fish-shell/cmake/Docs.cmake
Johannes Altmanninger c0d1e41313 docs synopsis: add HTML highlighing and automate manpage markup
Recent synopsis changes move from literal code blocks to
[RST line blocks].  This does not translate well to HTML: it's not
rendered in monospace, so aligment is lost.  Additionally, we don't
get syntax highlighting in HTML, which adds differences to our code
samples which are highlighted.

We hard-wrap synopsis lines (like code blocks). To align continuation
lines in manpages we need [backslashes in weird places]. Combined with
the **, *, and `` markup, it's a bit hard to get the alignment right.

Fix these by moving synopsis sources back to code blocks and compute
HTML syntax highlighting and manpage markup with a custom Sphinx
extension.

The new Pygments lexer can tokenize a synopsis and assign the various
highlighting roles, which closely matches fish's syntax highlighing:
- command/keyword (dark blue)
- parameter (light blue)
- operator like and/or/not/&&/|| (cyan)
- grammar metacharacter (black)

For manpage output, we don't project the fish syntax highlighting
but follow the markup convention in GNU's man(1):

	bold text          type exactly as shown.
	italic text        replace with appropriate argument.

To make it easy to separate these two automatically, formalize that
(italic) placeholders must be uppercase; while all lowercase text is
interpreted literally (so rendered bold).
This makes manpages more consistent, see string-join(1) and and(1).

Implementation notes:
Since we want manpage formatting but Sphinx's Pygments highlighing
plugin does not support manpage output, add our custom "synopsis"
directive.  This directive parses differently when manpage output is
specified. This means that the HTML and manpage build processes must
not share a cache, because the parsed doctrees are cached.  Work around
this by using separate cache locations for build targets "sphinx-docs"
(which creates HTML) and "sphinx-manpages".  A better solution would
be to only override Sphinx's ManualPageBuilder but that would take a
bit more code (ideally we could override ManualPageWriter but Sphinx
4.3.2 doesn't really support that).

---

Alternative solution: stick with line blocks but use roles like
:command: or :option: (or custom ones). While this would make it
possible to produce HTML that is consistent with code blocks (by adding
a bit of CSS), the source would look uglier and is harder to maintain.
(Let's say we want to add custom formatting to the [|] metacharacters
in HTML.  This is much easier with the proposed patch.)

---

[RST line blocks]: https://docutils.sourceforge.io/docs/ref/rst/restructuredtext.html#line-blocks
[backslashes in weird places]: https://github.com/fish-shell/fish-shell/pull/8626#discussion_r782837750
2022-01-19 22:56:41 +08:00

86 lines
2.9 KiB
CMake

find_program(SPHINX_EXECUTABLE NAMES sphinx-build
HINTS
$ENV{SPHINX_DIR}
PATH_SUFFIXES bin
DOC "Sphinx documentation generator")
include(FeatureSummary)
set(SPHINX_SRC_DIR "${CMAKE_CURRENT_SOURCE_DIR}/doc_src")
set(SPHINX_ROOT_DIR "${CMAKE_CURRENT_BINARY_DIR}/user_doc")
set(SPHINX_BUILD_DIR "${SPHINX_ROOT_DIR}/build")
set(SPHINX_HTML_DIR "${SPHINX_ROOT_DIR}/html")
set(SPHINX_MANPAGE_DIR "${SPHINX_ROOT_DIR}/man")
# sphinx-docs uses fish_indent for highlighting.
# Prepend the output dir of fish_indent to PATH.
add_custom_target(sphinx-docs
mkdir -p ${SPHINX_HTML_DIR}/_static/
COMMAND env PATH="$<TARGET_FILE_DIR:fish_indent>:$$PATH"
${SPHINX_EXECUTABLE}
-j auto
-q -b html
-c "${SPHINX_SRC_DIR}"
-d "${SPHINX_ROOT_DIR}/.doctrees-html"
"${SPHINX_SRC_DIR}"
"${SPHINX_HTML_DIR}"
DEPENDS ${SPHINX_SRC_DIR}/fish_indent_lexer.py fish_indent
COMMENT "Building HTML documentation with Sphinx")
# sphinx-manpages needs the fish_indent binary for the version number
add_custom_target(sphinx-manpages
env PATH="$<TARGET_FILE_DIR:fish_indent>:$$PATH"
${SPHINX_EXECUTABLE}
-j auto
-q -b man
-c "${SPHINX_SRC_DIR}"
-d "${SPHINX_ROOT_DIR}/.doctrees-man"
"${SPHINX_SRC_DIR}"
# TODO: This only works if we only have section 1 manpages.
"${SPHINX_MANPAGE_DIR}/man1"
DEPENDS fish_indent
COMMENT "Building man pages with Sphinx")
if(SPHINX_EXECUTABLE)
option(BUILD_DOCS "build documentation (requires Sphinx)" ON)
else(SPHINX_EXECUTABLE)
option(BUILD_DOCS "build documentation (requires Sphinx)" OFF)
endif(SPHINX_EXECUTABLE)
if(BUILD_DOCS AND NOT SPHINX_EXECUTABLE)
message(FATAL_ERROR "build documentation selected, but sphinx-build could not be found")
endif()
if(IS_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/user_doc/html
AND IS_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/user_doc/man)
set(HAVE_PREBUILT_DOCS TRUE)
else()
set(HAVE_PREBUILT_DOCS FALSE)
endif()
if(BUILD_DOCS OR HAVE_PREBUILT_DOCS)
set(INSTALL_DOCS ON)
else()
set(INSTALL_DOCS OFF)
endif()
add_feature_info(Documentation INSTALL_DOCS "user manual and documentation")
if(BUILD_DOCS)
configure_file("${SPHINX_SRC_DIR}/conf.py" "${SPHINX_BUILD_DIR}/conf.py" @ONLY)
add_custom_target(doc ALL
DEPENDS sphinx-docs sphinx-manpages)
# Group docs targets into a DocsTargets folder
set_property(TARGET doc sphinx-docs sphinx-manpages
PROPERTY FOLDER cmake/DocTargets)
elseif(HAVE_PREBUILT_DOCS)
if(NOT CMAKE_CURRENT_SOURCE_DIR STREQUAL CMAKE_CURRENT_BINARY_DIR)
# Out of tree build - link the prebuilt documentation to the build tree
add_custom_target(link_doc ALL)
add_custom_command(TARGET link_doc
COMMAND ${CMAKE_COMMAND} -E create_symlink ${CMAKE_CURRENT_SOURCE_DIR}/user_doc ${CMAKE_CURRENT_BINARY_DIR}/user_doc
POST_BUILD)
endif()
endif(BUILD_DOCS)