoc-style C-style comment. It starts with two
+ * asterisks.
+ *
+ * @param theory Even if there is only one possible unified theory. it is just a
+ *               set of rules and equations.
+ */
+void cstyle( int theory );
+
+/*******************************************************************************
+ * A brief history of JavaDoc-style (C-style) banner comments.
+ *
+ * This is the typical JavaDoc-style C-style "banner" comment. It starts with
+ * a forward slash followed by some number, n, of asterisks, where n > 2. It's
+ * written this way to be more "visible" to developers who are reading the
+ * source code.
+ *
+ * Often, developers are unaware that this is not (by default) a valid Doxygen
+ * comment block!
+ *
+ * However, as long as JAVADOC_BLOCK = YES is added to the Doxyfile, it will
+ * work as expected.
+ *
+ * This style of commenting behaves well with clang-format.
+ *
+ * @param theory Even if there is only one possible unified theory. it is just a
+ *               set of rules and equations.
+ ******************************************************************************/
+void javadocBanner( int theory );
+
+/***************************************************************************//**
+ * A brief history of Doxygen-style banner comments.
+ *
+ * This is a Doxygen-style C-style "banner" comment. It starts with a "normal"
+ * comment and is then converted to a "special" comment block near the end of
+ * the first line. It is written this way to be more "visible" to developers
+ * who are reading the source code.
+ * This style of commenting behaves poorly with clang-format.
+ *
+ * @param theory Even if there is only one possible unified theory. it is just a
+ *               set of rules and equations.
+ ******************************************************************************/
+void doxygenBanner( int theory );