Re: [PATCH 1/2] doc: add an option to have Asciidoctor build man pages directly

> From: Felipe Contreras <felipe.contreras@gmail.com>
> 
> Asciidoctor contains a converter to generate man pages.  In some
> environments, where building only the manual pages and not the other
> documentation is desired, installing a toolchain for building
> DocBook-based manual pages may be burdensome, and using Asciidoctor
> directly may be easier, so let's add an option to build manual pages
> using Asciidoctor without the DocBook toolchain.

> We generally require Asciidoctor 1.5, but versions before 1.5.3 didn't
> contain proper handling of the apostrophe, which is controlled normally
> by the GNU_ROFF option.  This option for the DocBook toolchain, as well
> as newer versions of Asciidoctor, makes groff output an ASCII apostrophe
> instead of a Unicode apostrophe in text, so as to make copy and pasting
> commands easier.  These newer versions of Asciidoctor detect groff and
> do the right thing in all cases, so the GNU_ROFF option is obsolete in
> this case.

> We also need to update the code that tells Asciidoctor how to format our
> linkgit macros so that it can output proper code for man pages.  Be
> careful to reset the font to the previous after the change.  In order to
> do so, we must reset to the previous after each font change so the
> previous state at the end is the state before our inserted text, since
> troff only remembers one previous font.
> 
> Because Asciidoctor versions before 2.0 had a few problems with man page
> output, let's default this to off for now, since some common distros are
> still on 1.5.  If users are using a more modern toolchain or don't care
> about the rendering issues, they can enable the option.

> Suggested-by: Bagas Sanjaya <bagasdotme@gmail.com>
> Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
> Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
> ---
> I've preserved Felipe's authorship on this patch because much of it is
> his work.  However, I have made some substantial changes here with which
> I suspect he will disagree, in addition to expanding on the commit
> message, so if he would prefer, I can reroll with the authorship
> changed.  I have no preference myself.
> 
>   Documentation/Makefile                  | 10 ++++++++++
>   Documentation/asciidoctor-extensions.rb |  2 ++
>   Makefile                                |  3 +++
>   3 files changed, 15 insertions(+)
> 
> diff --git a/Documentation/Makefile b/Documentation/Makefile
> index 2aae4c9cbb..536d9a5f3d 100644
> --- a/Documentation/Makefile
> +++ b/Documentation/Makefile
> @@ -196,6 +196,9 @@ ASCIIDOC_EXTRA += -alitdd='&\#x2d;&\#x2d;'
>   DBLATEX_COMMON =
>   XMLTO_EXTRA += --skip-validation
>   XMLTO_EXTRA += -x manpage.xsl
> +ifdef USE_ASCIIDOCTOR_MANPAGE
> +TXT_TO_MAN = $(ASCIIDOC_COMMON) -b manpage

> +endif
>   endif
>   
>   SHELL_PATH ?= $(SHELL)
> @@ -367,9 +370,16 @@ $(OBSOLETE_HTML): %.html : %.txto asciidoc.conf asciidoctor-extensions.rb GIT-AS
>   manpage-base-url.xsl: manpage-base-url.xsl.in
>   	$(QUIET_GEN)sed "s|@@MAN_BASE_URL@@|$(MAN_BASE_URL)|" $< > $@
>   
> +ifdef TXT_TO_MAN
> +%.1 %.5 %.7 : %.txt asciidoc.conf asciidoctor-extensions.rb GIT-ASCIIDOCFLAGS
> +	$(QUIET_ASCIIDOC)$(RM) $@+ $@ && \
> +	$(TXT_TO_MAN) -o $@+ $< && \
> +	mv $@+ $@
> +else
>   %.1 %.5 %.7 : %.xml manpage-base-url.xsl $(wildcard manpage*.xsl)
>   	$(QUIET_XMLTO)$(RM) $@ && \
>   	$(XMLTO) -m $(MANPAGE_XSL) $(XMLTO_EXTRA) man $<
> +endif
>   
>   %.xml : %.txt asciidoc.conf asciidoctor-extensions.rb GIT-ASCIIDOCFLAGS
>   	$(QUIET_ASCIIDOC)$(RM) $@+ $@ && \
> diff --git a/Documentation/asciidoctor-extensions.rb b/Documentation/asciidoctor-extensions.rb
> index d906a00803..40fa87b121 100644
> --- a/Documentation/asciidoctor-extensions.rb
> +++ b/Documentation/asciidoctor-extensions.rb
> @@ -15,6 +15,8 @@ module Git
>             "#{target}(#{attrs[1]})</ulink>"
>           elsif parent.document.basebackend? 'html'
>             %(<a href="#{prefix}#{target}.html">#{target}(#{attrs[1]})</a>)
> +        elsif parent.document.basebackend? 'manpage'
> +          %(\\fB#{target}\\fP\\fR(#{attrs[1]})\\fP)
>           elsif parent.document.basebackend? 'docbook'
>             "<citerefentry>\n" \
>               "<refentrytitle>#{target}</refentrytitle>" \
> diff --git a/Makefile b/Makefile
> index 93664d6714..cb75dec314 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -285,6 +285,9 @@ all::
>   # Define USE_ASCIIDOCTOR to use Asciidoctor instead of AsciiDoc to build the
>   # documentation.
>   #
> +# Define USE_ASCIIDOCTOR_MANPAGE to use Asciidoctor's manual page backend
> +# instead of building manual pages from DocBook.
> +#