[Buildroot] [PATCH 23/23 v5] docs/manual: document the asciidoc infra

[Yann E. MORIN]

Signed-off-by: "Yann E. MORIN" <yann.morin.1998 at free.fr>
Cc: Samuel Martin <s.martin49 at gmail.com>
Cc: Thomas De Schampheleire <patrickdepinguin at gmail.com>
---
 docs/manual/adding-packages-asciidoc.txt | 118 +++++++++++++++++++++++++++++++
 docs/manual/adding-packages.txt          |   2 +
 2 files changed, 120 insertions(+)
 create mode 100644 docs/manual/adding-packages-asciidoc.txt

diff --git a/docs/manual/adding-packages-asciidoc.txt b/docs/manual/adding-packages-asciidoc.txt
new file mode 100644
index 0000000..b8821ee
--- /dev/null
+++ b/docs/manual/adding-packages-asciidoc.txt
@@ -0,0 +1,118 @@
+// -*- mode:doc; -*-
+// vim: syntax=asciidoc
+
+=== Infrastructure for asciidoc documents
+
+[[asciidoc-documents-tutorial]]
+
+The Buildroot manual, which you are currently reading, is entirely written
+using the http://asciidoc.org/[AsciiDoc] mark-up syntax. The manual is then
+rendered to many formats:
+
+* +HTML+
+* +SPLIT_HTML+
+* +PDF+
+* +EPUB+
+* +TEXT+
+
+Although Buildroot only contains one document written in AsciiDoc, there
+is, as for packages, an infrastructure for rendering documents using the
+AsciiDoc syntax.
+
+Also as for packages, the AsciiDoc infrastructure is available from
+xref:outside-br-custom[BR2_EXTERNAL]. This allows documentation for a
+BR2_EXTERNAL tree to match the Buildroot documentation, as it will be
+rendered to the same formats and use the same layout and theme.
+
+==== +asciidoc-document+ tutorial
+
+Whereas packages infrastructures are suffixed with +-package+, the documents
+infrastructures are suffixed with +-document+. So, the AsciiDoc infrastructure
+is named +asciidoc-document+.
+
+Here is an example to render a simple AsciiDoc document.
+
+----
+01: ################################################################################
+02: #
+03: # foo-document
+04: #
+05: ################################################################################
+06: 
+07: FOO_SOURCES = $(sort $(widcard $(pkgdir)/*))
+08: $(eval $(call asciidoc-document))
+----
+
+On line 7, the Makefile declares what the sources of the document are.
+Currently, it is expected that the document's sources are only local;
+Buildroot will not attempt to download anything to render a document.
+Thus, you must indicate where the sources are. Usually, the string
+above is sufficient for a document with no sub-directory structure.
+
+Finally, on line 8, we call the +asciidoc-document+ function, which 
+generates all the Makefile code necessary to render the document.
+
+==== +asciidoc-document+ reference
+
+The list of variables that can be set in a +.mk+ file to give metadata
+information is (assuming the document name is +foo+) :
+
+* +FOO_SOURCES+, mandatory, defines the source files for the document.
+
+* +FOO_RESSOURCES+, optional, may contain a space-separated list of paths
+  to so-called ressources (CSS, images...) By default, none.
+
+There are also additional hooks (see xref:hooks[] for what a hook is),
+that a document may set to define extra actions to be done at various
+steps:
+
+* +FOO_POST_EXTRACT_HOOKS+ to run additional commands after the sources
+  have been copied by Buildroot. This can be used for, for example,
+  generating part of the manual with information extracted from the
+  tree. As an example, Buildroot uses that to generate the tables in the
+  appendices.
+
+* +FOO_EXTRA_CHECK_DEPENDENCIES_HOOKS+ to run additional tests on required
+  components to generate the document. In AsciiDoc, it is possible to
+  call filters, that is, programs that will parse an AsciiDoc block and
+  render it appropriately (e.g. http://ditaa.sourceforge.net/[ditaa] or
+  https://pythonhosted.org/aafigure/[aafigure].)
+
+* +FOO_EXTRA_CHECK_DEPENDENCIES_<FMT>_HOOKS+, to run additional tests for
+  the specified format +<FMT>+ (see the list of rendered formats, above.)
+
+Here is a complete example that uses all variables and all hooks:
+
+----
+01: ################################################################################
+02: #
+03: # foo-document
+04: #
+05: ################################################################################
+06: 
+07: FOO_SOURCES = $(sort $(widcard $(pkgdir)/*))
+08: FOO_RESSOURCES = $(sort $(wildcard $(pkgdir)/ressources))
+09: 
+10: define FOO_GEN_EXTRA_DOC
+11:     /path/to/generate-script --outdir=$(@D)
+12: endef
+13: FOO_POST_EXTRACT_HOOK += FOO_GEN_EXTRA_DOC
+14: 
+15: define FOO_CHECK_MY_PROG
+16:     if ! which my-prog >/dev/null 2>&1; then \
+17:         echo "You need my-prog to generate the foo document"; \
+18:         exit 1; \
+19:     fi
+20: endef
+21: FOO_EXTRA_CHECK_DEPENDENCIES += FOO_CHECK_MY_PROG
+22: 
+23: define FOO_CHECK_MY_OTHER_PROG
+24:     if ! which my-other-prog >/dev/null 2>&1; then \
+25:         echo "You need my-other-prog to generate the foo document as PDF"; \
+26:         exit 1; \
+27:     fi
+28: endef
+29: FOO_EXTRA_CHECK_DEPENDENCIES_TEXT += FOO_CHECK_MY_OTHER_PROG
+30: 
+31: $(eval $(call asciidoc-document))
+----
diff --git a/docs/manual/adding-packages.txt b/docs/manual/adding-packages.txt
index 9c97128..feb0d13 100644
--- a/docs/manual/adding-packages.txt
+++ b/docs/manual/adding-packages.txt
@@ -27,6 +27,8 @@ include::adding-packages-virtual.txt[]
 
 include::adding-packages-kconfig.txt[]
 
+include::adding-packages-asciidoc.txt[]
+
 include::adding-packages-hooks.txt[]
 
 include::adding-packages-gettext.txt[]
-- 
1.9.1